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Boston Medical Library
in the Francis A. Countway
Library of Medicine -Boston
ANATOMY
DESCRIPTIVE AND SUEGICAL.
Digitized by the Internet Archive
in 2011 with funding from
Open Knowledge Commons and Harvard Medical School
http://www.archive.org/details/anatomydescripti1858gray
ANATOMY
DESCRIPTIVE AND SURGICAL.
BY
HENEY GRAY, F.R.S.
LECTURER ON ANATOMY AT SAINT GEORGE'S HOSPITAL.
THE DRAWINGS
By H. V. CARTER, M.D.
LATE DEMONSTRATOR OF ANATOMY AT ST. GEORGE'S HOSPITAL.
THE DISSECTIONS
JOINTLY BY THE AUTHOR AND DR. CARTER,
LONDON:
JOHN W. PARKER AND SON, WEST STRAND.
1858.
LONDON
PKINTKD BV WEHTHKIMER AtiTt CO.
FINSBUHV CIKCUS.
TO
SIR BENJAMIN COLLINS BRODIE, BART.,
F.R.S., D.C.L.,
SERJEANT-SURGEON TO THE QUEEN,
CORRESPONDING MEMBER OF THE INSTITUTE OF FRANCE,
THIS WORK IS DEDICATED,
IN ADMIRATION OF HIS GREAT TALENTS,
AND
IN REMEMBRANCE OF MANY ACTS OF KINDNESS
SHOWN TO THE AUTHOR,
FROM AN EARLY PERIOD OF HIS PROFESSIONAL CAREER.
PREFACE.
rPHIS Work is intended to farnisli the Student and Practitioner with an
accurate view of the Anatomy of the Human Body, and more espe-
cially the application of this science to Practical Surgery.
One of the chief objects of the Author has been, to induce the Student to
apply his anatomical knowledge to the more practical points in Surgery, by
introducing, in small type, under each subdivision of the work, such observa-
tions as shew the necessity of an accurate knowledge of the part under
examination.
Osteology. Much time and care have been devoted to this part of the work,
the basis of anatomical knowledge. It contains a concise description of the
anatomy of the bones, illustrated by numerous accurately -lettered engravings,
shewing the various markings and processes on each bone. The attachments
of each muscle are shewn in dotted lines (after the plan recently adopted by
Mr. Holden), copied from recent dissections. The articulations of each bone
are shewn on a new plan ; and a method has been adopted, by which the
hitherto complicated account of the development of the bones is made more
simple.
The Articulations. In this section, the various structures forming the joints
are described ; a classification of the joints is given ; and the anatomy of each
-carefully described : abundantly illustrated by engravings, all of which are
taken from, or corrected by, recent dissections.
The Muscles and Fascice. In this section, the muscles are described in
groups, as in ordinary anatomical works. A series of illustrations, shewing the
hues of incision necessary in the dissection of the muscles in each region, are
introduced, and the muscles are shewn in fifty-two engravings. The Surgical
Anatomy of the muscles in connection with fractures, of the tendons or
muscles divided in operations, is also described and illustrated.
The Arteries. The course, relations, and Surgical Anatomy of each artery
are described in this section, together with the anatomy of the regions con-
taining the arteries more especially involved in surgical operations. This part
of the work is illustrated by twenty-seven engravings.
The Veins are described as in ordinary anatomical works ; and illustrated
by a series of eng-ravings, shewing those in each region. The veins of the spine
are described and illustrated from the well-known work of Breschet.
viii PREFACE.
The Lymphatics are described, and figured in a series of illustrations copied
from tlie elaborate work of Mascagni,
The Nervous System and Organs of Sense. A concise and accurate descrip-
tion of this important part of anatomy has been given, illustrated by seventy-
two engravings, shewing the spinal cord and its membranes; the anatomy of the
brain, in a series of sectional views; the origin, course, and distribution of the
cranial, spinal, and sympathetic nerves; and the anatomy of the organs of
sense.
The Viscera. A detailed description of this essential part of anatomy has
been given, illustrated by fifty large, accurately-lettered engravings.
Regional Anatomy. The anatomy of the perinseum, of the ischio-rectal
region, and of femoral and inguinal hernise, is described at the end of the
work; the region of the neck, the axilla, the bend of the elbow, Scarpa's
triangle, and the popliteal space, in the section on the arteries; the laryngo-
tracheal region, with the anatomy of the trachea and larynx. The regions
are illustrated by many engravings.
Microscopical Anatomy. A brief account of the microscopical anatomy of
some of the tissues, and of the various organs, has also been introduced.
The Author gratefully acknowledges the great services he has derived, in
the execution of this work, from the assistance of his friend, Dr. H.V. Carter,
late Demonstrator of Anatomy at St. George's Hospital. All the drawings
from which the engravings were made, were executed by him. In the majo-
rity of cases, they have been copied from, or corrected by, recent dissections,
made jointly by the Author and Dr. Carter.
The Author has also to thank his friend, Mr. T. Holmes, for the able
assistance afforded him in correcting the proof-sheets in their passage through
the press.
The engravings have been executed by Messrs. Butterworth and Heath ;
and the Author cannot omit thanking these gentlemen for the great care and
fidelity displayed in their execution.
Wilton-Street, Belgrave-Square,
August, 1858.
CONTENTS.
Osteology.
General Properties of Bone .
Chemical Composition of Bone
Structure of Bone
Form of Bones
Vessels of Bone
Development of Bone .
Growth of Bone .
The Skeleton
The Spine.
General Characters of the Vertebrae . 5
Characters of the Cervical Vertebrae . 5
Atlas
. 6
Axis
. 7
Vertebra Prominens
. S
Characters of the Dorsal Vertebrae
. .8
Peculiar Dorsal Vertebrae
. 9
Characters of the Lumbar Vertebrae . 10
Structure of the Vertebrae .
. 10
Development of the Vertebrae
. 11
Atlas ,
. 12
Axis
. 12
7th Cervical
. 12
Lumbar Vertebrae 12
Progress of Ossification in the Spine . 12
False Vertebrae
. 12
The Sacrum ....
. 12
The Coccyx ....
. 16
Development of the Coccyx
. 17
Of the Spine in general
. 17
The Skull.
Bones of the Cranium .
. 19
Occipital Bone
. 19
Parietal Bones
, 22
Frontal Bone .
, 24
Temporal Bones
. 27
Sphenoid Bone
. 32
Sphenoidal Spongy Bones
. 36
Ethmoid Bone
. 37
Wormian Bones
. 39
Bones of the Face
. 39
Nasal Bones .
. 39
Superior Maxillary Bones
. 40
Lachrymal Bones .
. 44
Malar Bones .
. 45
Palate Bones .
. 46
Inferior Turbinated Bones
. 49
Vomer ....
. 50
Lower Jaw
. 50
Articulations of the Cranial Bone
s . 53
Sutures of the Skull .
. 54
Vertex of the Skull
Base of the Skull, Internal Surface
Anterior Fossa .
Middle Fossa
Posterior Fossa .
Base of Skull, External Surface
Lateral Regions of the Skull
Temporal Fossae .
Zygomatic Fossae .
Spheno-masillary Fossae
Anterior Eegion of Skull
Orbits ....
Nasal Fossae . . ^ .
Os Hyoides .
The Tliorax.
The Sternum
Development of the Sternum
The Ribs ....
Peculiar Ribs
Costal Cartilages .
The Pelvis.
Os Innominatum ....
Ilium
Ischium
Pubes
Development of the Os Innominatum
Boundaries of Pelvis
Position of Pelvis ....
Axes of Pelvis ....
Differences between the Male and Fe-
male Pelvis
The Upper Extremities.
The Clavicle . . . •
The Scapula
Development of the Scapula
The Humerus
Development of the Humerus
The Ulna ' •
The Radius
The Hand
The Carpus
Bones of Upper Row
Bones of Lower Row
The Metacarpus
Peculiar Metacarpal Bones .
Phalanges
Development of the Hand .
The Lower Extremities.
The Femur
Development of the Femur .
b
PAGE.
. 55
. 55
. 55
. 57
. 57
. 58
. 61
. 61
. 62
. 62
. 62
. 64
. 65
. 67
68
70
71
73
75
76
76
79
80
81
82
83
84
84
84
86
90
91
95
97
100
102
102
103
105
107
108
109
110
111
il5
X
CONTENTS.
PAGE
PACE
The Leg ....
. 115
Astragalus ....
. 125
Patella ....
. 116
Scaphoid ....
. 127
Tibia . ...
. 116
Internal Cuneiform
. 127
Development of Tibia .
. 120
Middle Cuneiform
. 128
Fibula
. 120
External Cuneiform
. 128
Development of Fibula
. 122
Metatarsal Bones
, 129
Tbe Foot ....
. 122
Peculiar Metatarsal Bones .
. 129
Tarsus ....
. 122
Phalanges ....
. 130
Os Calcis ....
. 122
Development of the Foot
. 130
Cuboid ....
. 124
Sesamoid Bones .
. 131
Tlie Articulations.
General Anatomy of the Joints
Cartilage
. 133
. 133
Fibro-cartilage
. 133
Ligament
. 134
Synovial Membrane
Forms of Articulation .
. 134
. 135
Synarthrosis .
Amphiarthrosis
Diarthrosis
. 135
. 136
. 136
Movements of Joints
. 138
Gliding Movement
Angular Movement
Circumduction
. 138
. 138
. 138
Eotation
. 138
Articulations of the Trunk.
Articulations of the Vertebral Column , 138
Atlas with the Axis 141
Atlas with the Oc-
cipital Bone . 143
Axis with the Oc-
cipital Bone . 144
Temporo-maxillary Articulation . . 145
Articulation of the Ribs with the Ver-
tebrae 147
Costo-vertebral . . . .147
Costo-transverse . . . .148
Costo-sternal Articulations . . .150
Costo-xiphoid Ligaments . . .151
Intercostal Articulations . . . 151
Ligaments of the Sternum . . .151
Articulation of the Pelvis with the
Spine . . 152
Sacrum and Ilium . 153
Sacrum and Ischium 154
Sacrum and Coccyx . 155
Inter-pubic 155
Articulations of the 'U202wr Extremity.
Sterno-clavicular 156
Scapulo-clavicular . . . .158
Ligaments of the Scapula . . . 159
Shoulder-joint 160
Elbow-joint 161
Radio-ulnar Articulation . . . 163
Wrist-joint 164
Articulations of the Cai'pus . .166
Carpo-metacarpal Articulations . .168
Metacarpo-phalangeal Articulations . 1 69
Articulation of the Phalanges . .170
Articulations of the Lower Extremity.
Hip-joint 170
Knee-joint ...... 172
Articulations between the Tibia and
Fibula 176
Ankle-joint 178
Articulations of the Tarsus . . . 180
Tarso-metatarsal Articulations . .183
Articulations of the Metatarsus . . 183
Metatarso-phalangeal Articulations . 184
Articulations of the Phalanges . .184
Muscles and Fasciae.
185
186
187
General Anatomy of Muscles
of Fasciae
Muscles and Fascia of the Head
AND Face.
Subdivision into Groups
Epicranial Region.
Dissection 188
Fascia of Head, Occipito-frontalis . IBS
Auricular Region.
Dissection 190
AttoUens Aurem, Attrahens Aurem . 190
Eetrahens Aurem, Actions . . . 191
Palpebral Region.
Dissection 191
Orbicularis Palpebrarum . . . 191
Corrugator Supercilii . . . .191
Tensor Tarsi, Actions . . . .192
Oriital Region.
Dissection 192
Levator Paljjebrse . . . .192
Rectus Superior, Inferior and External
Recti 193
Superior Oblique 1 93
Inferior Obhque 194
Actions, Surgical Anatomy of . . 195
Nasal Region.
Pyramidalis Nasi 195
Levator Labii Superioris Alaeque
Nasi 195
Dilator Naris, Anterior and Posterior . 195
Compressor Nasi 195
Narium Minor . . . 195
Depressor Alae Nasi , . . .195
Actions 195
CONTENTS.
Stqjerior Maxillary Regio7i.
Levator Labii Superioris Propvius . 196
Levator Anguli Oris . . . .196
Zygomatici, Actions . . . .196
Iiiferior Maxillary Region.
Dissection 196
Levator Labii Inferioris . . .196
Depressor Labii Inferioris . . . 197
Depressor Anguli Oris .... 197
Intermaxillary Region.
Dissection 197
Orbiculai'is Oris 197
Buccinator 198
Eisorius 198
Actions 198
Tempero-Maxillary Region.
Masseter 198
Temporal Fascia ..... 199
Dissection of Temporal Muscle . . 199
Temporal 200
Ptery go-Maxillary Region.
Dissection 200
Internal Pterygoid .... 200
External Pterygoid .... 201
Actions 201
Muscles and Fasciae of the JSTeck.
Subdivision into Groups . . . 201
Superficial Region.
Dissection 202
Superficial Cervical Fascia . . . 202
Platysma Myoides .... 202
Deep Cervical Fascia .... 203
Sterno-cleido-mastoid .... 204
Boundaries of the Triangles of the Neck 204
Actions 205
Infra-Hyoid Region.
Dissection ....
Sterno-hyoid
Sterno-thyroid, Thyro-hyoid
Omo-hyoid, Actions
Snpra-Iiyoid Region.
Dissection ....
Digastric ....
Stylo-hyoid, Mylo-hyoid
Genio-hyoid
Actions ....
. 205
. 205
. 206
. 207
. 207
. 207
. 208
. 208
. 209
. 209
. 209
. 210
. 210
. 211
Lingual Region.
Dissection ....
Genio-hyo-glossus
Hyo-glossus, Lingualis
Stylo-glossus, Palato-glossus
Actions ....
Pharyngeal Region.
Dissection 211
Inferior Constrictor . . . .211
Middle Constrictor, Superior Constrictor 212
Stylo-pharyngeus, Actions . . .212
Palatal Region.
Dissection 213
Levator Palati . . . . .213
Tensor Palati, Azygos Uvulae . . 214
Palato-glossus, Palato-pharyngeus . 214
Actions. Surgical Anatomy . . 215
Vertebral Region, (Anterior).
Eectus Capitis Anticus Major . . 215
Rectus Capitis Anticus Minor . .215
Eectus Lateralis 215
Longus Colli 216
Vertebral Region, {Lateral).
Scalenus Anticus, Scalenus Medius . 217
Scalenus Posticus, Actions . . .217
Muscles and Fascia of the Trunk.
Subdivision into Groups . . "217
Muscles of the Bach.
Subdivision into Layers . . 217, 218
First Layer.
Dissection 218
Trapezius 218
Ligamentum Nuchte . . . .220
Latissimus Dorsi .... 220
Second Layer.
Dissection 221.
Levator Anguli Scapulas . . . 221
Rhomboideus Minor and Major . . 221
Actions 222
Third Layer.
Dissection 222
Serratus Posticus Superior and Inferior. 222
Vertebral Aponeurosis . . . 222
Splenius Capitis and Colli . . . 223
Actions 223
Fourth Layer.
Dissection 223
Erector Spin« 223
Sacro-lumbalis 225
MusculusAccessorius adSacro-lumbalem 225
Cervicalis Ascendens .... 225
Longissimus Dorsi .... 225
Transversalis Colli .... 225
Trachelo-mastoid .... 225
Spinalis Dorsi, Spinalis Cervicis . . 226
Complexus . ..... 226
Biventer Cervicis .... 226
Fifth Layer.
Dissection 227
Semispiualis Dorsi and Colli . . 227
Multifidus Spinse .... 227
Rotatores Spinee .... 227
Supraspinales 227
Interspinales 228
Extensor Coccygis, Intertransversajes . 228
Rectus Posticus Major and Minor . 228
Obliquus Superior and Inferior . . 228
Actions 229
Muscles of the Abdomen.
Dissection ...... 229
Obliquus Externus .... 230
Obhquus Internus .... 231
Transversalis 233
Lumbar Fascia 233
Rectus 234
Pyramidalis, Quadratus Lumborum , 235
Linea Alba, Line* Semilunares . . 236
Linese Transversa3 .... 236
Actions . .... 236
b 2
CONTENTS.
Muscles and Fasciae of the Thokax.
Intercostal Fasciae .... 237
Intercostales Interni et Externi
Infracostales, Triangularis Sterni
Levatores Costarum
Actions ....
Diaphragmatic Region.
Diaphragm ....
Actions ....
237
237
238
238
238
240
Muscles and Fascia of the Upper
Extremity.
Subdivision into Groups , . . 241
Dissection of Pectoral Region and Axilla 242
Fasciifi of the Thorax , . .242
Anterior Thoracic Region.
Pectoralis Major 242
Costo-coracoid Membrane . . . 244
Pectoralis Minor 244
Subclavius, xlctions .... 245
Lateral Thoracic Region.
Sei-ratus Magnus, Actions . . . 247
Acromial Region.
Deltoid, Action 247
Anterior Scaimlar Region.
Subscapular Aponeurosis . . . 247
Subscapularis, Actions . . . 248
Posterior Scajmlar Region.
Supra-spinous Aponeurosis . , 248
Supra-spinatus 248
Infra- spinous Aponeurosis . . . 248
Infra-spinatus 249
Teres Minor 249
Teres Major, Actions .... 250
Anterior Humeral Region.
Deep Fascia of Arm . . . . 250
Coraco-brachialis, Biceps . . .251
Brachialis Anticus, Actions . . 252
Posterior Humeral Region.
Triceps 252
Sub-anconeus, Actions . . . 253
Miiscles of Fore-arm.
Deep Fascia of Fore-arm
Anterior Brachial Region, Supo^ficial
Layer.
Pronator Radii Teres .
Flexor Carpi Radialis .
Palmaris Longus
Flexor Carpi Ulnaris .
Flexor Digitorum Sublimis
Anterior Brachial Region, Beef
Layer.
Flexor Profundus Digitorum
Flexor Longus Polhcis
Pronator Quadratus
Actions
Radial Region.
Dissection
Supinator Longus
Extensor Carpi Radialis Longior
Extensor Carpi Radialis Brevior
253
254
254
255
255
255
256
257
257
258
258
258
258
259
Posterior Brachial Region, Superficial
Layer.
Extensor Communis Digitorum . . 260
Extensor Minimi Digiti . . . 260
Extensor Carpi Ulnaris . . .260
Anconeus 261
Posterior Brachial Region, Beej) Layer.
Supinator Brevis .... 261
Extensor Ossis Metacarpi PoUicis . 261
Extensor Primi Internodii Pollicis . 261
Extensor Secundii Internodii Pollicis . 262
Extensor Indicis 262
Actions 263
Muscles and Fascice of the Hand.
Dissection 263
Anterior Annular Ligament . . 263
Posterior Annular Ligament . . 263
Palmar Fascia 264
Muscles of the Hand.
Radial Group 264
Ulnar Group 266
Middle Palmar Group .... 267
Actions 268
Surgical Anatomy oj the Muscles of the
TJ'pfer Extremity.
Fractures of the Clavicle , . . 268
Acromian Process . 269
Coracoid Process . 269
Humerus . . 269
Ulna . . .271
Olecranon . . 271
Radius . . .271
Muscles and Fascia of the Lower
Extremity.
Subdivision into groups . . . 273
Iliac Region.
Dissection ....
. 274
Iliac Fascia ....
. 274
Psoas Magnus, Psoas Parvus
. 275
Iliacus ....
. 275
Actions ....
. 276
Anterior Femoral Region.
Dissection 276
Fascise of the Thigh, Superficial Fascia . 276
Deep Fascia (Fascia Lata) . . . 277
Saphenous Opening .... 278
Iliac and Pubic Portions of Fascia Lata 278
Tensor Vagingg Femoris, Sartorius . 278
Quadriceps Extensor Cruris . . 279
Rectus Femoris, Vastus Exteruus . 279
Vastus Internus and Cruraeus . . 280
Sub-cruraeus, Actions .... 280
Internal Femoral Region.
Dissection 281
Gracilis 281
Pectineus, Adductor Longus . , 282
Adductor Brevis, Adductor Magnus . 282
Actions 283
Gluteal Region.
Dissection 283
Gluteus Maximus . . . .283
Gluteus Medius 284
Gluteus Minimus .... 285
Pyriformis, Obturator Internus, Gemelli 286
CONTENTS.
Quadratus Femoris, Obturator Externus 287
Actions 287
Posterior Femoral Region.
Dissection 288
Biceps, Semitendinosus . . . 288
Semimembranosus, Actions . . 289
Surgical Anatomy of Hamstring Ten-
dons 289
Muscles and Fascice of Leg.
Dissection of Front of Leg . . . 289
Fascia of the Leg .... 289
Muscles of the Leg ... . 290
Anterior Tibio-Fibular Region.
Tibialis Anticus 290
Extensor Proprius PoUicis . . .291
Extensor Longus Digitorum . ,291
Peroneus Tertius, Actions . . .291
Posterior TiUo-Fihilar Region, Superficial
Layer.
Dissection 292
Gastrocnemius . . . . .292
Soleus, Tendo Achillis, Plantaris . . 293
Actions 293
Posterior Titio-Fibular Region,
Deep Layer.
Deep Fascia of Leg .... 294
Popliteus, Flexor Longus PoUicis . 294
Flexor Longus Digitorum, Tibialis Pos-
ticus 295
Actions 296
Fibular Region.
Peroneus Longus, Peroneus Brevis . 296
Actions 297
Surgical Anatomy of Tendons around
Ankle 297
Mtiscles and FascicB of Foot.
Anterior Annular Ligament . . 297
Internal Annular Ligament . .298
External Annular Ligament . .298
Plantar Fascia 298
Muscles of the Foot, Dorsal Region.
Extensor Brevis Digitorum . . 299
Plantar Region.
Subdivision into Groups
. 299
Subdivision into Layers
. 299
First Layer
. 299
Second Layer
. 301
Third Layer
. 302
Interossei ....
. 303
Surgical Anatomy of the Ifuscles of the
Lower Extremity.
Fracture of the Neck of the Femur . 304
the Femur below Trochanter
Minor . . .304
the Femur above the Con-
dyles .... 305
the Patella . . .305
the Tibia . . . .305
the Fibula, with Dislocation
of the Tibia . . 306
The Arteries.
General Anatomy.
Subdivision into Pulmonary and Sys-
temic 307
Distribution of — Where found . . 307
Mode of Division — Anastomoses . 307
Capillaries — Structure of Arteries . 308
Sheath — Vasa Vasorum . . . 308
Aorta.
Arch of Aorta 310
Dissection 310
Ascending Part of Arch . . . 310
Transverse Part of Arch . . .311
Descending Part of Arch . . . 311
Peculiarities, Surgical Anatomy . .312
Branches 313
Peculiarities of Branches . . . 313
Coronary Arteries . . , .313
Arteria Lnnominata.
Relations 314
Peculiarities, Surgical Anatomy . 314
Common Carotid Arteries.
Course and Relations . . . .315
Peculiarities, Surgical Anatomy . 317, 318
External Carotid Artery.
Relations 318
Surgical Anatomy .... 319
Branches 319
Superior Tliyroid Artery.
Course and Relations .
Surgical Anatomy
. 320
. 320
Lingual Artery.
Course and Relations .
Branches
Surgical Anatomy , . . .
. 320
. 321
. 321
Facial Artery.
Course and Relations .
Branches
Peculiarities ....
Surgical Anatomy
. 321
. 322
. 323
. 324
Occipital Artery.
Course and Relations .
Branches
. 324
. 324
Posterior Auricular Artery
. 324
Ascending Pharyngeal Artery .
. 325
Temporal Artery.
Course and Relations .
Branches, Surgical Anatomy
. 325
. 326
Internal Maxillary Artery.
Course, Relations
Pecuharities ....
Branches from First Portion
Second Portion
Third Portion
. 326
. 327
. 327
. 328
. 329
CONTENTS.
Surgical Anatomy of the Tbiangles
OF THE Neck.
Anterior Triangular Space.
Inferior Carotid Triangle
Superior Carotid Triangle
Submaxillary Triangle
Posterior Triangular Space.
Occipital Triangle
Subclavian Triangle
Internal Carotid Artery.
Cervical Portion
Petrous Portion
Cavernous Portion
Cerebral Portion
Peculiarities, Surgical Anatomy
Branches ....
330
330
331
331
332
332
333
334
334
334'
334
Ophthalmic Artery . . . 334
Cerebral Branches of Internal Carotid 338
Subclavian Arteries.
First Part of Eight Subclavian Artery . 339
First Part of Left Subclavian Artery . 339
Second Part of Subclavian Artery . 340
Third Part of Subclavian Artery . 341
Peculiarities, Surgical Anatomy . 341
Branches 342
Vertebral Artery .... 343
Basilar Artery .... 344
Spinal Branches of Vertebral . 344
Cerebral Branches of Vertebral . 344
Cerebellar Branches of Vertebral . 344
. 345
. 345
. 345
. 346
. 346
. 347
. 347
. 348
. 349
. 350
. 350
. 351
. 351
. 352
. 354
. 364
. 354
. 355
. 357
. 358
. 358
. 358
Circle of Willis
Thyroid Axis .
Supra-scapular Artery
Transversalis Colli .
Internal Mammary
Superior Intercostal
Deep Cervical Artery
Surgical Anatomy of the Axilla
Axillary Artery.
First Portion
Second Portion
Third Portion
Peculiarities, Surgical Anatomy
Branches ....
Brachial Artery.
Eelations ....
Bend of the Elbow
Peculiarities of Brachial Artery
Surgical Anatomy
Branches ....
Radial Artery.
Relations ....
Deep Palmar Arch
Peculiarities, Surgical Anatomy
Branches ....
TJlnar Artery.
Relations ....
Superficial Palmar Arch
Peculiarities of Ulnar Artery
Surgical Anatomy
Branches ....
Descending Aorta
. 360
. 361
. 361
. 361
. 361
. 363
['horacic Aorta.
Relations
Surgical Anatomy
Branches
. 363
. 364
. 364
Abdominal Aorta.
Relations ....
Surgical Anatomy
Branches ....
Coeliac Axis, Gastric Artery
Hepatic Artery, Branches
Splenic Artery
Superior Mesenteric Artery
Inferior Mesenteric Artery
Supra-renal Arteries
Renal Arteries
Spermatic Arteries
Phrenic Arteries
Lumbar Arteries .
Middle Sacral Artery
Common Iliac Arteries.
Course and Relations .
Peculiarities, Surgical Anatomy .
Internal Iliac Artery.
Course and Eelations .
Peculiarities, Surgical Anatomy
Branches ....
Vesical Arteries
Hsemorrhoidal Arteries .
Uterine and Vaginal Arteries.
Obturator Artery .
Internal Pudic Artery
Sciatic Artery.
Gluteal, Ilio-lumbar, and Lateral
Sacral Arteries ....
External Iliac Artery.
366
367
367
367
368
369
370
372
373
373
373
374
374
375
375
376
377
377
378
378
378
378
378
379
381
382
Course and Eelations .
. 382
Surgical Anatomy
. 383
Epigastric Artery
. 383
Circumflex Iliac Artery
. 384
Femoral Artery.
Course and Eelations .
. 384
Scarpa's Triangle
. 384
Peculiarities of Femoral Artery
. 386
Surgical Anatomy
. 386
Branches ....
. 387
Profunda Artery
. 387
Popliteal Space
. 389
Popliteal Artery.
Course and Eelations .
. 390
Peculiarities, Surgical Anatomy
. 390
Branches ....
. 391
Anterior Tibial Artery.
Course and Eelations .
. 392
Peculiarities, Surgical Anatomy
. 393
Branches ....
. 393
Borsalis Pedis Artery.
Course and Eelations .
. 394
Peculiarities, Surgical Anatomy
. 394
Branches
. 394
CONTENTS.
Posterior Tibial Artery.
Course and Eelations .... 395
Peculiarities, Surgical Anatomy . .396
Branches .■ . . . . 396
Peroneal Artery.
Course and Eelations .... 396
Peculiarities 397
Plantar Arteries . , . .397
Pulmonary Artery .... 399
The Yeins.
General Anatomy.
Subdivision into Pulmonary, Systemic,
and Portal 400
Anastomoses of Veins .... 400
Superficial Veins, Deep Veins, or Vense
Comites 400
Sinuses, their Structure . . . 400
Structure of Veins . . . .401
Coats of Veins 401
Valves of Veins 401
Vessels and Nerves of Veins , .401
Veins of the Head and Neck.
Facial Vein 402
Temporal Vein 403
Internal Maxillary Vein . , . 403
Temporo-maxillary Vein . . .403
Posterior Auricular Vein, Occipital Vein 404
Veins of the Nech.
External Jugular Vein . . . 404
Posterior External Jugular Vein . 404
Anterior Jugular Vein . . . 404
Internal Jugular Vein . . . 405
Lingual, Pharyngeal, and Thyroid Veins 405
Veins of the Diploe .... 405
Cerebral Veins.
Superficial Cerebral Veins . . .406
Deep Cerebral Veins . . . 407
Cerebellar Veins .... 407
Sinuses of the Dura Mater.
Superior Longitudinal Sinus . . 407
Inferior Longitudinal, Straight, Lateral,
and Occipital Sinuses . . . 408
Cavernous Sinuses .... 408
Circular, Inferior Petrosal, and Trans-
verse Sinuses 409
Superior Petrosal Sinus . . . 410
Veins op the Upper Extreihty.
Superficial Veins .... 410
Deep Veins 411
Axillary Vein 412
Subclavian Vein 412
Vertebral Vein 412
Innominate Veins . . . .412
Peculiarities of .... 413
Internal Mammary Vein . . . 414
Inferior Thyroid Veins . . . 414
Superior Intercostal Veins . . .414
Superior Vena Cava .... 414
Azygos Veins 414
Spinal Veins 415
Veins of the Lower Extremity.
Internal Saphenous Vein . . .417
External Saphenous Vein . . .418
Popliteal Vein 418
Femoral Vein 418
External Iliac Vein , . . . 419
Internal Iliac Vein . . . .419
Common Iliac Vein .... 419
Inferior Vena Cava .... 420
Peculiarities .... 420
Lumbar and Spermatic Veins . . 420
Ovarian, Renal, Supra-renal Veins . 421
Phrenic Veins, Hepatic Veins . .421
Portal System of Veins.
Inferior and Superior Mesenteric Veins 421
Splenic and Gastric Veins . . 422
Portal Vein 423
Cardiac Veins.
Coronary Sinus 423
Pulmonary Veins .... 424
The Lymphatics.
General Anatomy.
Structure of, where found . . ' . 425
Subdivision into Deep and Superficial . 425
Coats of Lymphatics .... 425
Valves of Lymphatics . . . 426
Lymphatic or Conglobate Glands . 426
Structure of Lymphatic Glands . 426
Thoracic Duct 426
Eight Lymphatic Duct . . . 428
Lymphatics of Head, Face, and Neck.
Superficial Lymphatic Glands of Head 428
Lymphatics of Head . 428
of the Face . 428
Deep Lymphatics of the Face . . 428
of the Cranium . 428
Lymphatic Glands of the Neck . . 429
Superficial Cervical Glands . . 429
Deep Cervical Glands . . . 429
Superficial and Deep Cervical Lym-
phatics 429
Lymphatics of the Upper Extremity.
Superficial Lymphatic Glands . . 430
Deep Lymphatic Glands . . . 430
Axillary Glands 430
Superficial Lymphatics of Upper Ex-
tremity 431
Deep Lymphatics of Upper Extremity , 432
CONTENTS.
Lymphatics of the Lower Extremity.
Superficial Inguinal Glands . . 432
Deep Lymphatic Glands . . . 433
Anterior Tibial Gland . . .433
Deep Popliteal Glands . . . 433
Deep Inguinal Glands . . . 433
Gluteal and Ischiatic Glands . . 433
Superficial Lymphatics of Lower Ex-
tremity ..... 433
Internal Group .... 433
External Group . . . .433
Deep Lymphatics of Lower Extremity . 433
Lymphatics of Pelvis and Abdomen.
Deep Lymphatic Glands of Pelvis . 434
External Iliac Glands . . . 434
Internal Iliac Glands . . . 434
Sacral Glands .... 435
Lumbar Glands .... 435
Lymphatics of Pelvis and Abdomen . 435
Superficial Lymphatics of Wall of Ab-
domen . . 435
of Gluteal Region . .435
of Scrotum and Perineeum 435
of Penis . . .435
of Labia, Nymphse, and
Chtoris . . 435
Deep Lymphatics of Pelvis and Ab-
domen 435
Lymphatics of Bladder
of Eectum
of Uterus
of Testicle
435
435
435
436
Lymphatics of Kidney
PAGE
. 436
of Liver
. 436
Lymphatic Glands of Stomach
. 436
Lymphatics of Stomach
. 436
Lymphatic Glands of Spleen
. 437
Lymphatics of Spleen
. 437
Lymphatic System of the Intestines.
Lymphatic Glands of Small Intestines
(Mesenteric Glands) . . . 437
Lymphatic Glands of Large Intestine . 437
Lymphatics of Small Intestine (Lacteals) 437
of Great Intestine . .437
Lymphatics of Thorax.
Deep Lymphatic Glands of Thorax , 437
Intercostal Glands
. 437
Internal Mammary Glands
. 437
Anterior Mediastinal Glands
. 437
Posterior Mediastinal Glands
. 437
Superficial Lymphatics on. Eront of
Thorax ....
. 437
Deep Lymphatics of Thorax
. 437
Intercostal Lymphatics
. 437
Internal Mammary Lymphatics
. 438
Lymphatics of Diaphragm .
. 438
Bronchial Glands
. 438
Lymphatics of Lung .
. 438
Cardiac Lymphatics
. 438
Thymic Lymphatics
. 438
Thyroid Lymphatics
. 438
Lymphatics of Oesophagus .
. 438
Nervous System.
Oeneral Anatomy.
Subdivision into Cerebro-spinal Axis,
Ganglia, and Nerves . . . 439
Cerehro-Spinal Axis.
Grey Substance
White Substance
Chemical Composition
Where found.
Ganglia.
Structure
439
439
439
440
Nerves.
Subdivision into Afferent, Efferent, and
Excito-motory .... 440
Cerebro-spinal Nerves . . . 440
Sympathetic Nerve . . . . 442
The Sinnal Cord and its Membranes.
Dissection 442
442
443
443
444
444
445
445
446
446
Membranes of the Cord
Dura Mater .
Arachnoid .
Pia Mater
Ligamentum Denticulat
Spinal Cord
Fissures of Cord
Columns of Cord
Grey Matter of Cord
Mode of Arrangement of Grey and
White Matter .... 446
White Matter of Cord . , ." 447
The Brain and its Membranes.
Membranes of the Brain
Dura Mater.
Structure .....
Arteries, Veins, Nerves
Glandulse Pacchioni
Processes of the Dura Mater
Ealx Cerebri
Tentorium Cerebelli
Falx Cerebelli
Arachnoid Membrane.
Sub-arachnoid Space .
Cerebro-spinal Fluid .
Pia Mater ....
447
448
448
448
448
448
448
449
449
449
450
The Brain.
Subdivision into Cerebrum, Cerebellum,
Pons Varolii, Medulla Oblongata . 450
Weight of Brain . . . .450
■ Medulla Oblongata.
Anterior Pyramids . . . .451
Lateral Tract, and Olivary Body . 452
Restiform Bodies .... 452
Posterior Pyramids .... 452
Posterior Surface of Medulla Oblongata 452
Structure of Medulla Oblongata . . 452
of Anterior Pyramid . . 452
of Lateral Tract . . 453
of Olivary Body . . 453
of Restiform Body . . 453
Septum of Medulla Oblongata . . 454
Grey Matter of Medulla Oblongata . 454
CONTENTS.
Pons Varolii.
Structure 454
Transverse Fibres .... 454
Longitudinal Fibres .... 455
Septum 455
Cerebrum.
Upper Surface of Cerebrum . . . 455
Convolutions and Sulci . . . 455
Base of the Brain . . . .457
General Arrangement of the Parts
composing the Cerebrum . . 460
Interior of the Cerebrum . . . 460
Corpus Callosum .... 461
Lateral Ventricles .... 463
Boundaries of, and Parts forming the
Lateral Ventricles .... 463
Septum Lucidum . . . 465
Fornix 466
Velum Interpositum . . . 466
Thalami Optici . . . .467
Third Ventricle . . . .468
Anterior, Middle, and Posterior Com-
missures ..... 468
Grey Matter of Third Ventricle . . 468
Pineal Gland 468
Corpora Quadrigemina . . . 469
Valve of Vieusseus .... 469
Corpora Geniculata .... 469
Structure of Cerebrum . . . 469
1. Diverging or Peduncular Fibres . 470
2. Transverse Commissural Fibres . 470
3. LongitudinalCommissural Fibres . 470
Cerebellum.
Its Position, Size, Weight, etc. . . 470
Cerebellum, Upper Surface . . 471
Under Surface . . 471
Lobes of the Cerebellum . . . 472
Fourth Ventricle 472
Boundaries of Ventricle . . . 472
Lining Membrane, Choroid Plexus of . 473
Grey Matter of 473
Structure of the Cerebellum . . 473
Its Laminae 473
Corpus Dentatum .... 473
Peduncles of Cerebellum . . . 474
Cranial Nerves.
Subdivision into Groups . . . 475
Nerves of Special Sense . . 475
of Motion . . .475
Compound Nerves . . . 475
Nerves of Special Sense.
Olfactory Nerve 475
Optic Nerve 476
Tracts 476
Commissure . . . .477
Auditory Nerve 477
Motor Cranial Nerves.
Third Nerve (Motor Oculi) . . .477
Fourth Nerve (Trochlearis) . . . 478
Sixth Nerve (Abducens) . . . 479
Relations of the Orbital Nerves
in the Cavernous Sinus . . 479
in the Sphenoidal Fissure . . 479
in the Orbit 479
Facial Nerve
Branches of Facial Nerve
Ninth or Hypo-glossal Nerve
Compound Cranial Nerves.
Fifth Nerve
Gaserian Ganglion . . . .
Ophthalmic Nerve . . . .
Lachrymal, Frontal, and Nasal Branches
Ophthalmic Ganglion . . . .
Superior Maxillary Nerve
Spheno-palatine Ganglion
Inferior Maxillary Nerve
Auriculo-temporal, Gustatory, and In
ferior Dental Branches
Otic Ganglion
Sub-maxillary Ganglion
Eighth Pair
Giosso-pharyngeal
Spinal Accessory
Pneumogastric (Vagus)
492,
PAGE
480
481
483
485
485
485
486
487
487
489
491
493
493
494
494
494
496
497
Spinal Nerves.
Roots of the Spinal Nerves . . 501
Origin of Anterior Roots . . 501
of Posterior Roots . . 501
Ganglia of the Spinal Nerves . . 501
Anterior Branches of the Spinal Nerves 502
Posterior Branches of the Spinal Nerves 502
Cervical Nerves.
Roots of the Cervical Nerves . .502
AnteriorBranchesof theCervicalNerves 502
Cervical Plexus.
Superficial Branches of the Cervical
Plexus 503
Deep Branches of the Cervical Plexus . 505
Posterior Branches of the Cervical
Nerves 505
Brachial Plexus.
Branches above the Clavicle.
Posterior Thoracic, Supra Scapular
Branches below the Clavicle.
Anterior Thoracic, and Subscapular
Nerves
Circumflex, and Musculo-cutaneous
Nerves
Internal, and Lesser Internal Cutaneous
Nerves
Median Nerve
Ulnar Nerve
Musculo-spiral Nerve ....
Radial Nerve . . .
Posterior Interosseous Nerve
508
508
509
510
511
513
514
515
515
Dorsal Nerves.
Roots of the Dorsal Nerves . . . 516
Posterior Branches of the Dorsal Nerves 516
Intercostal Nerves . . . .516
Upper Intercostal Nerves
Intercosto-humeral Nerve
Lower Intercostal Nerves
Peculiar Dorsal Nerves
First Dorsal Nerve
Last Dorsal Nerve
616
517
517
517
517
517
XVlll
CONTENTS.
Lumbar Nerves.
Roots of Lumbar Nerves . . .518
Posterior Branches of Lumbar Nerves . 518
Anterior Branches of Lumbar Nerves . 518
Lumbar Plexus.
Branches of Lumbar Plexus . .519
Ilio-hypogastric Nerve . . . 519
Ilio-inguinal, and Geuito-crural Nerves 520
External Cutaneous, and Obturator
Nerves ...... 520
Accessory Obturator Nerve . .522
Anterior Crural Nerve . . .522
Branches of Anterior Crural . . 522
Middle Cutaneous .... 523
Internal Cutaneous, Long Saphenous . 523
Muscular and Articular Branches . 524
Sacral and Coccygeal Nerves.
Boots of, Origin of .... 524
Posterior Sacral Nerves . . . 524
Anterior Sacral Nerves . . . 524
Posterior Branch of Coccygeal Nei've . 524
Anterior Branch of Coccygeal Nerve . 525
Sacral Plexus.
Superior Gluteal Nerve . . . 525
Pudic, and Small Sciatic Nerves . 526
Great Sciatic Nerve .... 528
Internal Popliteal Nerve . ■ . . 528
Posterior Tibial Nerve . . . 529
Plantar Nerves 529
External Popliteal or Peroneal Nerve . 530
Anterior Tibial Nerve . . . 530
Musculo-cutaneous Nerve . . . 530
Sympathetic Nerve.
Subdivision of, into Parts . . . 532
Branches of the Ganglia, General De-
scription of .... . 532
Cervical Portion of the Sympathetic.
Superior Cervical Ganglion.
Carotid and Cavernous Plexuses . 534
Middle Cervical Ganglion . . 535
Inferior Cervical Ganglion. . . 535
Cardiac Nerves.
Superior, Middle, and Inferior Cardiac
Nerves 536
Deep Cardiac Plexus .... 536
Superficial Cardiac Plexus . . . 537
Anterior and Posterior Coronary Plexus 537
Thoracic Part of the Sympathetic.
Great Splanchnic Nerve . . . 537
Lesser Splanchnic Nerve . . . 538
Smallest Splanchnic Nerve . . . 538
Epigastric or Solar Plexus . . . 538
Semilunar Ganglia .... 638
Phrenic, Supra-renal, and Eenal Plexuses 538
Spermatic, Coeliac, and Gastric Plexuses 539
Hepatic, Splenic, and Superior Mesen-
teric Plexuses 539
Aortic, and Inferior Mesenteric Plexuses 539
Lumbar Portion of Sympathetic. 540
Pelvic Portion of Sympathetic . . 540
Hypogastric Plexus .... 540
Inferior Hypogastric or Pelvic Plexus . 540
Inferior Hsemorrhoidal Plexus . . 540
Vesical Plexus 540
Prostatic Plexus 541
Vaginal Plexus 541
Uterine Nerves 541
Organs of Sense.
Skin.
Derma, or True Skin .... 542
Corium ..... 543
Papillary Layer .... 543
Epidermis or Cuticle . . . 543
Vessels and Nerves of the Skin . 544
Appendages op the Skin.
Nails , 545
Hairs 645
Sebaceous and Sudoriferous Glands . 546
Tongue.
Papillse of. Structure of Papillae . 548, 549
Folhcles, and Mucous Glands . , 549
Fibrous Septum of ... . 549
Muscular Fibres of . . . .549
Arteries and Nerves of . . .550
Nose.
Cartilages of, Muscles .... 551
Skin, Mucous Membrane . . . 552
Arteries, Veins, and Nerves . . 552
Nasal Fossce.
Mucous Membrane of . . . . 552
Peculiarities of, in Superior, Middle,
and Inferior Meatuses . . 552, 553
Arteries, Veins, and Nerves of Nasal
Fossse 553
Eye.
Situation, Form of ... - 553
Tunics of. Sclerotic .... 554
Cornea, Structure of Cornea . . 555
Choroid, Structure of Choroid . .557
Ciliary Processes, Iris . . . 558
Membrana Pupillaris, Ciliary Ligament 559
Ciliary Muscle 559
Retina 559
Structure of Retina .... 560
Jacob's Membrane . . . 560
Granular Layer . . . .561
Nervous Layer .... 561
Radiating Fibres of the Retina . 561
Arteria Centralis Retinae . . .561
Structure of Retina, at Yellow Spot . 561
CONTENTS.
Humours of the Eye.
Aqueous Humour .... 561
Anterior Chamber . . .561
Posterior Chamber . . . 562
Vitreous Body 562
Crystalhne Leus and its Capsule . 562
Changes produced in the Lens by Age . 563
Suspensory Ligament of Lens . .563
Canal of Petit 563
Vessels of the Globe of the Eye . 563
Arteries, Veins, and Nerves of Eyeball . 564
Appendages of the Ete.
Eyebrows 564
Eyehds 564
Structure of the Eyelids . . . 564
Tarsal Cartilages . . . .564
Meibomian Glands . . . .565
Eyelashes 565
Conjunctiva, and Caruncula Lachry-
malis 566
Lachrymal Apparatus . 566
Lachrymal Gland . . . .667
Canals . . . .567
Sac 567
Nasal Duct 567
Ear.
Pinna or Auricle .... 567
Structure of Auricle .... 568
Ligaments of the Pinna . . . 668
PAGE
Muscles of the Pinna .... 669
Arteries, Veins, and Nerves of the Pinna 570
Auditory Canal 570
Middle Ear or Tympanum.
Eustachian Tube .... 573
Membrana Tympani .... 573
Structure of 573
Ossicles of the Tympanum . . . 574
Ligaments of the Ossicula . . . 574
Muscles of the Tympanum . . 575
Mucous Membrane of Tympanum . 575
Arteries, Veins, and Nerves of Tym-
panum 576
Internal Ear or Labyrinth.
Vestibule 576
Semicircular Canals .... 577
Superior Semicircular Canal . 577
Posterior Semicircular Canal . 577
External Semicircular Canal . 578
Cochlea 578
Central Axis of, or Modiolus . 578
Spiral Canal of ... . 578
Lamina Spiralis of . . .579
Scala Tympani, Scala Vestibuli . . 579
Membranous Labyrinth . . . 580
Utricle and Sacculus .... 580
Membranous Semicircular Canals . 580
Vessels of the Labyrinth . . .681
Auditory Nerve, Vestibular Nerve,
Cochlear Nerve .... 581
VISCERA.
Organs of Digestion and their Appendages.
Alimentary Canal . . . .682
Its Subdivisions .... 682
The Mouth 682
The Lips . . . . . .582
The Cheeks 683
The Gums 583
Teeth.
General Characters of ... 584
Permanent Teeth ..... 686
Incisors, Canine, Bicuspid, Molars . 585
Temporary or Milk Teeth . . .586
Structure of the Teeth . . . 687
Ivory or Dentine, Chemical Composition 687
Enamel, Cortical Substance . . 588
Development of the Teeth . . 688
of the Permanent Teeth . 690
Growth of the Teeth . . .690
Eruption of the Teeth . . .590
Palate.
Hai*d Palate 591
Soft Palate 591
Uvula, Pillars of the Soft Palate . 592
Mucous Membrane, Aponeurosis, and
Muscles of Soft Palate . . .692
To7isils.
Arteries, Veins, and Nerves of Tonsils .
Salivary Glands.
Parotid Gland,
Steno's Duct ....
Vessels and Nerves of Parotid Gland
593
694
Suhmaonllary Gland.
"Wharton's Duct . . . .594
Vessels and Nerves of Submaxillary
Gland 594
tSuhlingual Gland.
Vessels and Nerves of ... 694
Structure of Salivary Glands . . 594
Pharynx.
Structure of ..... 595
CEsophagus . . . . .595
Relations, Surgical Anatomy, and Struc-
ture of ..... . 596
592
Abdomen.
Boundaries
Apertures of. Regions .
Peritoneum.
Reflections traced .
Foramen of Winslow .
Lesser Omentum .
Great Omentum .
597
597
599, 600
. 600
. 601
. 601
CONTENTS.
PAGB.
Gastro-splenic Omentum . . . 601
Mesentery 601
Mesocsecum, Mesocolon . . . 602
Siomach.
Situation 602
Splenic end, Pyloric end . . . 602
Cardiac and Pyloric Orifices . . . 602
Greater and Lesser curvatures . . 602
Surfaces 603
Ligaments of . . . . • 603
Alterations in Position .... 603
Pylorus 604
Structure of Stomach .... 604
Serous and Muscular Coats . . . 604
Mucous Membrane .... 605
Gastric Follicles 605
Vessels and Nerves of Stomach . .606
Small Intestines.
Duodenum 606
Ascending portion .... 606
Descending portion . . . 606
Transverse portion . . . 606
Vessels and Nerves of Duodenum . 607
Jejunum 607
Ileum 607
607
607
607
607
608
608
608
Structure of Small Intestines
Serous, Muscular and Cellular Coats
Mucous Membrane
Epithelium and Valvulse Conniventes
Villi — their Structure .
Simple Follicles, Duodenal Glands
Solitary Glands, Aggregate Glands
Large Intestine.
Csecum ....
Appendix Ceeci Vermiformis
Ileo-cEecal Valve
Colon
Ascending
Transverse
Descending
Sigmoid Flexure .
Eectum ...
Upper Portion
Middle Portion
Lower Portion
Structure of Large Intestine
Serous and Muscular Coats .
Cellular and Mucous Coats .
Epithelium, Simple Follicles and
tary Glands of Large Intestine
Soli-
609
609
610
611
611
611
611
611
611
612
612
612
612
612
613
613
Liver.
Size, weight, position of
Its Surfaces and Borders
Changes of Position
Ligaments.
Longitudinal, Lateral, Coronary .
Eound Ligament ....
Fissures.
Longitudinal 6] 5
Fissure of Ductus Venosus, Portal
Fissure 615
Fissures for Gall Bladder and Vena
Cava 616
613
614
614
614
615
Lobes.
Eight, Left ....
616
Quadratus, Spigelii, Caudatus
617
Vessels of Liver .
617
Lymphatics, Nerves
617
Structure of Liver
617
Serous and Fibrous Coats
617
Lobules
617
Hepatic Cells, Biliary Ducts,
Portai
Vein ....
618
Hepatic Artery, Hepatic Veins
619
Gall Bladder.
Structure 620
BiHary Ducts 620
Hepatic, Cystic, and Common Cho-
ledic Ducts 620
Structure of Biliary Ducts . . 621
Pancreas.
Dissection 621
Relations 621
Duct. Structure . . . .622
Vessels and Nerves .... 623
Spleen.
Eelations 623
Size and Weight 623
Structure of Serous and Fibrous Coats 623
Propef Substance . . . .624
Malpighian Corpuscles . . . 625
Splenic Artery, distribution . . . 625
Capillaries of Spleen .... 627
Veins of Spleen 627
Lymphatics and Nerves . . .627
THOEAX.
Boundaries of 628
Superior Opening, Base . . . 628
Parts passing through Upper Opening 628
Pericardium.
Structure . .
Fibrous layer. Serous Layer
629
629
Heart.
Position, Size 629
Subdivision into Four Cavities . .629
Circulation of Blood in Adult . . 629
Auriculo-ventricular, and Ventricular
Grooves 630
Right Auricle.
Openings ....
Valves ....
Eelics of Foetal Structure
Musculi Pectinati .
. 631
. 631
. 632
. 632
Right Ventricle.
Openings 632
Tricuspid and Semilunar Valves . . 633
Chordse Tendineae and Columnse Carneas 633
Le,ft Auricle.
Sinus and Appendix .... 634
Openings, Musculi Pectinati . . 634
Jjcft Ventricle.
Openings 635
Mitral and Semilunar Valves . . 635
Endocardium ..... 635
CONTENTS.
Structure of Heart.
Fibrous Rings
. 636
Muscular Structure
. 636
of Auricles .
. 636
of Ventricles
. 636
Vessels and Nerves of Heart
. 637
Peculiarities in Vascular System of
Foetus 637
Foramen Ovale, Eustachian Valve . 637
Ductus Arteriosus .... 638
Umbilical or Hypogastric Arteries . 639
Foetal Circulation 639
Changes in Vascular System at Birth . 640
Organs of Voice and Respiration.
The Larynx.
Cartilages of the Larynx . . . 641
Thyroid Cartilage . . . .641
Cricoid and Arytenoid Cartilages . 642
Cartilages of Santorini, and Wris-
berg 643
Epiglottis. Its structure . . 643
Ligaments of the Larynx . . . 643
Ligaments connecting the Thyroid
Cartilage with the Os Hyoides . 643
Ligaments connecting the Thyroid Car-
tilage with the Cricoid . . . 644
Ligaments connecting the Arytenoid
Cartilages to the Cricoid . . . 644
Ligaments of the Epiglottis . . 644
Interior of the Larynx . . ,644
Cavity of the Larynx .... 644
Glottis 644
False Vocal Cords . . . .645
True Vocal Cords . . . .645
Ventricle of Larynx, Sacculus Laryngis 646
Muscles of Larynx
Crico-thyroid ....
Crico-arytsenoideus posticus .
lateralis .
Th yro-arytsenoideus
Muscles of the Epiglottis
Thyro-epiglottideus
Arytseno-epiglottideus, superior
inferior
Actions of Muscles of Larynx
Mucous Membrane of Larynx
Glands, Vessels and Nerves of
Trachea.
Eelations
Bronchi
646
646
646
646
646
647
647
647
647
647
648
648
648
649
Structure of Trachea .... 650
Surgical Anatomy of Laryngo-tracheal
Region 651
The Pleurce.
Reflections 653
Vessels and Nerves . . . .653
Mediastinum.
Anterior Mediastinum . . . .653
Middle Mediastinum .... 654
Posterior Mediastinum .... 654
The Lungs.
Surfaces, Lobes 655
Root of Lung 655
Weight, Colour, and Properties of Sub-
stance of Lung 656
Structure of Lung . , . .656
Serous Coat, and Subserous Areolar
Tissue 656
Parenchyma and Lobules of Lung . 656
Bronchi, arrangement of Branches in
Substance of Lung .... 656
Structure of smaller Bronchial Tubes . 656
The Air Cells
Pulmonary Artery
Pulmonary Capillaries and Veins
Bronchial Arteries and Veins
Lymphatics and Nerves of Lung
Thyroid Gland.
Structure ....
Vessels and Nerves
Chemical Composition .
Thymus Qland.
Structure ....
Vessels and Nerves
Chemical Composition
657
657
657
657
657
658
659
659
659
658
659
The Urinary Organs.
Kidneys.
Relations ....
Dimensions, Weight
Cortical Substance
Medullary Substance
Minute Structure
Malpighian Bodies
Ureter, Pelvis, Infundibula .
Renal Artery, Renal Veins .
Lymphatics and Nerves
Ureters.
Situation, Course, Relations .
Structure ....
Relations
Swpra^Renal Capsules.
660
660
660
661
661
662
662
662
663
663
663
664
Structure
Vessels and Nerves
Pelvis.
Boundaries and Contents
Bladder.
Shape, Position, Relations
Subdivisions .
Ligaments
Structure
Interior of Bladder
Vessels and Nerves
Male Urethra.
Structure
664
664
665
665
666
666
667
667
668
669
CONTENTS.
Male Generative Organs.
i
Prostate Gland
PAGE
. 671
Structure
. 671
Vessels and Nerves
. 672
Prostatic Secretion
. 672
Cowper's Glands .
. 672
Penis.
Root
Glans Penis .
Body
Corpora Cavernosa
Structure
Corpus Spongiosum
The Bulb
Structure of Corpus Spongiosum
Erectile Tissue
Arteries of the Penis
Lymphatics of the Penis
Nerves of the Penis
672
672
672
673
673
673
673'
674
674
674
674
674
The Testes and their Coverings.
Scrotum 675
Other Coverings of the Testis . . 675
Vessels and Nerves of the Coverings of
the Testis 675
I
Spermatic Cord.
Its Composition 676
Relations of in Inguinal Canal . . 676
Arteries of the Cord . . . .676
Veins of the Cord
. 676
Lymphatics and Nerves of the Cord . 676
Testes.
Form and Situation
. 676
Size and Weight
. 677
Coverings
. 677
Tunica Vaginalis .
. 677
Tunica Albuginea .
. 677
Mediastinum Testis
. 677
Tunica Vasculosa „
. 677
Structure of Testis
. 678
Lobules of the Testis .
. 678
Number, Size, Shape, Positior
1 . .678
Structure of the Lobuli Test]
s . .678
Tubuli Seminiferi .
. 678
Arrangement in the Lobuli
. 678
in the Mediasti
num. . 678
in the Epididy
mis . . 678
Vasculum Aberrans
. 678
Vas Deferens, Course, Relatio
ns . . 679
Structure
. 679
Vesicute Seminales
. 679
Form and Size
. 679
Relations
. 680
Structure
. 680
Ejaculatory Ducts .
. 680
Structure of
. 680
The Semen .
. 680
Descent of the Testes .
. .680
Gubernaculum Testis
. 681
Female Organs of Greneration.
Mons Veneris, Labia Majora . . . 682
Labia Minora, Clitoris, Meatus Urinarius 683
Hymen, Glands of Bartholine . . 683
Bladder 684
Urethra 684
Rectum 685
Vagina.
Relations
. 685
Structure
. 685
Uterus.
Situation, Form, Dimensions
. 686
Fundus, Body and Cervix
. 686
Ligaments
. 686
Cavity of the Uterus
. 686
Structure . . ' . . .
. 687
Vessels and Nerves
. 687
Its Form, Size, and Situation . . 688
in the Foetus . . .688
at Puberty . . . .688
during and after Menstruation 688
after Parturition . . . 688
in Old Age . . . . 688
Appendages of the Uterus.
FaUopian Tubes ... .688
Structure 688
Ovaries 688
Structure 689
Graafian Vesicles . . . 689
Ligament of the Ovary . . . 690
Round Ligaments .... 690
Vessels and Nerves of Appendages . 690
Mammary Olands.
Structure of Mamma . . . 691
Vessels and Nerves . . . .691
Surgical Anatomy of Inguinal Hernia.
Dissection 692
Superficial Fascia .... 692
Superficial Vessels and Nerves . .692
Deep Layer of Superficial Fascia . 692
Aponeurosis of External Obhque . 693
External Abdominal Ring . . . 694
Pillars of the Ring .... 694
Intercolumnar Fibres .
. 694
Fascia •
. 694
Poupart's Ligament
. 695
Gimbernat's Ligament .
. 695
Internal Oblique Muscle
. 695
Triangular Ligament
. 695
Cremaster ....
. 695
CONTENTS.
Transversalis Muscle
Spermatic Canal
Fascia Transversalis
Internal Abdominal Ring
Subserous Ai-eolar Tissue
Epigastric Artery
Peritoneum
PAGE
696
, 696
. 696
. 697
. 697
, 698
, 698
Inguiyial Hernia,
Oblique Inguiual Hernia . . . 698
Course and Coverings of Oblique Hernia 698
Seat of Stricture . . . .698
Scrotal Hernia
Bubonocele
Congenital Hernia .
Infantile Hernia .
PAGE
. 699
. 699
. 699
. 699
Direct Inguinal Hernia.
Course and Coverings of the Hernia . 699
Seat of Stricture 699
Incomplete Direct Hernia . . . 699
Comparative Frequency of Oblique and
Direct Hernia 700
Diagnosis of Oblique and Direct -Hernia 700
Surgical Anatomy of Femoral Hernia.
Dissection ....
. 700
Crural Arch
. 703
Superficial Fascia
. 700
Gimbernat's Ligament
. 704
Cutaneous Vessels
. 700
Crural Sheath
. 704
Internal Sapliena Vein
. 700
Deep Crural Arch
. 705
Superficial Inguinal Glands
. 701
Crural Canal
. 705
Cutaneous Nerves
. 701
Femoral or Crural Ring
. 705
Deep Layer of Superficial Fascia
. 701
Position of Parts around the Ring . 705
Cribriform Fascia
. 702
Septum Crurale
. 706
Fascia Lata ....
. 702
Descent of Femoral Hernia
. 707
Iliac Portion .
. 702
Coverings of Femoral Hernia
. 707
Pubic Portion
. 703
Varieties of Femoral Hernia
. 707
Saphenous Opening
. 703
Seat of Stricture
. 708
Surgical Anatomy of Perinseum and IscMo-Rectal Region.
Ischio-Rectal Region.
Dissection .
Superficial Fascia
External Sphincter
Internal Sphincter
Ischio-rectal Fossa
Position of Parts contained in
709
709
710
710
710
711
Perinceum.
Boundaries, and Extent . . .711
Superficial Layer of Superficial Fascia . 711
Deep Layer of Superficial Fascia . 711
Course taken by the Urine in Rupture
of the Urethra . . . .712
Muscles of the Perinceum {Male).
Accelerator Urinee .... 712
Erector Penis 713
Transversus Perinsei . . . .713
Superficial Perinseal Vessels and Nerves 713
Transversus Perinaei Artery . . 714
Muscles of the Perinceum {Female).
Sphincter Vaginae . . . .714
Erector Clitoridis . . . .714
Transversus Perin^i . . . .714
Surgical Anatomy of the Triangles of the Neck .... 320-2
,, Axilla 348
,, Bend of Elbow 354
J, Scarpa's Triangle 384
„ Popliteal Space . 389
„ Laryngo-Traclieal Region. ... esi
Compressor Urethrse .
. 714
Sphincter Ani
. 714
Levator Ani
. 715
CoccygEeus
. 715
Deep Perinseal Fascia ,
. 715
Anterior Layer
. 715
Posterior Layer
. 715
Parts between the two Layers
. 715
Compressor Urethree .
. 715
Cowper's Glands
. 715
Pudic Vessels and Nerves
. 715
Artery of the Bulb
. 715
Levator Ani
. 715
Relations, Actions
. 716
Coccygeus, Relations, Actions
. 716
Position of Viscera at Outlet of P
3lvis. 716
Parts concerned in the Operati
on of
Lithotomy
. 717
Parts divided in the Operation
. 718
Parts to be avoided in the Operat
ion . 718
Abnormal Course of Arteries i
n the
Perinseum
. 719
Pelvic Fascia
. 719
Obturator Fascia
. 720
Recto-vesical Fascia .
. 720
i
LIST OF ILLUSTRATIONS.
RS" The Illustrations when copied from any other work, have tlie author's name
affixed; when no such acknowledgment is made, the drawing is to be
considered original.
Osteology.
1. A Cervical Vertebra .
2. Atlas
3. Axis
4. A Dorsal Vertebra .
5. Peculiar Dorsal Vertebrae .
6. A Lumbar Vertebra .
7 to 12. Development of a Vertebra
13. Sacrum, anterior surface ,
14. Sacrum, posterior surface ,
1-5. Development of Sacrum .
16. Coccyx, anterior and posterior surfaces
17. Lateral View of Spine
18. Occipital Bone, outer surface
19. Occipital Bone, inner surface
20. Occipital Bone, development of
21. Parietal Bone, external surface .
22. Parietal Bone, inner surface
23. Frontal Bone, outer surface
24. Frontal Bone, inner surface
25. Temporal Bone, outer surface .
26. Temporal Bone, inner surface .
27. Temporal Bone, Petrous portion
28. Temporal Bone, development of
29. Sphenoid Bone, superior surface
30. Sphenoid Bone, anterior surface
31. Sphenoid Bone, posterior surface
32. Plan of the Development of Sphenoid
33. Ethmoid Bone, outer surface
34. Perpendicular plate of Ethmoid, enlarged
35. Nasal Bone, outer surface .
36. Nasal Bone, inner surface .
37. Superior Maxillary Bone, outer surface
38. Superior MaxiUary Bone, inner surface
39. Development of Superior Maxillary Bone
40. Lachrymal Bone, outer surface .
41. Malar Bone, outer surface
42. Malar Bone, iuner surface
43. Palate Bone, internal view, enlarged .
44. Palate Bone, posterior view
45. Inferior Turbinated Bone, inner surface
46. Inferior Turbinated Bone, outer surface
Quain
Quain
Qiiain
Quain
6
6
7
8
9
10
11
13
14
15
16
17
19
21
22
23
24
25
26
28
29
31
32
33
33
35
36
37
37
39
39
41
42
44
45
44
46
47
48
49
49
XXVI
LIST OF ILLUSTRATIONS.
FIG.
47. Vomer
48. Lower Jaw, outer surface .
49. Lower Jaw, inner surface .
50. Base of Skull, inner surface
51. Base of Skull, external surface .
52. Anterior Region of Skull .
53. Nasal Fossae, outer wall
54. Nasal Fossae, inner wall or septum
55. Hyoid Bone, anterior surface
56. Sternum and Costal Cartilages, anterior surface
57. Sternum, posterior surface
58 to 61. Development of Sternum
62. A Rib
63. Vertebral Extremity of a Rib .
64 to 68. Peculiar Ribs . . . .'
69. Os Innominatum, external surface
■ 70. Os Innominatum, internal surface
71. Plan of Development of Os Innominatum
72. Left Clavicle, superior surface
73. Left Clavicle, inferior surface
74. Left Scapula, anterior surface, or venter
75. Left Scapula, posterior surface, or dorsum
76. Plan of the Development of the Scapula
77. Left Humerus, anterior view
78. Left Humerus, posterior surface
79. Plan of the Development of the Humerus
80. Bones of the Left Fore-arm, anterior surface
81. Bones of the Left Fore-arm, posterior surface
82. Plan of the Development of the Ulna
83. Plan of the Development of the radius
84. Bones of the Left-hand, dorsal surface
85. Bones of the Left-hand, palmar surface
86. Plan of the Development of the Hand
87. Right Femur, anterior surface .
88. Right Femur, posterior surface
89. Plan of the Development of the Femur
90. Right Patella, anterior surface
91. Right Patella, posterior surface
92. Tibia and Fibula, anterior surface
93. Tibia and Fibula, posterior surface .
94. Plan of the Development of the Tibia
95. Plan of the Development of the Fibula
96. Bones of the Right Foot, dorsal surface
97. Bones of the Right Foot, plantar surface
98. Plan of the Development of the Foot
PAGE
60
Quain
Articulations.
99. Vertical-Section of Two Vertebrae and their Ligaments, front view
100. Occipito-Atloid and Alto-axoid ligaments, front view
101. Occipito-Atloid and Alto-axoid ligaments, posterior view .
102. Articulation between Odontoid Process and Atlas . . . Arnold
103. Occipito-Axoid, and Alto-axoid Ligaments
104. Temporo-Maxillary Articulation, external view .
105. Temporo-Maxillary Articulation, internal view .
106. Temporo-Maxillary Articulation, vertical section
107. Costo-Vertebral and Costo-Transverse Articulations, anterior view
103. Costo-Transverse Articulation Arnold
LIST OF ILLUSTRATIONS. xxvii
no. PAr.i!.
109. Costo-Sternal, Costo-Xiphoid and Intercostal Articulations, front view . 150
110. Articulations of Pelvis and Hip, front view 152
111. Articulations of Pelvis and Hip, back view 153
112. Vertical Section of Symphysis pubis : 156
113. Stern o-Clavicular Articulation 157
114. Shoulder Joint, Scapulo-Clavicular Articulation and proper Ligaments of
Scapula 159
115. Left Elbow Joint, shewing anterior and internal Ligaments . . . .161
116. Left Elbow Joint, shewing posterior and external Ligaments . . . .162
117. Ligaments of Wrist and Hand, anterior view .... Arnold 165
118. Ligaments of Wrist and Hand, posterior view .... do. 165
119. Vertical Section of Wrist, shewing the Synovial Membranes . . . .168
120. Articulations of the Phalanges 170
121. Left Hip Joint, laid open 171
122. Eight Knee Joint, anterior view 172
1 23. Right Knee Joint, posterior view 173
124. Right Knee Joint, shewing internal Ligaments 174
125. Head of Tibia, with semi-lunar Cartilages seen from above . . . .175
126. Ankle Joint, Tarsal, and Tarso-Metatarsal Articulations, internal view . . 178
127. Ankle Joint, Tarsal, and Tarso-Metatarsal Articulations, external view . . 179
128. Ligaments of Plantar surface of the Foot 181
129. Synovial Membranes of the Tarsus and Metatarsus . . . Arnold 182
Muscles and Fascise.
130. Plan of Dissection of Head, Face and Neck 188
131. Muscles of the Head, Face and Neck 189
132. Muscles of the right Orbit 193
133. The relative position and attachment of the Muscles of the left Eyeball . 193
134. The Temporal Muscle 1^)9
135. The Pterygoid Muscles 200
136. Muscles of the Neck and boundaries of the Triangles 204
137. Muscles of the Neck, anterior view Quain 206
138. Muscles of the Tongue, left side 209
139. Muscles of the Pharynx, external view 211
140. Muscles of the Soft Palate 213
141. The Prevertebral Muscles • Quain 216
142. Plan of Dissection of the Muscles of the Back 216
143. Muscles of the Back — first, second, and part of the third layers Quain 219
144. Muscles of the Back — deep layers 224
145. Plan of Dissection of Abdomen 230
146. The External Oblique Muscle £31
147. The Internal Oblique Muscle 232
148. The Transversalis, Rectus and Pyramidalis 234
149. Transverse Section of Abdomen in Lumbar Region . . . Quain 235
150. The Diaphragm, under surface 239
151. Plan of Dissection of Upper Extremity 242
152. Muscles of the Chest and Front of the Arm, superficial view . . . . 243
153. Muscles of the Chest and Front of the Arm, with the boundaries of the
Axilla 245
154. Muscles on the Dorsum of the Scapula and the Triceps 249
155. Front of the left Fore-arm, superficial muscles 254
156. Front of left Fore-arm, deep muscles 257
157. Posterior surface of Fore-arm, superficial muscles 259
158. Posterior surface of the Fore-arm, deep muscles 262
159. Muscles of the left Hand, palmar surface . . . . ' . . . . 265
160. Dorsal Interossei of the left Hand 267
IGl. Palmar InteroESci of Left Hand 268
xxviii LIST OF ILLUSTRATIONS.
FIG.
162. Fracture of the Middle of the Clavicle
163. Fracture of the Surgical Neck of the Humerus
164. Fracture of the Humerus above the Condyles .
165. Fracture of the Olecranon
166. Fracture of the Shaft of the Radius ....
167. Fracture of the lower end of the Eadius ,
168. Plan of Dissection of Lower Extremity, front view .
169. Muscles of Iliac and Anterior Femoral Regions
170. Muscles of the Internal Femoral Region ,
171. Plan of Dissection of Lower Extremity, posterior view
172. Muscles of the Gluteal and Posterior Femoral Regions
173. Muscles of the front of the Leg ....
174. Muscles of the back of Leg, superficial layer
175. Muscles of the back of the Leg, deep layer
176. Muscles of the sole of the Foot, first layer.
1 77. Muscles of the sole of the Foot, second layer
178. Muscles of the sole of the Foot, third layer
179. The Dorsal Interossei
180. The Plantar Interossei
181. Fracture of the Neck of the Femur within the Capsular Ligi
182. Fracture of the Femur below the Trochanter Minor
183. Fracture of the Femur above the Condyles
184. Fracture of the Patella
185. Oblique fracture of the shaft of the Tibia .
186. Fracture of the Fibula, with dislocation of the Tibia inwards
ament
Hind
do.
do.
do.
do.
do.
Quain
Hind
do.
do.
do.
do.
do.
PA rue "
269
270
271
271
272
273
276
277
281 1
284
285
290
292
294
300
301
302
303
303
304
304
305
305
306
306
■
Arteries.
187. The Arch of the Aorta and its branches .
188. Plan of the branches of the Arch of the Aorta .
189. Surgical anatomy of the Arteries of the Neck .
190. Plan of the branches of the External Carotid .
191. The Arteries of the Face and Scalp ....
192. The Internal Maxillary Artery, and its branches
193. Plan of the branches of the Internal ]\Iaxillary Artery
194. The Internal Carotid and Vertebral Arteries
195. The Ophthalmic Artery and its branches .
196. The Arteries at the base of the Brain
197. Plan of the branches of the Right Subclavian Artery
198. The Scapular and Circumflex Arteries
199. The AsiUary Artery and its branches
200. The Surgical Anatomy of the Brachial Artery .
201. The Surgical Anatomy of the Radial and Ulnar Arteries
202. Ulnar and Radial Arteries, deep view
203. Arteries of the back of the Fore-Arm and Hand
204. The Abdominal Aorta and its branches . . . -
205. The Cceliac Axis and its branches ....
206. The Ccehac Axis and its branches, the Stomach having been raised, and the
Transverse Mesocolon removed ....
207. The Superior Mesenteric Artery and its branches .
208. The Inferior Mesenteric Artery and its branches
209. Arteries of the Pelvis
210. The Arteries of the Gluteal and Posterior Femoral Regions
211. Surgical Anatomy of the Femoral Artery ....
212. The Popliteal, Posterior Tibial, and Peroneal Arteries
213. Surgical Anatomy of the Anterior Tibial and Dorsalis Pedis Arteries
214. The Plantar Arteries, superficial view
215. The Plantar Arteries, deep view .....
309
309
316
316
322
327
327
333
335
337
343
346
348
353
356
359
362
366
368
367
371
372
375
381
385
391
393
398
398
do.
430
do.
431
do.
432
LIST OF ILLUSTRATIONS.
Veins.
F!0. PAGK,
216. Veins of the Head and Neck 402
217. Veins of the Diploe, as displayed by the removal of the outer ) „ ,
table of the Skull } i^reschet 4Ub
218. Vertical Section of the Skull, shewing the Sinuses of the Dura Mater . . 407
219. The Sinuses at the Base of the Skull 409
220. The Superficial Veins of the Upper Extremity 410
221. The VenseCavae and Azygos Veins, with their Formative Branches . . . 413
222. Transverse Section of a Dorsal Vertebra, shewing the Spinal Veins Breschet 416
223. VerticalSectionof two DorsalVertebrse, shewing the Spinal Veins Breschet 416
224. The Internal Saphenous Vein and its Branches 417
225. The External, or short Saphenous Vein 418
226. The Portal Vein and its Branche Quaiii 422
Lympliatics.
227. The Thoracic and Right Lymphatic Ducts 427
228. The Superficial Lymphatics and Glands of the Head, Face, and ) ,, ■ ^o^
-vj ^ > Jilciscci-Cjni 429
229. The Deep Ljinphatics and Glands of the Neck and Thorax
230. The Superficial Lymphatics and Glands of the Upper Extremity
231. The Superficial Lymphatics and Glands of the Lower Extremity
232. The Deep Lymphatic Vessels and Glands of the Abdomen and )
T5 1 • \ do. AM
relvis \
ISTervous System,
233. The Spinal Cord and its Membranes . 443
234. Transverse Section of the Sjainal Cord and its Membranes . Arnold 443
235. Spinal Cord, side view. Plan of the Fissures and Columns . Quain 445
236. Transvers3 Sections of the Cord Arnold 447
237. Medulla Oblongata and Pons Varolii, anterior surface 451
238. Medulla Oblongata and Pons Varolii, posterior surface 452
239. Transverse Section of Medulla Oblongata .... Arnold 453
240. The Columns of the Medulla Oblongata, and their Connection ) Altered fr-om
with the Cerebrum and Cerebellum \ Arnold ''
241. Upper Surface of the Brain, the Pia Mater having been removed . . . 456
242. Base of the Brain 458
243. Section of the Brain, made on a level with the Corpus Callosum , . . 461
244. The Lateral Ventricles of the Brain 462
245. The Fornix, Velum Interpositum, and Middle or Descending Horn of the
Lateral Ventricle 4G4
246. The Third and Fourth Ventricles 467
247. The Cerebellum, upper surface 471
248. The Cerebellum, under surface .......... 471
249. The Cerebellum, vertical section Arnold 473
Cranial Nerves.
250. The Optic Nerves and Optic Tracts ....:.... 476
251. Course of the Fibres in the Optic Commissure . . . , Bowman 477
252. Nerves of the Orbit, seen from above After Arnold 478
XXX
LIST OF ILLUSTRATIONS.
253. Nerves of the Orbit and Ophthalmic GangHon, side view
254. The Course and Connections of the Facial Nerve in the Tem-
poral Bone
255. The Nerves of the Scalp, Face, and Side of the Neck
256. The Hypoglossal Nerve, Cervical Plexus, and their Branches .
257. Distribution of the Second and Third Divisions of the Fifth
Nerve and Sub-Maxillary Ganglion
258. The Spheno-Palatine Ganglion and its Branches
259. The Otic GangUon and its Branches
260. Origin of the Eighth Pair, their Ganglion and Communications .
261. Course and Distribution of the Eighth Pair of Nerves
After Arnold 479
After Bidder 480
. 482
. 484
After Arnold 488
. 490
After Arnold 494
Bendz. 494
. 495
Spinal 'Nerves.
262. Plan of the Brachial Plexus
263. Cutaneous Nerves of Right Upper Extremity, anterior view
264. Cutaneous Nerves of Right Upper Extremity, posterior view
265. Nerves of the Left Upper Extremity, front view
266. The Supra-Scapular, Circumflex, and Musculo-Spiral Nerves
267. The Lumbar Plexus and its Branches Alterei
268. The Cutaneous Nerves of Lower Extremity, front view .
269. Nerves of the Lower Extremity, front view
270. Cutaneous Nerves of Lower Extremity, posterior view
271. Nerves of the Lower Extremity, posterior view
272. The Plantar Nerves
273. The Sympathetic Nerve
dfr
. 507
. 509
. 610
. 512
. 514
Quain 519
. 521
. 521
. 527
. 527
629
. 533
274.
275.
276.
277.
278.
279.
280.
281.
282.
283.
284.
285.
286.
287.
288.
289.
290.
291.
292.
293.
294.
295.
Organs of Sense.
A Sectional View of the Skin, magnified 542
Upper Surface of the Tongue 548
The three kinds of PapiUse of the Tongue, magnified . . . Bowman. 548
Cartilages of the Nose Arnold 550
Bones and Cartilages of the Septum of the Nose ... do. 651
Nerves of Septum of Nose do, 553
A Vertical Section of the Eyeball, enlarged . . . • . • .554
The Choroid and Iris, enlarged Altered from Zinn 556
The Veins of the Choroid, enlarged Arnold 667
The Arteries of the Choroid and Iris, the Sclerotic has been ) , g^g
mostly removed, enlarged • )
The Arteria Centralis Retinae, Yellow Spot, &c., the anterior half of the
Eyeball being removed, enlarged 560
The Crystalline Lens, hardened and divided, enlarged . . Arnold 563
The Meibomian Glands, &c., seen from the Inner Surface of the ) , ^„^
Eyelids )
The Lachrymal Apparatus, right side 566
The Pinna, or Auricle, outer surface 568
The Muscles of the Pinna Arnold 569
A Front View of the Organ of Hearing, right side . . . Scarpa 670
View of Inner Wall of Tympanum, enlarged ....... 572
The Small Bones of the Ear, seen from the outside, enlarged . Arnold 674
The Osseous Labyrinth, laid open, enlarged .... Soemmering 677
The Cochlea laid open, enlarged ...... Arnold 578
The Membranous Labyrinth detached, enlarged . . . Breschet 580
LIST OF ILLUSTRATIONS.
Organs of Digestion and tlieir Appendages.
no. PAOE.
296. Sectional View of the Nose, Mouth, Pharynx, &c 583
297. The Permanent Teeth, external view . . 584
298. The Temporary, or Milk Teeth, external view 686
299. Vertical Section of a Molar Tooth 587
300. Vertical Section of a Bicuspid Tooth, magnified . . • . After Retzitis 587
301. to 306. Development of the Teeth Ooodsir 589
307. The Salivary Glands 593
308. The Eegions of the Abdomen and their contents, (edge of Costal Cartilages in
dotted Outline) 598
309. Diagram shewing the Reflections of the Peritoneum, as seen in \ Altered from
a Vertical Section of the Abdomen ) Quain
310. The Mucous Membrane of the Stomach and Duodenum, with the Bile Ducts 603
311. The Muscular Coat of the Stomach, (the innermost Layer is not seen) . . 604
312. Minute Anatomy of Mucous Membrane of Stomach . . . Dr. Sprott Boyd 605
313. Two Villi, magnified 608
314. Patch of Pleyer's Glands from the lower part of the Ileum .... 609
315. A portion of Peyer's Glands magnified Boehni 609
316. The Caecum and Colon laid open, to show the Ilio-csecal Valve .... 610
317. IVIinute structure of Large Intestine Boehvi 613
318. The Liver, upper surface 615
319. The Liver, under surface 616
320. Longitudinal section of an Hepatic Vein Kiernan. 618
321. Longitudinal section of a small Portal Vein and Canal . . do. 619
322. A transverse section of a small Portal Canal and its vessels . do. 619
323. The Pancreas and its relations 622
324. Transverse section of the Spleen, showing the Trabecular Tissue, the Splenic
Vein, and its branches ... 624
325. The Malpighian Corpuscles, and their relation with the Splenic Artery and its
branches 625
326. One of the Splenic Corpuscles, showing its relations with the blood-vessels . 626
327. Transverse section of the Human Spleen, showing the distribution of the
Splenic Artery and its branches 626
Organs of Circulation.
328. The right Auricle and Ventricle laid open, the anterior walls of both being
removed 630
329. The left Auricle and Ventricle laid open, the anterior walls of both being
removed ............. 634
330. Plan of the Foetal Circulation 638
Organs of Voice and Respiration.
331. Side view of Thyroid and Cricoid Cartilages 641
332. The Cartilages of the Larynx, posterior view 642
333. Interior of the Larynx, seen from above, enlarged .... Willis 645
33 i. Muscles of Larynx, side view, right ala of Thyroid Cartilage removed . 647
335. Front view of Cartilages of Larynx : the Trachea and Bronchi .... 649
336. Surgical anatomy of the Laryngo-tracheal Region 651
337. A transverse section of the Thorax, showing the relative position of the
Viscera, and the reflections of the Pleura3 652
338. Front view of the Heart and Lunsrs. 654
xxxii LIST OF ILLUSTRATIONS.
The Urinary and Generative Organs.
PIG. PAGE
339. Vertical sectioB of the Kidney 661
340. A Plan to shew the minute structure of the Kidney . . Bowman 661
341. Vertical section of Bladder, Penis, and Urethra . . . ■ . . . 665
342. The Bladder and Urethra laid open, seen from above 668
343. The Testis in situ, the Tunica Vaginalis having been laid open .... 677
344. Plan of a vertical section of the Testicle, to shew the arrangement of the
ducts 678
345. Base of the Bladder, with the Vasa Deferentia and Vesicula3 ) -r^ „ „^^
c, . T > Ealler 679
Semmales \
346. The Vulva, External Female Organs of Generation 682
347. Section of Female Pelvis, shewing Position of Viscera 684
348. The Uterus and its Appendages, anterior view .... Wilso7i 869
349. Inguinal Hernia, Superficial Dissection 693
350. Inguinal Hernia, showing the Internal Oblique, Cremaster, and Spermatic Canal 695
351. Inguinal Hernia, shewing the Transversalis Muscle, the Transversalis Fascia,
and the Internal Abdominal Ring 697
352. Femoral Hernia, Superficial Dissection 701
353. Femoral Hernia, shewing Fascia Lata and Saphenous Opening .... 702
354. Femoral Hernia, Iliac Portion of Fascia Lata removed, and Sheath of
Femoral Vessels and Femoral Canal exposed 704 ^
355. Hernia; the Eolations of the Femoral and Internal Abdominal Rings, seen
from within the Abdomen, right side 706
356. Variations in Origin and Course of Obturator Artery 706
357. Plan of Dissection of Perinaeum and Ischio-Rectal Region 710
358. The Perinseum ; the Integument and Superficial Layer of Superficial Fascia
reflected 712
359. The Superficial Muscles and Vessels of the Perinseum 713
360. Deep Perinseal Fascia ; on the Left Side the Anterior Layer has been removed 714
361. A View of the Position of the Viscera at the Outlet of the Pelvis . . . 717
362. A Transverse Section of the Pelvis, shewing the Pelvic Fascia . After Wilson 718
363. Side View of the Pelvic Viscera of the Male Subject, shewing the Pelvic and
Perinseal Fasciae 719
DESCRIPTIVE AND SURGICAL ANATOMY.
rjESCRIPTIVE ANATOMY comprises a detailed account of the numerous
organs of which the body is formed, especially with reference to their out-
ward form, their internal structure, the mutual relations they bear to each other,
and the successive conditions they present during their development.
Surgical Anatomy is, to the student of medicine and surgery, the most essential
branch of anatomical science, having reference more especially to an accurate know-
ledge of the more important regions, and consisting in the application of anatomy
generally to the practice of surgery.
The Study of Anatomy is commonly divided into several distinct branches,
according to the mutual resemblance of the organs; and these branches have cor-
responding denominations.
Osteology.
TN the construction of the human body, it would appear essential, in the first
place, to provide some dense and solid texture capable of giving support and
attachment to the softer parts of the frame, and at the same time to protect in
closed cavities the more important vital organs; and such a structure we find pro-
vided in the various bones, which form what is called the Skeleton.
Bone is one of the hardest structures of the animal body; it possesses also a cer-
tain degree of toughness and elasticity. Its colour, in a fresh state, is of a pinkish
white externally, and deep red within. Chemical analysis resolves bone into an
organic, or animal, and an inorganic, or earthy material, intimately combined
together; the animal matter giving to bone its elasticity and toughness, the earthy
part its hardness and solidity. The animal constituent may be separated from the
earthy, by steeping bone in a dilute solution of nitric or muriatic acid: by this
process the earthy constituents are gradually dissolved out, leaving a tough semi-
transparent substance which retains, in every respect, the original form of the
bone. This is often called cartilage, but differs from it in being softer, more flexible,
and, when boiled under a high pressure, it is almost entirely resolved into gelatine.
The earthy constituent may be obtained by subjecting a bone to strong heat in an
open fire with free access of air. By these means, the animal matter is entirely
consumed, the earthy part remaining as a white brittle substance still preserving
the original shape of the bone.
The organic or animal constituent of bone, forms about one-third, or 33*3 per
cent.; the inorganic or earthy matter, two-thirds, or 66*7 per cent.: as is seen in
the subjoined analysis by Bei'zelius: —
Animal Matter, Gelatine and Blood-vessels . 33*30
t Phosphate of Lime .
Inorganic \ Carbonate of Lime .
or < Fluoride of Calcium .
Earthy Matter, j Phosphate of Magnesia
i Soda and Chloride of Sodium
51-04
11-30
2-00
ri6
I'20
100-00
Adult
Old Age
20' 1 8 .
.. 12-2
74-84 .
.. 84-1
2 OSTEOLOGY.
The proportion between these two constituents varies at different periods of life,
as is seen in the following table from Schreger: —
Child
Animal matter . . 47"20
Earthy matter . . 48*48
There are facts of some practical interest, bearing upon the difference here
seen in the amount of the two constituents of bone, at different periods of life.
Thus, in the child, where the animal matter forms nearly one-half of the weight
of the bone, it is not uncommon to find, after an injury happening to the bones,
that they become bent, or only partially broken, from the large amount of flexible
animal matter which they contain. Again, also in aged people, where the bones
contain a large proportion of earthy matter, the animal matter at the same time
being deficient in quantity and quality, the bones are more brittle, their elasticity
is destroyed; and, hence, fracture take's place more readily. Some of the diseases,
also, to which bones are liable, mainly depend on the disproportion between the
two constituents of bone. Thus, in the disease called rickets, so common in the
children of scrofulous parents, the bones become bent and curved, either from
the superincumbent weight of the body, or under the action of certain muscles.
This depends upon some deficiency of the nutritive system, by which bone becomes
minus its normal proportion of earthy matter, whilst the animal matter is of un-
healthy quality. In the vertebra of a rickety subject. Dr. Bostock found in lOO
parts 79'75 animal, and 20*25 earthy matter.
The relative proportions of the two constituents of bone are found to differ in
different bones of the skeleton. Thus the p&trous portion of the temporal bone
contains a large proportion of earthy matter, the bones of the limbs contain more
earthy matter than those of the trunk, and those of the upper extremity, a larger
proportion than those of the lower.
On examining a section of any bone, it is seen to be composed of two kinds of
tissue, one of which is dense and compact in texture like ivory; the other open,
reticular, spongy, enclosing cancelli or spaces, and hence called spongy or cancel-
lated tissue. The compact tissue is always placed on the exterior of a bone; the
cancellous tissue is always internal. The relative quantity of these two kinds of
tissue varies in different bones, and in different parts of the same bone, as strength
or lightness is requisite.
Form of Bones. The various mechanical purposes for which bones are employed
in the animal economy require them to be of very different forms. All the scien-
tific principles of Architecture and Dynamics are more or less exemplified in the
construction of this part of the human body. The power of the arch in resisting
superincumbent pressure is well exhibited in various parts of the skeleton, such
as the human foot, and more especially in the vaulted roof of the cranium.
Bones are divisible into four classes : Long, Short, Flat, and Irregular.
The long bones are found chiefly in the limbs, where they form a system of
levers, which have to sustain the weight of the trunk, and to confer extensive
powers of locomotion. A long bone consists of a lengthened cylinder or shaft,
and two extremities. The shaft is a hollow cylinder, the walls consisting of dense
compact tissue of great thickness in the middle, and becoming thinner towards
the extremities; the spongy tissue is scanty, and the bone is hollowed out in its
interior to form the medullary canal. The extremities are generally somewhat
expanded for greater convenience of mutual connexion, and for the purposes of
articulation. Here the bone is made up of spongy tissue with only a thin coating
of compact substance. The long bones are the clavicle, humerus, radius, ulna,
femur, tibia, fibula, metacarpal, and metatarsal bones and the phalanges.
Short Bones. Where a part is intended for strength and compactness, and the
motion at the same time slight and limited, it is divided into a number of small
pieces united together by ligaments, and the separate bones are short and com-
pressed, such as the bones of the carpus and tarsus. These bones, in their struc-
GENERAL ANATOMY OF BONE. 3
ture, are spongy throughout, excepting at their surface, where there is a thin crust
of compact substance.
Flat Bones. Where the principal requirement is either extensive protection,
or tlie provision of broad surftices for muscular attachment, we find the osseous
structure remarkable for its slight thickness, becoming expanded into broad flat
plates, as is seen in the bones of the skull and shoulder-blade. These bones are
composed of two thin layers of compact tissue, enclosing a layer of cancellous
tissue of variable thickness. In the cranial bones, these layers of compact tissue
are familiarly known as the tables of the skull; the outer one is thick and tough,
the inner one thinner, denser, and more brittle, and hence termed the vitreous
table. The intervening cancellous tissue is called the diploe. The flat bones are
the occipital, parietal, frontal, nasal, lachrymal, vomer, scapulcB, and ossa inno-
minata.
The Irregular or Mixed bones are such as, from their peculiar form, cannot be
grouped under either of the preceding heads. Their structure is similar to that
of other bones, consisting of an external layer of compact, and of a spongy can-
cellous substance within. The irregular bones are the vertebrce, sacrum, coccyx,
temporal, sphenoid, ethmoid, superior maxillary, inferior maxillary, palate, infe-
rior turbinated, and hyoid.
Vessels of Bone. The blood-vessels of bone are very numerous. Those of the
compact tissue consist of a close and dense network of vessels, which ramify in a
fibrous membrane termed the periosteum, which covers the entire surface of the
bone in nearly every part. From this membrane, vessels pass thi-ough all parts of
the compact tissue, running through the canals which traverse its substance. The
cancellous tissue is supplied in a similar way, but by a less numerous set of
larger vessels, which, perforating the outer compact tissue, are distributed to the
cavities of the spongy portion of the bone. In the long bones, numerous apertures
may be seen at the ends near the articular surfaces, some of which give passage to
the arteries referred to; but the greater number, and these are the largest of them,
are for the veins of the cancellous tissue which run separately from the arteries.
The medullary canal is supplied by one large artery (or sometimes more), which
enters the bone at the nutritious foramen (situated, in most cases, near the centre
of the shaft), and perforates obliquely the compact substance. This vessel, usually
accompanied by one or two veins, sends branches upwards and downwards, to
supply the medullary membrane, which lines the central cavity and the adjoining
canals. The ramifications of this vessel anastomose with the arteries both of the
cancellous and compact tissues. The veins of bone are large, very numerous, and
run in tortuous canals in the cancellous texture, the sides of which are constructed
of a thin lamella of bone, perforated here and there for the passage of branches
from the adjacent cancelli. The veins thus enclosed and supported by the hard
structure, have exceedingly thin coats; and when the bony structure is divided,
they remain patulous, and do not contract in the canals in which they are con-
tained. Hence the constant occurrence of purulent absorption after amputation,
in those cases where the stump becomes inflamed, and the cancellous tissue is
infiltrated and bathed in pus. Lymphatic vessels have been traced into the sub-
stance of bone. Nerves, also, accompany the nutritious arteries into their interior.
Development of Bone. From the peculiar uses to which bone is applied, in
forming a hard skeleton or framework for the softer materials of the body, and in
enclosing and protecting some of the more important vital organs, we find its
development takes place at a very early period. Hence the parts that appear
soonest" in the embryo, are the vertebral column and the skull, the great central
column, to Avhich the other parts of the skeleton are appended. At an early period
of embryonic life, the parts destined to become bone consist of a congeries of cells,
Avhich constitutes the simplest form of cartilage. This temporary cartilage, as it
is termed, is an exact miniature of the bone which in due course is to take its
place; and as the process of ossification is slow, and not completed until adult life,
it increases in bulk by an interstitial development of new cells. The next step in
B 2
4 OSTEOLOGY.
this process is the ossification of the intercellular substance, and of the cells
composing the cartilage. Ossification commences in the interior of the cartilage
at certain points, called points or centres of ossification, from which it extends
into the surrounding substance. The period of ossification varies much in difierent
bones. It commences first in the clavicle, in which the primitive point appears
during the fifth week; next in the lower jaw. The ribs also, and the long bones
of the limbs, appear soon after. The number of ossific centres varies in diiferent
bones. In most of the short bones, it commences by a single point in the centre,
and proceeds towards the circumference. In the long bones, there is a central
point of ossification for the shaft or diaphysis; and one for each extremity, the
epiphyses. That for the shaft is the first to appear; those for the extremities
appear later. For a long period after birth, a thin layer of unossified cartilage
remains between the diaphysis and epiphyses, until their growth is finally com-
pleted. Processes such as the trochanters that have separate centres of ossifi-
cation, are called epiphyses previous to their union.
Growth of Bone. Increase in the length of a bone, is provided for by the
development of new bone from either end of the shaft (diaphysis); and in the
thickness, by the deposition of new matter upon the surfece : but when growth
is at an end, the epiphyses become solidly united to the ends of the diaphysis,
and the bone is completely formed. A knowledge of the exact periods when the
epiphyses become joined to the shaft, aids the surgeon in the diagnosis of many of
the injuries to which the joints are liable; for it not unfrequently happens, that
on the application of severe force to a joint, the epiphyses become separated from
the shaft, and such injuries may be mistaken for fracture.
The order in which the epiphyses become ttnited to the shaft, follows a pecu-
liar law, which appears to be regulated by the direction of the nutritious artery
of the bone. Thus the arteries of the bones of the arm and forearm converge
towards the elbow, and the epiphyses of the bones forming this joint become
united to the shaft before those at the opposite extremity. In the lower extre-
mities, on the contrary, the nutritious arteries pass in a direction from the knee;
that is, upwards in the femur, downwards in the tibia and fibula; and in them it
is observed, that the upper epiphysis of the femur, and the lower epiphyses of the
tibia and fibula, become first united to the shaft.
A diseased condition of any joint makes considerable variation in the peAod
of development of the several bones which enter into its formation. Thus, in
chronic inflammation occurring in a joint at an early period of life, the epiphysal
cartilages take on premature ossification; this process proceeding so rapidly, that
it speedily becomes converted into bone, which becomes united to the shaft, and
the bone ever after is considerably diminished in length: hence partial atrophy of
the limb is the result.
The entire skeleton in an adult, consists of 2o6 distinct bones. These are —
Cranium . . . , . .
Ossicula auditus .....
Face .......
Vertebral column (sacrum and coccyx included)
Os hyoides, sternum, and ribs .
Upper extremities .....
Lower extremities .....
26
26
64
62
206
In this enumeration, the sesamoid and Wormian bones are excluded, as also
are the teeth, which difier from bone both in structure, development, and mode of
growth. The skeleton consists of a central column or Spine; of three great cavi-
ties, the Skull, Thorax, and Pelvis; and of the Superior and Inferior Extremities.
GENERAL CHARACTERS OF THE VERTEBRA. 5
THE SPINE.
The Spine is a flexuous column, formed of a series of bones called VertehrcB.
The Vertebras are divided into true ?in^ false.
The true vertebrae are twenty-four in number, and have received the names
cervical, dorsal, and lumbar, according to the position which they occupy;
seven being found in the cervical region, twelve in the dorsal, and five in the
lumbar.
The false vertebrae, nine in number, are firmly united, so as to form two bones
— five entering into the formation of the upper bone or sacrum, and four into
the terminal bone of the spine or coccyx.
!7 Cei'vical.
12 Dorsal.
5 Lumbar.
False VertebrcB, Q \ ^ r-^
^ ( 4 Coccyx.
General Characters of the Vertebra.
Each vertebi'a consists of two parts, an anterior solid segment or body, forming
the chief pillar of supj)ort; a posterior segment, the arch, forming part of a hollow
cylinder for protection. The arch is formed of two pedicles and two laminae,
supporting seven processes; viz. four articular, two transverse, and one spinous
process.
The Body is the largest and most solid part of a vertebra, serving to support
the weight of the cranium and trunk. Above and below it is slightly concave,
presenting a rim around its circumference; and its surfaces are rough, for the
attachment of the intervertebral fibro-cartilages. In front it is convex from side
to side, concave from above downwards. Behind, flat from above downwards, and
slightly concave from side to side. Its anterior surface is perforated by a few
small apertures, for the passage of nutrient vessels; whilst on the posterior surface
is a single irregular- shaped, or occasionally several large apertures, for the exit of
veins from the body of the vertebra, the vencB basis vertebrcB.
The Pedicles project backwards, one on each side, from the upper part of the
body of the vertebrte, at the line of junction of its posterior and lateral surfaces;
they form the lateral parts of the arch, which is completed posteriorly by the two
laminae. The concavities above and below the pedicles are the intervertebral
notches; they are four in number, two on each side, the inferior ones being
always the deeper.
The Lamiiice consist of two broad plates of bone, Avhich complete the vertebral
arch behind, enclosing a foramen which serves for the protection of the spinal
cord; they are connected to the body through the intervention of the pedicles.
Their upper and lower borders are rough, for the attachment of the ligamenta
subfiava.
The Spinous Process projects backwards from the junction of the two laminae,
and serves for the attachment of muscles.
The Transverse Processes, two in number, project one at each side from the
point where the articular processes join the pedicle. They also serve for the
attachment of muscles.
The Articular Processes are four in number; two superior, the smooth surfaces
of which are directed more or less backwards; and two inferior, the articular
surfaces of which look more or less forwards.
Characters of the Cervical Vertebrae (fig. i).
The Body is smaller than in any other region of the spine, thicker before than
behind, and broader from side to side than from before backwards. Its upper
surface is concave transversely, and presents a projecting lip on each side; its lower
OSTEOLOGY.
surface being convex from side to side, concave from before backwards, and present-
ing laterally a shallow concavity, which receives the corresponding projecting
lip of the adjacent vertebra. The pedicles are directed obliquely outwards, and
the superior intervertebral notches are slightly deeper, but narrower, than the
inferior. The lamina are narrow, long, thinner above than below, and imbricated
i.e. overlapping each other; enclosing the foramen, which is very large, and of a
triangular form. The spinous processes are short, bifid at the extremity, the two
divisions being often of unequal size. They increase in length from the fourth
to the seventh. The transverse processes are short, directed downwards, outwards
and forwards, bifid at their extremity, and marked by a groove along their upper
surface, which runs downwards and outwards from the superior intervertebral
notch, and serves for the transmission of one of the cervical nerves. The trans-
verse processes are pierced at their base by a foramen, for the transmission of
the vertebral artery, vein, and plexus of nerves. Each of these processes is formed
by two roots : the anterior or smaller, which is attached to the side of the body
corresponds to the ribs in the dorsal region ; the posterior is larger, springs from
the pedicle, and corresponds to the true transverse processes. It is by the junc-
tion of these two processes, that the vertebral foi'amen is formed. The extremities
of each of these roots form the anterior and posterior tubercles of the transverse
I. — A Cervical Vertebra.
Anterior TnhnTcle of Trans.Proc
For a men far Yorbebr.al Art 1.
PostenorTuicrcle of Trans . P roc-
ansversc ±^roc£ss.
,-Siipe.rior Artilcular ProcessK
-Inferior AatLculiiT Process
processes. The articular processes are oblique: the superior are of an oval form,
flattened, and directed upwards and backwards; the inferior downwards and
forwards.
The peculiar vertebriB in the cervical region are the first or Atlas; the second
or Axis; and the seventh or Vertebra prominens.
The Atlas (fig. 2) (so named from supporting the globe of the head). The chief
2. — 1st Cervical Vertebra, or Atlas.
Tuhercle
Tro/iis. Proct
■Foratne/i £o\
Vertebral/ ArA
Qrooifefcr VerD^i^ A rt -f
ajid If.^ Gerv.N'e'rvs
Spin, Proc,
CERVICAL VERTEBRiE.
peculiarities of this bone are, that it has neither body, spinous process, nor pedicles.
It consists of an anterior arch, a posterior arch, and two lateral masses. The
anterior or lesser arch, which forms about one-fifth of the bone, represents the
front part of the body of a vertebra; its anterior surface is convex, and presents
about its centre a tubercle for the attachment of the Longus colli muscle; posteriorly
it is concave, and marked by a smooth oval surface, for articulation with the odontoid
process of the axis. The posterior or greater arch, which forms about two-fifths
of the circumference of the bone, terminates behind in a tubercle, which is the ru-
diment of a spinous process, and gives origin to the Rectus capitis posticus minor.
The posterior part of the arch presents above a rounded edge; whilst in front,
immediately behind the superior articular processes, are two grooves, sometimes
converted into foramina by delicate bony spiculse. These grooves represent the
superior intervertebral notches, and are peculiar from being situated behind the
articular processes, instead of before them, as in the other vertebrse. They serve
for the transmission of the vertebral artery, which, ascending through the foramen
in the transverse process, winds around the lateral mass in a direction backwards
and inwards. They also transmit the sub-occipital nerves. On the under surface
of the posterior arch, in the same situation, are two other grooves, placed behind
the lateral masses, and representing the inferior intervertebral notches of other
vertebrge. They are much less marked than the superior. The lateral masses,
which are the most bulky and solid parts of the Atlas, present two articulating pro-
cesses above, and two below. The two superior are of large size, oval, concave,
and approach towards one another in front, but diverge behind; they are directed
upwards, inwards, and a little backwards, forming a kind of cup for the condyles
of the occipital bone, and are admirably adapted to the nodding movements of the
head; whilst the inferior, which are circular in form, and flattened, are directed
downwards, inwards, and a little backwards, articulating with the axis, and per-
mitting the rotatory movements. Just below the inner margin of each superior
articular surface, is a small tubercle, for the attachment of a ligament which,
stretching across the ring of the Atlas, divides it into two unequal parts ; the anterior
or smaller segment receiving the odontoid process of the Axis, the posterior allowing
the transmission of the spinal cord and its membranes. This ligament and the
odontoid process are marked in the figure in dotted outline. The transverse pro-
cesses are of large size, long, not bifid, perforated at their base by a canal for the
vertebral artery, which is directed from below, upwards and backwards.
The Axis (fig. 3) (so named from forming the pivot upon which the head
3. — 2nd Cervical Vertebra, or Axis.
Odontoid Pi'oc ,
R
Artec
'Spin. troc.J
Artie. iSurf. for Atlas
B odh
Trans .f roe.
Infer. A rtic.Proc.
rotates). The most distinctive character of this bone is the existence of a strong
prominent process, tooth-like in form (hence the name odontoid), which arises per-
pendicularly from the upper part of the body. The body is of a triangular form;
OSTEOLOGY.
its anterior surface deeper than the posterior, presents a median longitudinal ridge,
separating two lateral depressed surfaces for the attachment of the Longi colli
muscles. The odontoid process presents two oval articulating surfaces: one in
front, for articulation with the Atlas; another behind, for the transverse ligament;
the apex is pointed, and on either side of it is seen a rough impression for the
attachment of the odontoid or chefek ligaments; whilst the base, where attached to
the body, is constricted, so as to prevent displacement from the transverse ligament,
which binds it in this situation to the anterior arch of the Atlas. On each side
of this process are seen the superior articular surfaces; they are round, convex,
directed upwards and outwards, and are peculiar in being supported on the body,
pedicles, and transverse processes. The inferior articular surfaces, which are pos-
terior and external to these, have the same direction as those of the other cervical
vertebrae. The superior intervertebral notches are very shallow, and lie behind the
articular processes; the inferior in front of them, as in the other cervical vertebrae.
The transverse processes are very small, not bifid, and perforated by the vertebral
foramen, which is directed obliquely upwards, and outwards. The laminae are
thick and strong, and the spinous process is of large size, very strong, deeply chan-
nelled on its under surface, and presenting a bifid tubercular extremity for the
attachment of muscles.
Seventh Cervical. The most distinctive character of this vertebra is the existence
of a very large, long, and prominent spinous process; hence the name ' Vertebra pro-
minens.' This process is thick, nearly horizontal in direction, not bifurcated,
and has attached to it the ligamentum nuchae. The foramina in the transverse
processes are small, often wanting, and when present do not give passage to
the vertebral artery; their upper surface presents only a slight groove, and gene-
rally only a trace of bifurcation at their extremity.
Characters of the Dorsal Vertebra.
The Dorsal Vertebrce (fig. 4) are intermediate in size between the cervical and
lumbar. The body is somewhat triangular in form, broader in the antero-posterior than
/Stujacrior ^I'tie. JBrocess^
4. — A Dorsal Vertebra.
I.
Devii. facet for head ofRil
Facet fir Tubercle ofRiJ)
i
Dem iCacet for head of Rib
Infer. Artie .Ftoc.
in the lateral direction, more particularly in the middle of the dorsal region, thicker
behind than in front, flat above and below, deeply concave behind, and marked on
each lateral surface, near the root of the pedicle, by two demi-facets, one above,
the other below. These are covered with cartilage in the recent state; and, when
DORSAL VERTEBRA.
articulated with the adjoining vertebrse, form oval surfaces for the reception of
the heads of the corresponding ribs. The pedicles are strong, and the inferior
intervertebral notches of large size. The lamina3 are broad and thick, and the spinal
foramen small, and of a round or slightly oval form. The articular surfaces are
flat, the superior being directed backwards and a little outwards and upwards, the
infei'ior forwards and a little inwards and downwards. The transverse processes
are thick, strong, and of great length, directed obliquely backwards and outwards,
presenting a clubbed extremity, lipped on its anterior part by a small concave
surface, for articulation with the tubercle of a rib. The spinous processes are
long, directed obliquely downwards, and terminated by a tubercle.
The peculiar dorsal vertebrse are the first, ninth, tenth, eleventh, and twelfth
(%-5)'
5. — Peculiar Dorsal Vertebrae.
'A^n entire facet aioi/e
ADemifaeet ielow-
'■iJif—AJJ emi-faeet alove
Oive entire fa,eei
An entire facet
5-'^*i3il \N'> facet onTrans.Proo.
which is Tti.di'me7ita/ry
An entirefacet
No facet onFrans. 211^
Infer. Artie. Proe
aon vex aTid turned
outward
The First Dorsal Vertebra may be distinguished by the existence on each side
of the body, of a single entire articular facet for the head of the first rib, and a
10
OSTEOLOGY.
half facet for the upper half of the second. The upper surface of the body is like
that of a cervical vertebra, being broad transversely, concave, and lipped on each
side. The superior articular surfaces are oblique, and the spinous process thick,
long, and almost horizontal.
The Ninth Dorsal has no demi-facet below.
The Tenth Dorsal has an entire articular facet at each side above; no demi-
facet below.
In the Eleventh Dorsal, the body approaches in its form to the lumbar; and
has a single entire articular surface on each side. The transverse processes are
very short, and have no articular surfaces at their extremities.
The Tioelfth Dorsal has the same characters as the eleventh; but may be
distinguished from it by the transverse processes being quite rudimentary, and the
inferior articular surfaces being convex and turned outwards, like those of the
lumbar vertebrae.
The smallest dorsal vertebra is the fourth. The vertebrae increase in size from
that point downwards to the twelfth, and upwards to the first. The spinous
processes also, from the eighth downwards, become shorter, and are directed more
horizontally.
Characters of the Lumbar Vertebra.
The Lumbar Vertebras (fig. 6) are the largest segments of the vertebral column.
The Body is large, broad from side to side, flat above, and below, and thicker
6. — A Lumbar Vertebra.
before than behind. The pedicles are very strong, directed backwards; and the
inferior intervertebral notches are of large size. The laminae are short, but broad
and strong; and the foramen triangular, larger than in the dorsal, smaller than in
the cervical region. The superior articular processes are concave, and directed
backwards and inwards; the inferior, convex, and directed forwards and outwards.
Projecting backwards from each of the superior articular processes is a tubercle,
the representative of the transverse processes in the dorsal and cervical regions.
The transverse processes are long, slender, directed a little backwards, and present,
at the posterior part of their base, a small tubercle, which is directed downwards.
The spinous processes are thick and broad, somewhat quadrilateral, horizontal in
direction, and thicker below than above.
The Fifth Lumbar vertebra is peculiar from having the body much thicker in
front than behind, which accounts for the prominence of the sacro-vertebral
articulation.
Structure of the Vertebrce. The structure of a vertebra differs in different parts.
The Body is composed almost entirely of light spongy cancellous tissue, having a
thin coating of compact tissue on its external surface, permeated throughout its
interior with large canals for the reception of veins, which converge towards a
DEVELOPMENT OF THE VERTEBRAE.
II
single large irregular or several small apertures at the posterior part of the body
of each bone. The arch and processes projecting from it have, on the contrary,
an exceedingly thick covering of compact tissue.
Development. Each vertebra
7. — Development of a Vertebra.
Sif S jyvimary eeyitres
is formed of three primary cen-
tres of ossification (fig. 7), one
for each lamella and its pro-
cesses, and one for the body.
Those for the lamellae appear
about the sixth week of foetal
life, in the situation where the
transverse processes afterwards
project, the ossific granules
shooting backwards to the spine,
forwards to the body, and out-
wards into the transverse and
articular processes. That for
the body makes its appearance
in the middle of the cartilage
about the eighth week. At
birth, these three pieces are
perfectly separate. During the
first year, the lateral portions
become partly united behind,
in the situation of the spinous
process, and thus the arch is
formed. About the third year,
the body is joined to the arch
on each side, in such a manner,
that the body is formed from
the three original centres of
ossification. Before puberty,
no other changes occur, ex-
cepting a gradual increase of
growth of these primary cen-
tres, the upper and under sur-
face of the bodies, and the ends
of the transverse and spinous
processes, being tipped with
cartilage, in which ossific gra-
nules are not as yet deposited.
At sixteen years (fig. 8), four
secondary centres appear, one
for the tip of each transverse
process, and two (sometimes
united into one) for the spinous
process. At twenty-one years
(fig. 9), two thin circular
plates of bone are formed, one
for the upper, and one for the
under surface of the body. All
these become joined, and the
bone is completely formed
about the thirtieth year of life.
Exceptions to this mode of
development occur in the first,
second,and seventh cervical, and
in those of the lumbar region.
/JurBody (8'?.> iinck)
f for each XavieUa (6 -■ week 1
fy J4., Secondary Centre^'
f/ ■foT eaeJi,
TrcLJus.Proo.
(iSy v.]
9-
lates
1 for upver surfaci\
of lady L
Irs
\—ifor u?i({<}r stivfacA
f
bod'
y
o
I o. — Axis.
£1/ 3 eeiitres
f ,fvr aritej'. aiv& f'^^y ■'']
\ f for each ), , ,.^,
^•^j''_, I \befo-ro birth
IcjteraL mam) •'
II. — Axis.
S centTes
Z for odo7iti>£d proa fetf-oioj
/for each Zcbteral jno,ts
' /for tody (6'^ mo.)
12. — Lumbar Vertebra.
^ axtdituynal ccjitrea
for tvherel^s on Su.p. Artie. Proo.
12 OSTEOLOGY.
The Atlas (fig. lo) is developed by three centres. One (sometimes two) for
the anterior arch, and one for each lateral mass. The ossific centres for each
lateral mass commence before birth. At birth, the anterior arch is altogether
cartilaginous, and the two lateral pieces are separated from one another behind.
The nucleus for the anterior arch appears in the first year, between the second and
third years the two lateral pieces unite, and join the anterior part at the age of
five or six years. There is frequently a separate epiphysis for the rudimentary
spine.
The Axis (fig. ii) is developed hj five centres; three for its anterior part, and
two for the posterior. The three anterior centres are, one for the lower part of
the body, and two for the odontoid process and upper part of the body; the two
posterior ones are, one for each lamella. At about the sixth month of foetal life,
those for the body and odontoid process make their appearance, the two for the
odontoid process joining before birth. At birth the bone consists of four pieces,
two anterior and two lateral. At the fourth year the body and odontoid process are
completely joined.
The Seventh Cervical. The anterior or costal part of the transverse process
of the seventh cervical, is developed from a separate osseous centre at about the
sixth month of foetal life, and joins the body and posterior division of the trans-
verse process between the fifth and sixth years. Sometimes this process continues
as a separate piece, and becoming lengthened outwards, constitutes what is known
as a cervical rib.
The Lumbar VertebrcB (fig. 12) have two additional centres (besides those
peculiar to the vertebrae generally), for the tubercles, which project from the back
part of the superior articular processes. The transverse process of the first lumbar
is sometimes developed as a separate piece, which may remain permanently uncon-
nected with the remaining portion of the bone; thus forming a lumbar rib, a pecu-
liarity which is sometimes, though rarely, met with.
Progress of Ossification in the Spine generally. Ossification of the laminae
of the vertebrae commences at the upper part of the spine, and proceeds gradually
downwards; hence the frequent occurrence of spina bifida in the lower part of the
spinal column. Ossification of the bodies, on the other hand, commences a little
below the centre of the spinal column, and extends both upwards and downwards.
Although, however, the ossific nuclei make their first appearance in the lower
dorsal vertebrae (about the ninth), the lumbar and first sacral are those in which
these nuclei are largest at birth.
The False Vertebra.
The False Vertebree consist of nine pieces, which are united so as to form two
bones, five entering into the formation of the sacrum, four the coccyx.
The Sacrum (fig. 13) is a large triangular bone, situated at the lower part
of the vertebral column, and at the upper and back part of the pelvic cavity,
where it is inserted like a wedge between the two ossa innominata; its upper
part, or base, articulating with the last lumbar vertebra, its apex with the coccyx.
The sacrum is curved upon itself, and placed very obliquely, its upper extremity
projecting forwards, forming, with the last lumbar vertebra, a very prominent
angle, called the promontory or sacro-vertebral angle, whilst its central part is
directed backwards, so as to give increased capacity to the pelvic cavity. It pre-
sents for examination an anterior and posterior surface, two lateral surfaces, a base,
an apex, and a central canal.
The Anterior Surface is deeply concave from above downwards, and slightly
so from side to side. In the middle are seen four transverse lines, indicating the
original division of the bone into five separate pieces. The portions of bone inter-
vening between the lines correspond to the bodies of the vertebra?; they are slightly
concave longitudinally, and diminish in size from above downwards. At the ex-
tremities of each of these lines, are seen the anterior sacral foramina, analogous
to the intervertebral foramina, four in number on each side, somewhat I'ounded in
I
SACRUM.
13
form, diminishing in size from above downwards, and directed outwards and for-
wards; tliey transmit the anterior branches of tlie sacral nerves. External to
these foramina, is the lateral mass, formed by the coalesced transverse processes
13. — Saciiim, Anterior Surface.
FTonwnioru
of the sacral vertebrae, traversed by four broad shallow grooves, which lodge the
anterior sacral nerves as they pass outwards, the grooves being separated by pro-
minent ridges of bone, which give attachment to the slips of the Pyriformis
muscle.
The Posterior Surface (fig. 14) is convex, and much narrower than the ante-
rior. In the middle line, are three or four tubercles, sometimes connected
together, which represent the rudimentary spinous processes. Of these tubercles,
the first is usually very prominent, and perfectly separate from the rest; the
second, third, and fourth, existing either separate, or united into a ridge, which
diminishes in size as it descends; the fifth, and sometimes the fourth, remaining
undeveloped, and exposing below, the lower end of the sacral canal. External to
the spinous processes on each side, are the lamincB, broad and well marked in the
three first pieces; the lower part of the fourth, and the whole of the fifth, being
undeveloped: in this situation the sacral canal is exposed. External to the laminae
are a linear series of indistinct tubercles representing the articular processes; the
upper pair are well developed; the second and third are small; the fourth and fifth
(usually blended together) are situated on each side of the sacral canal: they are
called the sacral cornua, and articulate with the cornua of the coccyx. External
to the articular processes are the four posterior sacral foramina; they are smaller in
size, and less regular in form than the anterior, and- transmit the posterior branches
of the sacral nerves. On the outer side of the posterior sacral foramina are a
series of tubercles, representing the rudimentary transverse processes. The first
pair of transverse tubercles are very distinct, and correspond with each superior
H
OSTEOLOGY.
angle of the bone; the second, small in size, enter into the formation of the sacro-
iliac articulation; the third give attachment to the oblique sacro-iliac ligaments;
14. — Sacrum Posterior Surface.
Inner X cf £M
l^u 't. sacral for.
and the fourth and fifth to the great sacro-ischiatic ligaments. The interspace
between the spinous and transverse processes of the sacrum, presents a wide shal-
low concavity, called the sacral groove; it is continuous above with the vertebral
groove, and lodges the origin of the Erector Spina3.
The Lateral Surface, broad above, becomes narrowed into a thin edge below.
Its upper half presents in front a broad ear-shaped surface for articulation with
the ilium. This is called the auricular or ear-shaped surface, and in the fresh
state is coated with cartilage. It is bounded posteriorly by deep and rough impres-
sions, for the attachment of the sacro-iliac ligaments. The lower half is thin and
sharp, and gives attachment to the greater and lesser sacro-ischiatic ligaments;
below, it presents a deep notch, which is converted into a foramen by articulation
with the transverse process of the upper piece " of the coccyx, and transmits the
anterior branch of the fifth sacral nerve.
The Base of the sacrum, which is broad and expanded, is directed upwards and
forwards. In the middle is seen an oval articular surface, which corresponds with
the under-surface of the body of the last lumbar vertebra, bounded behind by
the large triangular orifice of the sacral canal. This orifice is formed behind by
the spinous process and laminse of the first sacral vertebra, whilst projecting from
it on each side are the superior articular processes; they are oval, concave,
directed backwards and inwards, like the superior articular processes of a lumbar
vertebra^ in front of each articular process ik an intervertebral notch, which
forms the lower half of the last intervertebral foramen. Lastly, on each side of
the articular surface is a broad and flat triangular surface of bone, called the al<s
DEVELOPMENT OF SACRUM.
15
of the sacrum; they extend outwards, and are continuous on each side with the
iliac fossee.
The Apex, directed downwards and forwards, presents a small oval concave
surface for articulation with the coccyx.
The Sacral Canal runs throughout the greater part of the bone; it is large
and triangular in form above, small and flattened from before backwards below.
In this situation, its posterior wall is incomplete, from the non-development of
the lamina and spinous processes. It lodges the sacral nerves, and is perforated
by the anterior and posterior sacral foramina, through which these pass out.
Structure. It consists of much loose spongy tissue within, invested externally
by a thin layer of compact tissue.
Differences in the Sacrum of the Male and Female. The sacrum in the
female is usually wider than in the male, and it is much less curved, the upper half
of the bone being nearly straight, the lower half presenting the greatest amount
of curvature. The bone is also directed more obliquely backwards; which increases
the size of the pelvic cavity, and forms a more prominent sacro-vertebral angle.
In the male the curvature is more evenly distributed over the whole length of the
bone, and is altogether greater than in the female.
Peculiarities of the Sacrum. This bone, in some cases, consists of six instead
of five pieces; occasionally the number is reduced to four. Sometimes the bodies
of the first and second vertebrge are not joined, or the laminas and spinous processes
have not coalesced with the rest of the bone. Occasionally the superior transverse
tubercles are not joined to the rest of the bone on one or both sides; and, lastly,
the sacral canal may be open for nearly the lower half of the bone, in consequence
of the imperfect development of the laminas and spinous processes. The sacrum also
varies considerably with respect to its degree of curvature. From the examination
of a large number of skeletons, it
would appear, that, in one set of cases,
the anterior surface of this bone was
nearly straight, the curvature, which
was very slight, affecting only its lower
end. In another set of cases, the bone
was curved throughout its whole length,
but especially towards its middle. In
a third set, the degree of curvature was
less marked, and aifected especially the
lower third of the bone.
Development of Sacrum (fig. 15).
The sacrum, formed by the union of
five vertebrae, has thirty-Jive centres
of ossification. Each of the three first
pieces is developed by seven centres;
viz., three for the body, one for its cen-
tral part, one for each epiphysal lamella
on its upper and under surface, and one
for each of the laminas: so far the first
three sacral vertebrse, as well as the
two last, are developed like the other
pieces of the vertebral column. One
of the characteristic points in the deve-
lopment of this bone, consists in the
existence of two additional centres for
each of the first three pieces, which
appear one on each side, close to the
anterior sacral foramina, and correspond
to the transverse processes of the lum-
bar vertebrae.
— Development of Sacrum.
FoTTneA hv ivnion of 6 V&rteorcE.
2 cJietraeterkstiyC points.
1 £?
a AAiitioTicbl ce/ritres
the first 3 ipieces *
burt./i
a JLjifphiisayL
for each laterctl surTa.ce
LcLmcnce
rfct
at 25 "
i6
OSTEOLOGY.
Each of the two last pieces is developed by five centres: three for the body; viz.,
one for its central part, and one for each of the epiphy sal lamellas ; and one for each
of the laminae.
A second characteristic point in the development of this bone consists in each
lateral surface of the sacrum being developed by two epiphysal points, one for the
auricular surface, and one for the thin lateral border of the bone.
Period of Development. At about the eighth or ninth week of foetal life, ossifi-
cation of the central part of the bodies of the three first vertebrae commences, and,
at a somewhat later period, that of the two last. Between the sixth and eighth
months, ossification of the lamellte takes place; and at about the same period the
characteristic osseous tubercles for the three first sacral vertebrse make their appear-
ance. The lateral pieces join to form the arch, and are united to the bodies, first,
in the lowest vertebrae. This occurs about the second year, the uppermost seg-
ment appearing as a single piece about the fifth or sixth year. About the six-
teenth year the epiphysal lamellae for the bodies are formed; and between the
eighteenth and twentieth years those for each lateral surface of the sacrum make
their appearance. At about this period, the two last segments are joined to one
another; and this process gradually extending upwards, all the pieces become united,
and the bone completely formed from the twenty-fifth to the thirtieth year of life.
Articulations. With four bones; the last lumbar vertebra, coccyx, and the two
ossa innominata.
Attacliment of Muscles. The Pyriformis and Coccygeus on either side, behind
the Gluteus maximus and Erector Spinae.
The Coccyjj;.
The Coccyx {kokkv^, cuckoo), so called from resembling a cuckoo's beak,
(fig. 1 6) is formed of four small segments of bone, the most rudimentary parts of
the vertebral column. Of these, the first is the largest, and often exists as a
separate piece, the three last diminishing in size from
above downwards, are blended together so as to form
a single bone. The gradual diminution in the size of
the pieces gives this bone a triangular form, articula-
ting by its base with the apex of the sacrum. It
Ti-a/if. presents for examination an anterior and posterior
^''""^ surface, two borders, a base, and an apex. The an-
terior surface is slightly concave, and marked with
three transverse grooves, indicating the points of junc-
tion of the diiferent pieces. It has attached to it the
anterior sacro-coccygeal ligament and levator ani mus-
cle, and supports the lower end of the rectum.
The posterior surface is convex, marked by grooves
similar to those on the anterior surface, and presents
on each side a linear row of tubercles, which repre-
sent the articular processes of the coccygeal vertebrae.
Of these, the superior pair are very large; they are
called the cornua of the coccyx, and projecting up-
wards, articulate with the cornua of the sacrum, the
junction between these two bones completing the
fifth sacral foramen for the transmission of the poste-
rior branch of the fifth sacral nerve. The lateral
borders are thin, and present a series of small emi-
nences, which represent the transverse processes of
the coccygeal vertebrae. Of these, the first on each
side is of large size, flattened from before backwards,
and often ascends upwards to join the lower part of
the thin lateral edge of the sacrum, thus completing
the fifth sacral foramen: the others diminish in size
1 6. — Coccyx.
COCCYX
Cornua,
Rudirrv,
jd-Tzterior jS%CT'faee
rfoiCB
THE SPINE.
17
17. — Lateral View of Spine.
IV Dorsal
fSr-
I'J'J ,
1^." Lumbar ~
4-1
I
from above downwards, and are often wanting.
The borders of the coccyx are narrow, and
give attachment on each side to the sacro-
sciatic ligaments and Coccygeus muscle. The
base presents an oval surface for articulation
with the sacrum. The apex is rounded, and
has attached to it the tendon of the external
Sphincter ani muscle. It is occasionally bifid,
and sometimes deflected to one or other side.
Development. The coccyx is developed by
four centres, one for each piece. Occasionally
one of the three first pieces of this bone is de-
veloped by two centres, placed side by side.
The periods when the ossific nuclei make their
appearance is the following: in the first seg-
ment, at birth; in the second piece, at from
five to ten years; in the third, from ten to
fifteen years; in the fourth, from fifteen to
twenty years. As age advances, these various
segments become united in the following order:
the two first pieces join, then the third and
fourth; and, lastly the bone is completed by
the union of the second and third. At a late
period of life, especially in females, the coccyx
becomes joined to the end of the sacrum.
Articulation. With the sacrum.
Attachment of Muscles. On either side, the
Coccygeus; behind, the Gluteus maximus; at
its apex, the Sphincter ani; and in front,
the Levator ani.
Of the Spine in general. — The spinal
column, formed by the junction of the verte-
brae, is situated in the median line, at the pos-
terior part of the trunk: its average length is
about two feet two or three inches; the lum-
bar region contributing seven parts, the dor-
sal eleven, and the cervical five.
Viewed in front, it presents two pyramids
joined together at their bases, the upper one
being formed by all the true vertebrae from the
second cervical to the last lumbar; the lower
one by the false vertebras, the sacrum, and
coccyx. Viewed somewhat more closely, the
uppermost pyramid is seen to be formed of
three smaller pyramids. Of these the most
superior one consists of the six lower cervical
vertebras, its apex being formed by the axis or
second cervical, its base by the first dorsal.
The second pyramid, which is inverted, is
formed by the four upper dorsal vertebrae, the
base being at the first dorsal, the smaller end
at the fourth. The third pyramid commences
at the fourth dorsal, and gradually increases
in size to the fifth lumbar.
Viewed laterally (fig. 1 7), the spinal column
presents several curves. In the dorsal region,
the seat of the principal curvature, the spine
c
1 8 OSTEOLOGY.
is concave anteriorly; whilst in the cervical and lumbar regions it is convex an-
teriorly, especially in the latter. The spine has also a slight lateral curvature,
the convexity of which is directed towards the right side. This is most probably
produced, as Bichat first explained, from the effect of muscular action; most persons
using the right arm in preference to the left, especially in making long-continued
efforts, when the body is curved to the right side. In support of this explanation,
it has been found by Beclard, that in one or two individuals who were left-handed,
the lateral curvature was directed to the left side.
The spinal column presents for examination an anterior, a posterior, and two
lateral surfaces, a base, summit, and vertebral canal.
The anterior surface presents the bodies of the vertebrae separated in the fresh
state by the intervertebral discs. The bodies are broad in the cervical region,
narrow in the upper part of the dorsal, and broadest in the lumbar region. The
whole of this surface is convex transyersely, concave from above downwards in
the dorsal region, and convex in the same direction in the cervical and lumbar
regions.
The posterior surface presents in the median line the spinous processes. These
are short, horizontal, with bifid extremities in the cervical region. In the dorsal
region, they are directed obliquely above, assume almost a vertical direction in the
middle, and are horizontal, like the spines of the lumbar vertebrce, below. They
are separated by considerable intervals in the loins, by narrower intervals in the
neck, and are closely approximated in the middle of the dorsal region. On either
side of the spinous processes; extending the whole length of the column, is the
vertebral groove, formed by the laminae in the cervical and lumbar regions, where
it is shallow, and by the laminae and transverse processes in the dorsal region,
where it is deep and broad. In the recent state, these grooves lodge the deep
muscles of the back. External to the vertebral grooves are the articular processes,
and still more externally the transverse processes. In the dorsal region, these
latter processes stand backwards, on a place considerably posterior to the same pro-
cesses in the cervical and lumbar regions. The transverse processes in certain
regions of the spine are formed of two different parts, or segments. In the cer-
vical region, these two segments are distinct; the one arising from the side of the
body, the other from the pedicle of the vertebra; and these uniting, enclose the
vertebral foramen. In the dorsal region, the anterior segment is wanting; the pos-
terior segment retaining the name of the transverse process. In the lumbar region,
the anterior segments (which are largely developed) are called the transverse
processes; but, in reality, they are lumbar ribs, the posterior segments or true trans-
verse processes existing in a rudimentary state, and being developed from the supe-
rior articular processes, as in the cervical region. In the cervical region, the
transverse processes are placed in front of the articular processes, and between the
intervertebral foramina. In the lumbar, they are placed also in front of the arti-
cular processes, but behind the intervertebral foramina. In the dorsal region,
they are posterior both to the articular processes and foramina.
The lateral surfaces are separated from the posterior by the articular processes
in the cervical and lumbar regions, and by the transverse processes in the dorsal.
These surfaces present in front the sides of the bodies of the vertebrae, marked in
the dorsal region by the facets for articulation with the heads of the ribs. More
posteriorly are the intervertebral foramina, formed by the juxtaposition of the inter-
vertebral notches, oval in shape, smallest in the cervical and upper part of the dorsal
regions, and gradually increasing in size to the last lumbar. They are situated
between the transverse processes in the neck, and in front of them in the back and
loins, and transmit the spinal nerves. The base of the vertebral column is formed
by the under surface of the body of the fifth lumbar vertebra, and the summit by
the upper surface of the atlas. The vertebral canal follows the different curves of
the spine; it is largest in those regions in which the spine enjoys the greatest free-
dom of movement, as in the neck and loins, where it is wide and triangular; and
narrow and rounded in the back, where motion is more limited.
OCCIPITAL BONE.
19
THE SKULL.
The Skull is divided into two parts, the Cranium and the Face. The Cranium is
composed of eight hones; viz., the occipital, two parietal, frontal, two temporal,
sphenoid, and ethmoid. The Face is composed oi fourteen bones; viz., the two
nasal, two superior maxillary, two lachrymal, two malar, two palate, two inferior
turbinated, vomer, inferior maxillary. The ossicula auditus, the teeth, and Wor-
mian bones, are not included in this enumeration.
Occipital.
Two Parietal.
r ri . ' or J Frontal.
Lramum, 5 bones. ( ~ ^ ,
' ' Two Temporal.
Sphenoid.
Ethmoid.
Two Nasal.
Two Superior Maxillary.
Two Lachrymal.
Two Malar.
Two Palate.
Two Inferior Turbinated.
Vomer.
^ Inferior Maxillary.
The Occipital Bone.
The Occipital Bone (fig. 18) is situated at the posterior and inferior part of the
cranium, is trapezoid in form, curved upon itself, and presents for examination
two surfaces, four borders, and four angles.
18. — Occipital Bone. Outer Surface.
Skull, 22 bones. (
Face, 14 bones.
a/£/uryn-jr.
C 2
20 OSTEOLOGY.
External Surface. Midway between the summit of tlie bone and the posterior
margin of the foramen magnum is a prominent tubercle, the external occipital pro-
tuberance, for the attachment of the ligamentum nuchas; and descending from it,
as far as the foramen, a vertical ridge, the external occipital crest. Passing out-
wards from the occipital protuberance on each side are two semicircular ridges,
the superior curved lines; and running parallel with these fx'om the middle of the
crest, are the two inferior curved lines. The surface of the bone above the supe-
rior curved lines presents on each side a smooth surface, which, in the recent
state, is covered by the occipito-frontalis muscle, whilst the ridges, as well as the
surfaces of the bone between them, serve for the attachment of numerous muscles.
The superior curved line gives attachment internally to the Trapezius, externally
to the Occipito-frontalis, and Sterno-cleido mastoideus; to the extent shewn in the
figure. The depressions between the curved lines to the Complexus internally,
the Splenius capitis and Obliquus superior externally. The inferior curved line,
and the depressions below it, afford insertion to the Rectus capitis posticus, major
and minor.
The foramen magnum is a large aperture, with rounded shelving margins, oblong
in form, and wider behind than in front; it transmits the spinal cord and its mem-
branes, the spinal accessory nerves, and the vertebral arteries. On each side of the
foramen magnum are the occipital condyles, for articulation with the Atlas; they
are convex articular surfaces, oval in form, and directed downwards and out-
wards; they approach each other anteriorly, and encroach more upon the anterior
than the posterior segment of the foramen. On their inner surface is a rough
tubercle, for the attachment of the check ligaments ; whilst external to them is a
rough tubercular prominence, the transverse, or jugular process, channelled in
front by a deep notch, which forms part of the jugular foramen. The under
surface of this process affords attachment to the Rectus capitis lateralis muscle;
its upper or cerebral surface presents a deeply curved groove, which lodges part
of the lateral sinus, whilst its prominent extremity is marked by a quadrilateral
rough surface, covered with cartilage in the fresh state, and articulating with a
similar surface on the petrous portion of the temporal bone. On the outer side of
each condyle is a depression, the anterior condyloid fossa, perforated at the bottom
by the anterior condyloid foramen. This foramen (sometimes double) is directed
downwards outwards, and forwards, and transmits the lingual nerve. Behind each
condyle is seen an irregular fossa, also perforated at the bottom by a foramen, the
posterior condyloid, for the transmission of a vein to the lateral sinus. This fossa
and foramen are less regular in form and size than the anterior, and do not always
exist. Sometimes they are found on one side only, and sometimes are altogether
absent. In front of the foramen magnum is the basilar process, somewhat quadri-
lateral in form, wider behind than in front; its under surface, which is rough,
presenting in the median line a tubercvilar ridge, the pharyngeal spine, for the
attachment of the tendinous raphe and Superior constrictor of the pharynx; and
on each side of it, rough depressions for the attachment of the Recti capitis
antici, major and minor.
The Internal or Cerebral Surface (fig. 19) is deeply concave. The occipital
part is divided by a crucial ridge into four fossse. The two superior, the smaller,
receive the posterior lobes of the cerebrum, and present eminences and depressions
corresponding to their convolutions. The two inferior, which receive the lateral
lobes of the cerebellum, are larger than the former, and comparatively smooth;
both are marked by slight grooves for the lodgment of arteries. At the point of
meeting of the four divisions of the crucial ridge is an eminence, the internal
occipital protuberance, which rarely corresponds to that on the outer surface.
From this eminence, the superior division of the crucial ridge, called sulcus longi-
tudinalis, runs upwards to the superior angle of the bone; it presents a deep
groove for the superior longitudinal sinus, whilst its margins give attachment to
the falx cerebri. The inferior division, the internal occipital crest, runs to the
margin of the foramen magnum, on the edge of which it becomes gradually lost:
OCCIPITAL BONE.
21
this ridge, which is bifurcated below, serves for the attachment of the falx
cerebelli, and is slightly grooved for the lodgment of the occipital sinuses. The
transverse grooves {sulci transver sales) pass outwards to the lateral angles; they
are deeply grooved, for the lodgment of the lateral sinuses, their prominent margins
affording attachment to the tentorium cerebelli. At the point of meeting of these
four grooves is a depression for the torcular Herophili, placed a little to the right
of the internal occipital protuberance. In the centre of the basilar portion of the
bone is the foramen magnum, and above its margin, but nearer its anterior than
its posterior part, the internal openings of the anterior condyloid foramina; the
internal openings of the posterior condyloid foramina being a little external and
posterior to them, and protected above by a small arch of bone. In front of the
foramen magnum is the basilar process, presenting a shallow longitudinal depres-
sion, the basilar groove, for supporting the medulla oblongata; whilst on its lateral
19. — Occipital Bone. Inner Surface.
S ufi e rio -p Amg I e
S u h
Inferior An alp V^
margins is observed a narrow channel on each side, which, when united with
a similar channel on the petrous portion of the temporal bone, forms a groove, the
inferior petrosal, which lodges the inferior petrosal sinus.
Angles. The superior angle is acute, and is received into the interval between
the posterior superior angles of the two parietal bones: it corresponds with that
part of the head in the foetus which is called the posterior fontanelle. The infe-
rior angle is represented by the square-shaped surface of the basilar process. At
an early period of life, a layer of cartilage separates this part of the bone from the
sphenoid; but in the adult, the union between them is osseous. The lateral
22
OSTEOLOGY.
angles correspond to the outer ends of the transverse grooves, and are received into
the interval between the posterior inferior angles of the parietal and the mastoid
portion of the temporal.
Borders. The superior extends on each side from the superior to the lateral angle,
is deeply serrated for articulation with the parietal bone, and forms by this
union the lambdoid suture. The inferior border extends from the lateral to
the inferior angle; its upper half is rough, and articulates with the mastoid por-
tion of the temporal, forming the masto-occipital suture: the inferior half articu-
lates with the petrous portion of the temporal, forming the petro-occipital suture:
these two portions are separated from one another by the jugular process. In
front of this process is a notch, which, with a similar one on the petrous portion
of the temporal, forms the foramen lacerum posterius. This notch is often subdi-
vided into two parts by a small process of bone.
Structure. The occipital bone consists of two compact laminae, called the outer
and inner tables, having between them the diploic tissue; this bone is especially
thick, at the ridges, protuberances, condyles, and basilar process; whilst at the
bottom of the fossae it is thin, semi-transparent, and destitute of diploe.
Development (fig 2o). The occipital bone has seven centres of development;
four for the posterior or occi-
-Development of Occipital Bone.
Jit/ Y centres
at IvriJi
t]?,c Jf- pieces
sevoLrate
If, -for oooiviicul
portion
1 for each condylo
jyorivon
oojuiiLwt portion
:,d
pital part, one for the basilar
portion ; and one for each con-
dyloid portion.
The four centres for the
occipital portion are arranged
in pairs above and below the
occipital protuberance, and
appear about the tenth week
of foetal life; the inferior pair
make their appearance first,
and join ; the superior pair be-
come also united: these two
segments now join together,
and form a single piece. The
condyloid portions then os-
sify; and, lastly, the basilar
portion. At birth, the bone consists of these four parts, separate from one another,
the posterior being fissured in the direction of the original segments. At about
the fourth year, the occipital and the two condyloid pieces join; and at about the
sixth year the bone consists of a single piece. At a later period, between the
eighteenth and twenty-fifth years, the occipital and sphenoid become united,
forming a single bone.
Articulations. With six bones; two parietal, two temporal, sphenoid, and Atlas.
Attachment of Muscles. To the superior curved line are attached the Occipito-
frontalis. Trapezius, and Sterno-cleido-mastoid. To the space between the curved
lines, the Complexus, Splenius capitis, and Obliquus superior; to the inferior curved
line, and the space between it and the foramen magnum, the Rectus posticus ma-
jor and minor; to the transverse process, the Rectus lateralis; and to the basilar
process, the Recti antici majores and minores, and Superior Constrictor of the
pharynx.
The Parietal Bones.
The Parietal Bones form the sides and roof of the skull; they are of an irre-
gular quadrilateral form, and present for examination two surfaces, four borders,
and four angles.
Surfaces. The External Surface (fig. 2l)is convex, smooth, and presents about its
centre an eminence, called the parietal eminence, which indicates the point where
ossification commenced. Crossing the centre of the bone in an arched direction
PARIETAL BONE.
23
is a curved ridge, the temporal ridge, for the attachment of the temporal fascia.
Above this ridge, the surface of the bone is rough and porous, and covered by the
aponeurosis of the Occipito-frontalis; below it the bone is smooth, and affords
2 1 . — Left Parietal Bone. External Surface.
'Pcirte.teiol rm ,
^^f^pORAL imSQ^^
■ ^if-
attachment to the Temporal muscle. At the back part of the superior border is a
small foramen, the parietal foramen, which transmits a vein to the superior longi-
tudinal sinus. Its existence is not constant, and its position varies considerably.
The Internal Surface (iig. 22), concave, presents numerous eminences and
depressions for lodging the convolutions of the brain, and minute furrows for the
ramifications of the meningeal arteries: these run upwards and backwards from
deep grooves, which commence in the anterior inferior angle, and at the central
and posterior part of the lower border of the bone. Along the upper margin is
part of a shallow groove, which, when joined to the opposite parietal, forms a
channel for the superior longitudinal sinus, the elevated edges of which afford
attachment to the falx cerebri. Near the groove are seen several depressions; they
lodge the Pacchionian bodies. The internal opening of the parietal foramen is
also seen when that aperture exists.
Borders. The superior, the longest, is dentated to articulate with its fellow
of the opposite side, forming the sagittal suture. The inferior is divided into
three parts; of these, the anterior is thin and pointed, bevelled at the expense of
the outer surface, and overlapped by the tip of the great wing of the sphenoid;
the middle portion is arched, bevelled at the expense of the outer surface, and
overlapped by the squamous portion of the temporal; the posterior portion being
thick and serrated for articulation with the mastoid portion of the temporal.
The anterior border, deeply serrated, is bevelled at the expense of the outer sur-
face above, and of the inner below; it articulates with the frontal bone, forming
24
OSTEOLOGY.
the coronal suture. The posterior border, deeply denticulated, articulates with
the occipital, foi-ming the lambdoid suture.
Angles. The anterior superior, thiu and pointed, corresponds with that portion
of the skull which in the foetus is membranous, and is called the anterior fon-
tanelie. The anterior inferior angle is thin and lengthened, being received in
the interval between the great wing of the sphenoid and the frontal. Its inner
surface is marked by a deep groove, sometimes a canal, for the middle meningeal
22. — Left Parietal Bone. Internal Surface.
Post.jSup. -^'^A^
K,,%,Amt. Sup
Ancfle
Posl.Iyifer.An^l^
Alii. Infer An,cil&
artery. The posterior superior angle corresponds with the junction of the sagittal
and lambdoid sutures. In the foetus this part of the skull is membranous, and is
called the posterior fontanelle. The posterior inferior articulates with the mas-
toid portion of the temporal bone, and presents on its inner surface a broad
shallow groove for the lateral sinus.
Development. The parietal bone is developed by one centre, which corresponds
with the parietal eminence, and makes its first appearance about the fifth or sixth
week of foetal life.
Articulations. With five bones; the opposite parietal, the occipital, frontal,
temporal, and sphenoid.
Attachment of Muscles. To one only, the Temporal.
The Frontal Bone.
This bone, which resembles a cockle-shell in form, consists of two portions —
a vertical or frontal portion, situated at the anterior part of the cranium, forming
the forehead; and a horizontal or orhito-nasal portion, which enters into the for-
mation of the roof of the orbits and nose.
Vertical Portion. External Surface (fig. 23). In the median line, traversing
the bone from the upper to its lower part, is a slightly elevated ridge, and in
young subjects a suture, which represents the point of union of its two lateral
FRONTAL BONE.
25
halves: in the fidult, this suture usually disappears. On either side of this ridge,
a little below the centre of the bone, is a rounded eminence, the frontal eminence,
which indicates the point where ossification commenced. The whole surface of
the bone above this part is smooth, and covered by the aponeurosis of the Occipito-
frontalis muscle. Below the frontal protuberance, and separated from it by a
slight groove, is the superciliary ridge, a curved eminence, broad internally where
it is continuous with the nasal eminence, less distinct externally as it arches
outwards. Beneath the superciliary ridge is the supra-orbital arch, a curved and
prominent margin, which forms the upper boundary of the orbit, and separates the
vertical from the horizontal portion of the bone. At the inner third of this arch
is a notch, sometimes converted into a foramen by a bony process or ligament, and
23. — Frontal Bone. Outer Surface.
^Internal Easte'r-nat
Anqalar Jiroc, Ancfular hroc.
iXasal Q Shine
called the supra- orbital notch or foramen. It transmits the supra-orbital artery,
veins, and nerve. The supra-orbital arch terminates externally in the external
angular process, and internally in the internal angular process. The external
angular is a strong prominent process, which articulates with the malar: running
upwards and backwards from it is a sharp curved line, the temporal ridge, for the
attachment of the temporal fascia; and beneath it a slight concavity, that forms
part of the temporal fossa, and gives origin to the Temporal muscle. The internal
angular processes are less marked than the external, and articulate with the
lachrymal bones. Between the two is a rough, uneven interval, called the nasal
notch, which articulates in the middle line with the nasal, and on either side with
the nasal process of the superior maxillary bones.
Vertical Portion, Internal Surface (fig. 24). Along the middle line of this
surface is a vertical groove, sulcus longitudinalis, the edges of which unite below
to form a ridge, the frontal crest; the groove lodges the superior longitudinal
sinus, whilst its edges afford attachment to the falx cerebri. The crest terminates
below, at a small opening, the foramen coecum. which is generally completed be-
26
OSTEOLOGY.
hind by the ethmoid; it lodges a process of the falx cerebri, and occasionally
transmits a small vein from the nose to the superior longitudinal sinus. On
either side of the groove, the bone is deeply concave, presenting eminences and
depressions for the convolutions of the brain, and numerous small furrows for
lodging the ramifications of the anterior meningeal arteries. Several small, irregular
fossae are also seen on either side of the groove, for the reception of the Pacchionian
bodies.
Horizontal Portion. External Surface. This portion of the bone consists ot
two thin plates, which form the vault of the orbits, separated from one another by
the ethmoidal notch. Each orbital vault consists of a smooth, concave, trian-
gular plate of bone, marked at its anterior and external part (immediately beneath
the external angular process) by a shallow depression, the lachrymal fossa, for
lodging the lachrymal gland; and at its anterior and internal part, by a de-
pression, sometimes a tubercle, for the ' attachment of the fibrous pulley of the
superior oblique muscle. The ethmoidal notch separates the two orbital plates: it
24. — Frontal Bone. Inner Surface.
,r/^^•
with Swp.Maxill.
with. Na/sn 7
VL'ith Ferpendieular ylute of Etlnnoid
FrontaZ S'inus
EjLpandod hase of Najftcul SjJiyie,
formtnq part trf Moirf^ ef ISjse
is quadrilateral; and filled up, when the bones are united, by the cribriform plate
of the ethmoid. The edges of this notch present several half-cells, which, when
united with corresponding half-cells on the upper surface of the ethmoid, com-
plete the ethmoidal cells : two grooves are also seen crossing these edges trans-
versely; they are converted into canals by articulation with the ethmoid, and are
called the anterior and posterior ethmoidal canals; they open on the inner wall
of the orbit. In front of the ethmoidal notch is the nasal spine, a sharp eminence,
which projects downwards and forwards, and the grooved base of which forms
part of the roof of the nose. It articulates in front with the crest of the nasal
bones, behind with the perpendicular plate of the ethmoid. On either side of this
spine are the openings of the frontal sinuses. These are two irregular cavities,
TEMPORAL BONE.
27
which extend upwards and outwards, a variable distance, between the two tables
of the skull, and are separated from one another by a thin bony septum. They
give rise to the prominences above the root of the nose, called the nasal
eminences. In the child they are absent, and they become gradually developed
as age advances. They are lined by mucous membrane, and communicate with
the nose by the infundibulum.
The Internal Surface of the Horizontal Portion presents the convex upper
surfaces of the orbital plates, separated from each other in the middle line by the
ethmoidal notch, and marked by eminences and depressions for the convolutions of
the anterior lobes of the brain.
Borders. The border of the vertical portion is thick, strongly serrated, bevelled
at the expense of the internal table above, where it rests upon the parietal, at the
expense of the external table at each side, where it receives the lateral pressure
of those bones: this border is continued below, into a triangular rough surface,
which articulates with the great wing of the sphenoid. The border of the
horizontal portion is thin, bevelled at the expense of the internal table, and
articulates with the lesser wing of the sphenoid.
Structure. The vertical portion consists of diploic tissue, contained between
two compact laminae, the bone being especially thick in the situation of the nasal
eminences and external angular processes. The horizontal portion is thinner,
more translucent, and composed entirely of compact tissue.
Development. The frontal bone is developed by two centres, one for each lateral
half, which make their appearance, at an early period of foetal life, in the situation
of the orbital arches. At birth it consists of two pieces, which afterwards become
united along the middle line, by a suture which runs from the vertex to the root
of the nose. This suture becomes obliterated within a few years after birth; but
it occasionally remains throughout life.
Articulations. With twelve bones ; two parietal, sphenoid, ethmoid ; two nasal,
two superior maxillary, two lachrymal, and two malar.
Attachment of Muscles. To three pairs; the Corrugator supercilii. Orbicularis
palpebrarum, and Temporal.
The Temporal Bones.
The Temporal bones, situated at the side and base of the skull, present for
examination a squamous, mastoid, and petrous portion.
The Squamous Portion (fig. 25), the most anterior and superior part of the
bone, is flattened and scale-like in form, thin and translucent in texture. Its
outer surface is smooth, convex, and grooved for the deep temporal arteries; it
affords attachment to the fibres of the Temporal muscle, and forms part of the tem-
poral fossa. At its back part may be seen a curved ridge — part of the temporal
ridge; it serves for the attachment of the temporal fascia, limits the origin of
the Temporal muscle, and marks the boundary between the squamous and mastoid
portions of the bone. Projecting from the lower part of the squamous portion,
is a long and arched process of bone, the zygomatic process. It is at first
directed outwards, its two surfaces looking upwards and downwards; it then
appears as if twisted upon itself, and takes a direction forwards, its surfaces now
looking inwards and outwards. The superior border of this process is long, thin,
and sharp, and serves for the attachment of the temporal fascia. The inferior,
short, thick, and arched, has attached to it some of the fibres of the Masseter
muscle. Its outer surface is convex and subcutaneous. Its inner, concave, also
affords attachment to the Masseter. The extremity, broad and deeply serrated,
articulates with the malar bone. This process is connected to the temporal bone
by three divisions, called the roots of the zygomatic process, an anterior, middle,
and posterior. The anterior, which is short, but broad and strong, runs trans-
versely inwards into a rounded eminence, the eminentia articularis. This eminence
forms the front boundary of the glenoid fossa, and in the recent state is covered
with cartilage. The middle root runs obliquely inwards, and terminates at the
28
OSTEOLOGY.
edge of a well-marked fissure, the Glaserian fissure; whilst the posterior, which
is strongly marked, runs from the upper border of the zygoma, in an arched
direction, upwards and backwards, forming the posterior part of the temporal
ridge. At the junction of the anterior and middle roots is a projection, called the
tubercle, for the attachment of the external lateral ligament of the lower jaw;
and between these roots is a large oval depression, forming part of the glenoid
fossa, for the reception of the condyle of the lower jaw. This fossa is bounded
in front by the eminentia articularis; behind, by the vaginal process; and exter-
nally by the auditory process; and is divided into two parts by a narrow slit, the
Glaserian fissure: the anterior part, formed by the squamous portion of the bone
is smooth, covered in the recent state with cartilage, and articulates with the
condyle of the lower jaw; the posterior part, rough and uneven, and formed
chiefly by the vaginal process of the petrous portion, lodges part of the parotid
gland. The Glaserian fissure, dividing' the two, leads into the tympanum; it
25. — Left Temporal Bone. Outer Surface.
Masto'i d/ -forajnefi
lodges the processus gracilis of the malleus, and transmits the laxator tympani
muscle and the anterior tympanic artery. The chorda tympani nerve passes
through a separate canal parallel to the Glaserian fissure, on the outer side of the
Eustachian tube, in the retiring angle between the squamous and petrous portions
of the temporal bone.
The internal surface of the squamous portion (fig. 26) is concave, presents nu-
merous eminences and depressions for the convolutions of the cerebrum, and two
well marked grooves for the branches of the middle meningeal artery.
Borders. The superior border is thin, bevelled at the expense of the internal
surface, so as to overlap the lower border of the parietal bone, forming the
squamous suture. The anterior inferior border is thick, serrated, and bevelled
alternately at the expense of the inner and outer surfaces, for articulation with the
great wing of the sphenoid.
TEMPORAL BONE.
29
The Mastoid Portion is situated at the posterior part of the bone, its outer
surface is rough, and perforated by numerous foramina, one of these, of large size,
situated at the posterior border of the bone, is termed the mastoid foramen, it
transmits a vein to the lateral sinus and a small artery. The position and size
of this foramen are very variable, being sometimes situated in the occipital bone,
or in the suture between it and the occipital. The mastoid portion is continued
below into a conical projection, the mastoid process, the size and form of which
varies considerably in different individuals. This process serves for the attach-
ment of the Sterno-mastoid, Splenius capitis and Trachelo-mastoid (see fig. 25);
on the inner side of the mastoid process is a deep groove, the digastric fossa, for
the attachment of the Digastric muscle, and running parallel with it, but more
internal, the occipital groove, which lodges the occipital artery. The internal
surface presents a deeply curved groove which lodges the lateral sinus, and into
it may be seen opening the mastoid foramen.
26. — Left Temporal Bone, Inner Surface.
rie ta I
Dcprcvsivn for Dara-nvatenr
]}Ieatas yiv^iCarins iriiei-nus
-Bmi-ntiicc Jot S'uperCor S6mti:ircuia,T Ca.7ia0
Jliatus JFaUopw
O^oniTifj for iSivalhr Petrosal JVcri-c
JicoressioTi fitr Casseriaji gaiifflto-n
Bristle passed thTOiujh Carotid Canal
Borders. The superior border of the mastoid portion is rough and serrated for
articulation with the posterior inferior angle of the parietal bone. The posterior
border, also uneven and serrated, articulates with the inferior border of the occi-
pital bone between its lateral angle and jugular process.
The Petrous Portion, so named from its extreme density and hardness, is a
pyramidal process of bone, wedged in at the base of the skull between the sphenoid
and occipital bones. Its direction from without is forwards, inwards, and a little
downwards. It presents for examination a base, an apex, three surfaces, and
three borders. The base is applied against the internal surface of the squamous
and mastoid portions, its upper half being concealed, but its lower half is exposed
by their divergence, which brings into view the oval expanded orifice of a canal
leading into the tympanum, the meatus auditorius externus. This canal is situated
between the mastoid process and the posterior and middle roots of the zygoma; its
upper margin is smooth and rounded, its lower surrounded by a curved plate of
30 OSTEOLOGY.
bone, tlie auditory process, the free margin of which is rough for the attachment
of the cartilage of the ear. The apex of the petrous portion, rough and uneven,
is received into the angular interval between the spinous process of the sphenoid,
and the basilar process of the occipital; it presents the anterior orifice of the
carotid canal, and forms the posterior and external boundary of the foramen
lacerum medium. The anterior surface (fig. 26) of the petrous portion, forms the
posterior boundary of the middle fossa of the skull. This surface is continuous
with the squamous portion, to which it is united by a suture, the temporal suture,
the remains of which are distinct at a late period of life. Proceeding from the
base to the apex, this surface presents five points for examination. i. An
eminence which indicates the situation of the superior semicircular canal. 2. A
shallow groove, sometimes double, leading backwards to an oblique opening, the
hiatus Fallopii, for the passage of the petrosal branch of the Vidian nerve. 3. A
smaller opening immediately beneath and external to the latter for the passage of
the smaller petrosal nerve. 4. Near the apex of the bone is seen the termination
of the carotid canal, the wall of which in this situation is deficient in front. 5. Above
the foramen is a shallow depression for the reception of the Gasserian ganglion.
The posterior surface forms the front boundary of the posterior fossa of the
skull, and is continuous with the inner surface of the mastoid portion of the bone.
It presents three points for examination, i. About its centre is a large orifice,
the meatus auditorius internus. This aperture varies considerably in size, its
margins are smooth and rounded, and it leads into a short and oblique canal
which is directed outwards and forwards. It transmits the auditory and facial
nerves and auditory artery. 2. Behind the meatus auditorius is a small slit almost
hidden by a thin plate of bone, and leading to a 'canal, the aquseductus vestibuli;
it transmits a small artery and vein, and lodges a process of the dura mater.
3. In the interval between these two openings, but above them, is an angular
depression which lodges a process of the dura mater, and transmits a small vein
into the cancellous tissue of the bone.
The inferior or basilar Surface (fig. 27) is rough and irregular, and forms
part of the base of the skull. Passing from the apex to the base, this surface
presents eleven points for examination; I. A rough surface, quadrilateral in form,
which serves partly for the attachment of the Levator palati, and Tensor tympani
muscles. 2. The opening of the carotid canal, a large circular aperture, which
ascends at first vertically upwards, and then making a bend, runs horizontally
forwards and inwards. It transmits the internal carotid artery, and the carotid
plexus. 3. The aquseductus cochleae, a small triangular opening, lying on the
inner side of the latter, close to the posterior border of the bone; it transmits a
vein from the cochlea, which joins the internal jugular. 4. Behind these openings
is a depression, the jugular fossa, which varies in depth and size in different skulls;
it lodges the internal jugular vein, and with a similar depression on the margin
of the occipital bone, forms the foramen lacerum posterius. 5. A small foramen
for the passage of Jacobson's nerve (the tympanic branch of the glosso-pharyngeal).
This is seen on the ridge of bone dividing the carotid canal from the jugular fossa.
6. The canal for Arnold's nerve, seen on the inner wall of the jugular fossa.
7. Behind the jugular fossa is a smooth square-shaped facet, the jugular surface,
which articulates with the jugular process of the occipital bone. 8. The vaginal
process, a very broad sheath-like plate of bone, which extends from the carotid
canal to the mastoid process; it divides behind into two laminae, receiving between
them the 9th point for examination, the styloid process; a long sharp spine, about
an inch in length, continuous with the vaginal process, between the laminag of
which it is received, and directed downwards, forwards, and inwards. It affords
attachment to three muscles, the Stylo-pharyngeus, Stylo-glossus, and Stylo-hyoideus,
and two ligaments, the stylo-hyoid and stylo-maxillary. lO. The stylo-mastoid
foramen, a rather large orifice, placed between the styloid and mastoid processes;
it is the termination of the aquseductus Fallopii, and transmits the facial nerve
and stylo-mastoid artery. 11. The auricular fissure, situated between the vaginal
THE TEMPORAL BONE.
31
and mastoid processes, and transmitting the auricular branch of the pneumo-
gastric nerve.
Borders. The superior, the longest, is grooved for the superior petrosal sinus,
and has attached to it the tentorium cerebelli: at its inner extremity is a semilunar
notch, upon which reclines the fifth nerve. The posterior border is intermediate
in length between the superior and the anterior. Its inner half is marked by a
groove, which, when completed by its articulation with the occipital, forms the
channel for the inferior petrosal sinus. Its outer half presents a deep excavation
2.7. — Petrous Portion. Inferior Surface.
CavalsforlAisla-ohiaTi ttiie
atiJ' Tensor tYmpani wusc '
LEVATOR PALAT
RcriLCjh Quadrilafera/' /SuT^a-ce
Upe.vLiia of carctid ecriial
Canal' far Jarohwns nerve
Aqupdiicriis Cor/date,
Canal far Arnold's Tierve
JziifvJar josscc
Yncjvnal ^ocess
Stf^lmd proeess
^tiilo' mastoid foTctvien
JiL^QiJaT Si'rfaee
AuricuIaT fissure
STYLO -PHARrNGEUS
for the jugular fossa, which, with a similar notch on the occipital, forms the fora-
men lacerum posterius. A projecting eminence of bone occasionally stands out
from the centre of the notch, and divides the foramen into two parts. The ante-
rior border is divided into two parts, an outer, joined to the squamous portion by
a suture the remains of which are distinct; an inner, free, articulating with the
spinous process of the sphenoid. At the angle of junction of these two parts, are
. seen two canals, separated from one another by a thin plate of bone, the processus
cochleariformis; they both lead into the tympanum, the upper one transmitting the
Tensor tympani muscle, the lower one the Eustachian tube.
Structure. The squamous portion is like that of the other cranial bones, the
mastoid portion cellular, and the petrous portion dense and hard.
Development (fig. 28). The temporal bone is developed hjfour centres, exclusive
of those for the internal ear and the ossicula, viz.; — one for the squamous portion
including the zygoma, one for the petrous and mastoid parts, one for the styloid,
and one for the auditory process (tympanic bone). The first traces of the develop-
ment of this bone are found in the squamous portion, they appear about the time
when osseous matter is deposited in the vertebree; the auditory process succeeds
32
OSTEOLOGY.
next, it consists of an elliptical portion of bone, forming about three-fourths of a
circle, the deficiency being above; it is grooved along its concave surface for the
zZ. — Development of Temporal Bone.
By four Centres.
1 for Sq^ua-viows
foTtixm, mcludi;,
Zvaama
Z^ mo
I for Auditor II
1 fof Pctroiis
portions
£ fov StyloicL prvc.
attachment of the membrana tympani,
and becomes united by its extremities
to the squamous portion during the last
months of intra-uterine life. The pe-
trous and mastoid portions then become
ossified, and lastly the styloid process,
which remains separate a considerable
period, and is occasionally never united
to the rest of the bone. At birth the
temporal bone, excluding the styloid
process, is formed of three pieces, the
squamous and zygomatic, the petrous
and mastoid, and the auditory. The
auditory process joins with the squa-
mous at about the ninth month. The
petrous and mastoid join with the squa-
mous during the first year, and the sty-
loid process becomes united between
the second and third years. The sub-
sequent changes in this bone are the
extension outwards of the auditory
process so as to form the meatus audi-
torius, the glenoid fossa becomes deeper,
and the mastoid part enlarges from the development of numerous cellular cavities
in its interior.
Articulatio7is. With five bones, occipital, parietal, sphenoid, inferior maxil-
lary and malar.
Attachment of Muscles. To the squamous portion, the Temporal; to the zygoma,
the Masseter; to the mastoid portion, the Occipito-frontalis, Sterno-mastoid, Splenius
capitis, Trachelo -mastoid, Digastricus and Retrahens aurem; to the styloid j)i*ocess,
the Stylo-pharyngeus, Stylo-hyoideus and Stylo-glossus; and to the petrous portion,
the Levator palati. Tensor tympani, and Stapedius.
The Sphenoid Bone.
The Sphenoid (cr^rjv, a 'wedge'; eiSo9, 'like') is situated at the anterior part of
the base of the skull, articulating with all the other cranial bones, which it binds
firmly and solidly together. Li its form it somewhat resembles a bat, with its
wings extended; and is divided into a central portion or body, two greater and
two lesser wings extending outwards on each side of the body; and two processes,
the pterygoid processes, which project from it below.
The Body presents for examination ybwr surfaces — a superior, an inferior, an
anterior, and a posterior.
The superior surface (fig. 29). From before, backwards, is seen a prominent
spine, the ethmoidal spine, for articulation with the ethmoid; behind this a smooth
surface, presenting in the median line a slight longitudinal eminence, with a de-
pression on each side, for lodging the olfactory nerves. A narroAV transverse
groove, the optic groove, bounds the above-mentioned surface behind ; it lodges the
optic commissure, and terminates on either side in the optic foramen, for the pas-
sage of the optic nerve and ophthalmic artery. Behind the optic groove is a
small eminence, olive-like in shape, the olivaiy process; and still more posteriorly,
a deep depression, the pituitary fossa, or sella Turcica, which lodges the pituitary
body. This fossa is pei'forated by numerous foramina, for the transmission of nu-
trient vessels to the substance of the bone. It is bounded in front by two small
eminences, one on either side, called the middle clinoid processes, and behind by
a squai'e- shaped plate of bone, terminating at each superior angle in a tubercle, the
SPHENOID BONE.
33
posterior clinoid processes, the size and form of which vary considerably in different
individuals. The sides of this plate of bone are notched below, for the passao-e of
the sixth pair of nerves; and behind, it presents a shallow depression, which slopes
29. — Sphenoid Bone, Superior Surface,
JPustcrior
MiMiii CUiiocd process . , _ .„
/^/- J \ UtJimoudaT Spiv&
nor LUrwid process \ ^ ^ 1 ■'
(h'oat/ejor
■JjO'T^
J!ammen Opdcw
loramov, laceravi
U£Tt'us, err S'jihvnoitialFCsswre
forxvwn JRctimda
H VmiMu
„ Oualo
II Sfi'nasa.-M
obliquely backwards, and is continuous with the basilar groove of the occipital
bone; it supports the medulla oblongata. On either side of the body may be seen
a broad groove, curved somewhat like the italic letter y"; it lodges the internal
30. — Sphenoid Bone, Anterior Surface.
JPtf-rycfoici
LAXATOR TYMPANI
Zntcvnal Tti7-ifef>
JSiwmuZtt/i:' /i/faccss
carotid artery and the cavernous sinus, and is called the cavernous groove. The
posterior surface, quadrilateral in form, articulates with the basilar process of the
occipital bone. During childhood, a separation between these bones exists by
means of a layer of cartilage; but in after-life this becomes ossified, and the two
bones are immoveably connected together. The anterior surface (fig, 30) presents,
m the middle line, a vertical lamella of bone, which articulates in front with the
34 OSTEOLOGY.
perpendicular plate of the ethmoid. On either side of it are the irregular openings
leading into the sphenoidal sinuses. These are two large, irregvilar cavities, hol-
lowed out of the interior of the body of the sphenoid bone, and separated from
one another by a more or less complete perpendicular septum; their form varies
considerably, being often subdivided by irregular osseous laminae. These sinuses
do not exist in children; but they increase in size as age advances. They are
partially closed, in front and below, by two thin triangular plates of bone, the
sphenoidal turbinated bones, leaving a round opening at their upper parts, by
which they communicate with the upper and back part of the nose, and occa-
sionally with the posterior ethmoidal cells. The lateral margins of this surface
present a serrated edge, which articulates with the os planum of the ethmoid,
completing the posterior ethmoidal cells ; the lower margin, also rough and serrated,
articulates with the orbital process of the palate bone; and the upper margin
with the orbital plate of the frontal bone. The inferior surface presents, in the
middle line, a triangular spine, the rostrum, which is continuous with the vertical
plate on the anterior surface, and is received into a deep fissure between the alae
of the vomer. On each side may be seen a projecting lamina of bone, which runs
horizontally inwards from near the base of the pterygoid process: these plates,
termed the vaginal processes, articulate with the edges of the vomer. Close to the
root of the pterygoid process is a groove, formed into a complete canal when articu-
lated with the sphenoidal process of the palate bone ; it is called the pterygo-pala-
tine canal, and transmits the pterygo-palatine vessels and pharyngeal nerve.
The Greater Wings are two strong processes of bone, which arise at the sides
of the body, and are curved in a direction upwards, outwards, and backwards;
being prolonged behind into a sharp-pointed extremity, called the spinous process
of the sphenoid. Each wing presents three surfaces and a circumference. The
superior or cerebral surface forms part of the middle fossa of the skull; it is
deeply concave, and presents eminences and depressions for the convolutions of
the, brain. At its anterior and internal part is seen a circular aperture, the
foramen rotundum, for the transmission of the second division of the fifth nerve.
Behind and external to this, a large oval foramen, the foramen ovale, for the trans-
mission of the third division of the fifth, the small meningeal artery, and the small
petrosal nerve. At the inner side of the foramen ovale, a small aperture may
occasionally be seen opposite the root of the pterygoid process; it is the foramen
Vesalii, transmitting a small vein. Lastly, in the apex of the spine of the sphe-
noid is a short canal, sometimes double, the foramen spinosum; it transmits the
middle meningeal artery. The external surface is convex, and divided by a trans-
verse ridge, the pterygoid ridge, into two portions. The superior or larger,
convex from above downwards, concave from before backwards, enters into the
formation of the temporal fossa, and attaches part of the Temporal muscle. The
inferior portion, smaller in size and concave, enters into the formation of the
zygomatic fossa, and afibrds attachment to the External pterygoid muscle. It
presents, at its posterior part, a sharp-pointed eminence of bone, the spinous
process, to which is connected the internal lateral ligament of the lower jaw, and
the Laxator tympani muscle. The pterygoid ridge, dividing the temporal and
zygomatic portions, gives attachment to the upper origin of the External ptery-
goid muscle. At its inner extremity is a long triangular spine of bone, which
serves to increase the extent of origin of this muscle. The anterior or orbital
surface, smooth and quadrilateral in form, assists in forming the outer wall of the
orbit. It is bounded above by a serrated edge, for articulation with the frontal
bone; below, by a rounded border, which enters into the formation of the spheno-
maxillary fissure; internally, it enters into the formation of the sphenoidal fissure;
whilst externally it presents a serrated margin, for articulation with the malar
bone. At the upper part of the inner border is a notch, for the transmission of a
branch of the ophthalmic artery; and at its lower part a small pointed spine of
bone, which serves for the attachment of part of the lower head of the external
rectus. One or two small foramina may occasionally be seen, for the passage of
'
SPHENOID BONE.
35
arteries; tliey are called the external orhitar foramina. Circumference: from
the body of the sphenoid to the spine (commencing from behind), the outer half of
this margin is serrated, for articulation with the petrous portion of the temporal
bone; whilst the inner half forms the anterior boundary of the foramen lacerum
medium, and presents the posterior aperture of the Vidian canal. In front of the
spine, the circumference of the great wing presents a serrated edge, bevelled at
the expense of the inner table below, and of the external above, which articulates
with the squamous portion of the temporal bone. At the tip of the great wing
a triangular portion is seen, bevelled at the expense of the internal surface, for
articulation with the anterior inferior angle of the parietal bone. Internal to this
is a broad serrated edge, for articulation with the frontal bone: this surface is
continuous internally with the sharp inner edge of the orbital plate, which assists
in the formation of the sphenoidal fissure.
The Lesser Wings (processes of Ingrassias) are two thin triangular plates of
bone, which arise from the upper and anterior part of the body of the sphenoid;
and, projecting transversely outwards, terminate in a more or less acute point.
The superior surface of each is smooth, flat, broader internally than externally, and
supports the anterior lobe of the brain. The inferior surface forms the back part
of the roof of the orbit, and the upper boundary of the sphenoidal fissure, or
foramen lacerum anterius. This fissure is of a triangular form, and leads from the
cavity of the cranium into the orbit; it is bounded internally by the body of the
sphenoid; above, by the lesser wing; and below, by the orbital surface of the
great wing ; and is converted into a foramen by the articulation of this bone with
the frontal. It transmits the third, fourth, ophthalmic division of the fifth and
sixth nerves, and the ophthalmic vein. The anterior border of the lesser wing
is serrated, for articulation with the frontal bone ; the posterior, smooth and
rounded, is received into the fissure of Sylvius of the brain. The inner extremity
of this border forms the anterior clinoid process. The lesser wing is connected to
the side of the body by two roots, the upper thin and flat, the lower thicker,
obliquely directed, and presenting on its outer side a small tubercle, for the attach-
ment of the common tendon of the muscles of the eye. Between the two roots
is the optic foramen, for the transmission of the optic nerve and ophthalmic artery.
The Pterygoid processes „ , . , ^ -n. , . r^ ^
fr. X 1-1 31. — Sphenoid Bone. Posterior Surface,
(tig. 31), one on each side, ^ ^
descend perpendicularly from
the point where the body and
great wing unite. Each pro-
cess consists of an external
and an internal plate, sepa-
rated behind by an intervening
notch; but joined partially in
front. The external pterygoid
plate is broad and thin, turned a
little outwards, and forms part
of the inner wall of the zygo-
matic fossa. It gives attach-
ment, by its outer surface, to
the External pterygoid; its
inner surface forms part of
the pterygoid fossa, and gives attachment to the Internal pterygoid. The internal
pterygoid plate is much narrower and longer, curving outwards at its extremity,
into a hook-like process of bone, the hamular process, around which turns the
tendon of the Tensor-palati muscle. At the base of this plate is a small, oval,
shallow depression, the scaphoid fossa, from which arises the Tensor-palati, and
above which is seen the posterior orifice of the Vidian canal. The outer surface
of this plate forms part of the pterygoid fossa, the inner surface forming the outer
boundary of the posterior aperture of the nares. The two pterygoid plates are
D 2
36 OSTEOLOGY.
separated below by an angular notch, in which the pterygoid process, or tuberosity,
of the palate bone is received. The anterior surface of the pterygoid process is
very broad at its base, and supports Meckel's ganglion. It presents, above, the
anterior orifice of the Vidian canal ; and below, a rough margin, which articulates
with the perpendicular plate of the palate bone.
Development. The sphenoid bone is developed by ten centres, six for the pos-
terior sphenoidal division, and four for 32. — Development of Sphenoid,
the anterior sphenoid. The six centres By Ten Centres.
for the post-sphenoid are, one for each I for eacl lesser wi:n^UA7iirj,a.rt,fiody
greater wing and external pterygoid plate;
one for each internal pterygoid plate;
two for the posterior part of the body.
The four for the anterior sphenoid are,
one for each lesser wing and anterior part
of the body; and one for each sphenoidal
turbinated bone. Ossification takes place ,, i „S^*„«r,n Sr ^^-tZ-r„S'^/i,„
in these pieces in the following order: the
greater wing and external pterygoid plate ^, ,„, .t,, ,- j i
° „ -° , .„ , ,. J^joruich SpmiufumL tiirbi.nate.d bone
are first formed, ossmc granules being
deposited close to the foramen rotundum on each side, at about the second month
of foetal life ; ossification spreading outwards into the great wing, and downwards
into the external pterygoid process. Each internal pterygoid plate is then formed,
and becomes united to the external about the middle of foetal life. The two
centres for the posterior part of the body appear as separate nuclei, side by side,
beneath the sella Turcica; they join about the middle of foetal life into a single
piece, which remains ununited to the rest of the Taone until after birth. Each lesser
wing is foi'med by a separate centre, which appears on the outer side of the optic
foramen, at about the third month; they become united and join with the body,
at about the eighth month of foetal life. At about the end of the third year,
ossification has made its appearance in the sphenoidal spongy bones.
At birth, the sphenoid consists of three pieces; viz. the greater wing and ptery-
goid processes on each side; the lesser wings and body united. At the first
year after birth, the greater wings and body are united. From the tenth to the
twelfth year, the spongy bones commence their junction to the sphenoid, and be-
come completely united by the twentieth year. Lastly, the sphenoid joins the
occipital.
Articulations. The sphenoid articulates with all the bones of the cranium, and
five of the face; the two malar, two palate, and vomer: the exact extent of articu-
lation with each bone is shewn in the accompanying figures.
Attachment of Muscles. The Temporal, External pterygoid. Internal pterygoid,
Superior constrictor, Tensor-palati, Laxator-tympani, Levator-palpebrge, Obliquus
superior, Superior rectus. Internal rectus. Inferior rectus, External rectus. For the
exact attachment of the muscles of the eye to the sphenoid bone, see fig. 133.
The Sphenoidal Spongy Bones.
The Sphenoidal Spongy Bones are two thin, curved plates of bone, which
exist as separate pieces up to the fifteenth year. They are situated at the anterior
and inferior part of the body of the sphenoid, serving to close in the sphenoidal
sinuses in this situation. They are irregular in form, thick, and tapering to a
point behind, broader and thinner in front. Their inner surface, which looks
towards the cavity of the sinus, is concave; their outer surface convex. Each
bone articulates in front with the ethmoid, an aperture of variable size being left
in their anterior wall, which communicates with the posterior ethmoidal cells:
behind, its point is placed under the vomer, and is received between the root of
the pterygoid process on the outer side, and the rostrum of the sphenoid on the
inner: externally, it articulates with the palate.
ETHMOID BONE.
37
wM infjturbinated i.
The Ethmoid.
The Ethmoid {r)6^o^, a sieve), is an exceedingly light spongy bone, of a cubical
form, situated at the anterior part of the base of the cranium, between the two
orbits,''at the root of the nose. ^^. . *-^ ^ ^ „ , ,
It consists of three parts: a 33— Ethmoid Bone. Outer Surface (enlarged).
horizontal plate, which forms *^
part of the base of the cra-
nium; a perpendicular plate,
which forms part of the sep-
tum nasi; and two lateral
masses of cells.
The Horizontal or Cribri-
form Plate (fig.33) forms part
of the anterior fossa of the
base of the skull, and is re-
ceived into the ethmoid notch
of the frontal bone between
the two orbital plates. Pro-
jecting upwards from the
middle line of this plate, at its
fore part, is a thick smooth
triangular process of bone,
the crista galli,so called from its resemblance to a cock's-comb. Its base joins the
cribriform plate. Its posterior border, long, thin, and slightly curved, serves for
the attachment of the falx cerebri. Its anterior, short and thick, articulates with
the frontal bone, and presents at its lower part two small projecting alse, which
are received into corresponding depressions in the frontal, completing the foramen
coecum behind. Its sides are smooth, and sometimes bulging, when it is found to
enclose a small sinus. On each side of the crista galli, the cribriform plate is
concave, to support the bulb of the olfactory nerves, and perforated by numerous
foramina for the passage of its filaments. These foramina consist of three sets,
corresponding to the three sets of olfactory nerves; an inner, which are lost in
grooves on the upper part of the septum; an outer set, continued on to the surface
of the upper spongy bones; whilst the middle set run simply through the bone,
and transmit nerves distributed to the roof of the nose. At the front part of
the cribriform plate, by the side of the crista galli, is a small fissure, which trans-
mits the nasal branch of the ophthalmic nerve; and at its posterior part a trian-
gular notch, which receives the ethmoidal spine of the sphenoid.
P^a^/(fig. r/)'!? ^thin 34.-Perpendicular Plate of Ethmoid (enlarged). Shewn by
V &• i't) *^ ^ ''■L1J-" removing the Right Lateral Mass.
central lamella of bone,
which descends from the
under surface of the
cribriform plate, and
assists in forming the
septum of the nose. Its
anterior border articu-
lates with the frontal
spine and crest of the
nasal bones. Its poste-
rior, divided into two
parts, is connected by
its upper half with the
rostrum of the sphe-
noid; its lower half with
the vomer. The infe-
{fji EthmoicJ,
38 OSTEOLOGY.
rior border serves for the attachment of the triangular cartilage of the nose.
On each side of the perpendicular plate numerous grooves and canals are seen,
leading from the foramina on the cribriform plate ; they lodge the filaments of the
olfactory nerves.
The Lateral Masses of the ethmoid are made up of a numbei" of thin walled
cellular cavities, called the ethmoidal cells. In the disarticulated bone, many
of these appear to be broken ; but when the bones are articulated, they are closed
in in every part. The superior surface of each lateral mass presents a number of
these apparently half-broken cellular spaces; these, however, are completely closed
in when articulated with the edges of the ethmoidal fissure of the frontal bone.
Crossing this surface are seen two grooves on each side, converted into canals by
articulation with the frontal; they are the anterior and posterior ethmoidal fora-
mina. They open on the inner wall of the orbit, and transmit; the anterior, the
anterior ethmoidal vessels and nasal nerve; the posterior, the posterior ethmoidal
artery and vein. The posterior surface also presents large irregular cellular
cavities, which are closed in by articulation with the sphenoidal turbinated bones,
and orbital process of the palate. The cells at the anterior surface are completed
by the lachrymal bone and nasal process of the superior maxillary, and those
below also by the superior maxillary. On the outer surface of each lateral mass
is a thin smooth square plate of bone, called the os planum; it forms part of the
inner wall of the orbit, and articulates above with the frontal; below, with the
superior maxillary and orbital process of the palate; in front, with the lachrymal;
and behind, with the sphenoid.
The cellular cavities of each lateral mass, thus walled in by the os planum on
the outer side, and by its articulation with the other bones already mentioned, are
divided by a thin transverse bony partition into two sets, which do not commu-
nicate with each other; they are termed the anterior and posterior ethmoidal
cells; the former, the most numerous, communicate with the frontal sinuses above,
and the middle meatus below, by means of a long flexuous cellular canal, the
infundibulum ; the posterior, the smallest and least numerous, open into the supe-
rior meatus, and communicate (occasionally) with the sphenoidal sinuses behind. If
the inner wall of each lateral mass is now examined, it will be seen how these
cellular cavities communicate with the nose. The internal surface of each lateral
mass presents, at its upper and back part, a narrow horizontal fissure, the supe-
rior meatus of the nose, bounded above by a thin curved plate of bone, the
superior turbinated bone of the ethmoid. By means of an orifice at the top part
of this fissure, the posterior ethmoidal cells open into the nose. Below the superior
meatus is seen the convex surface of another thin convoluted plate of bone, the
middle turbinated bone. It extends along the whole length of the inner wall of
each lateral mass; its lower margin is free and thick, and its concavity, directed
outwards, assists in forming the middle meatus. It is by means of a large orifice
at the upper and front part of this fissure, that the anterior ethmoid cells, and
through them the frontal sinuses, by means of a funnel-shaped canal, the infundi-
bulum, communicate with the nose. It will be remarked, that the whole of this
surface is rough, and marked with numerous grooves and orifices, which run
nearly vertically downwards from the cribriform plate; they lodge the branches
of the olfactory nerve, which are distributed on the mucous membrane covering
this surface. From the inferior part of each lateral mass, immediately beneath
the OS planum, there projects downwards and backwards an irregular lamina of
bone, called the unciform process, from its hook-like form: it serves to close in
the upper part of the orifice of the antrum, and articulates with the inferior turbi-
nated bone.
Development. By three centres; one for the perpendicular lamella, and one for
each lateral mass.
The lateral masses are first developed, ossific granules making their first appear-
ance in the os planum between the fourth and fifth months of foetal life, and
afterwards in the spongy bones. At birth, the bone consists of the two lateral
WORMIAN BONES.
39
masses, which are small and ill-developed; but when the perpendicular and hori-
zontal plates begin to ossify, as they do about the first year after birth, the lateral
masses become joined to the cribriform plate. The formation and increase in the
ethmoidal cells, which complete the formation of the bone, take place about the
fifth or sixth year.
Articulations. With fifteen bones; the sphenoid, two sphenoidal turbinated, the
frontal, and eleven of the face — two nasal, two superior maxillary, two lachry-
mal, two palate, two inferior turbinated, and vomer.
The Wormian Bones.
The Wormian* bones, called also, from their generally triangular form, ossa
triquetra, are irregular plates of bone, presenting much variation in situation,
number, and size. They are most commonly found in the course of the sutures,
especially the lambdoid and sagittal, where they occasionally exist of large size;
the superior angle of the occipital, and the anterior superior angle of the parietal,
being occasionally replaced by large Wormian bones. They are not limited to the
■vertex, for they are occasionally found at the side of the skull, in the situation of
the anterior inferior angle of the parietal bone, and in the squamous suture; and
more rarely they have been found at the base, in the suture between the sphenoid
and ethmoid bones. Their size varies, in some cases not being larger than a pin's
head, and confined entirely to the outer table; in other cases so large, that a pair
of these bones formed the whole of that portion of the occipital bone above the
superior curved lines, as described by Beclard and others. Their number is
most generally limited to two or three; but more than a hundred have been found
in the skull of an adult hydrocephalic skeleton. It appears most probable that
they are separate accidental points of ossification, which, during their develop-
ment and growth, remain separate from the adjoining bones. In their development,
structure, and mode of articulation, they resemble the other cranial bones.
Bones of the Face.
The Facial Bones are fourteen in number, viz., the
Two Nasal, Two Palate,
Two Superior Maxillary, Two Inferior Turbinated,
Two Lachrymal, Vomer,
Two Malar, Inferior Maxillary.
Nasal Bones.
The Nasal Bones (figs. 35, 36) are two small oblong bones, varying in size and
form in difierent individuals; they are placed side by side at the middle and upper
part of the face, forming by their junction the bridge of the nose. Each bone
presents for examina-
tion two surfaces, and
four borders. The outer
surface is concave from
above downwards, con-
vex from side to side,
it is covered by the
Compressor nasi mus-
cle, marked by nu-
merous small arterial
furrows, and perforated
about its centre by a
OuteT Surface. foramen, sometimes
double, for the trans-
mission of a small vein. Sometimes this foramen is absent on one or both sides,
and occasionally the foramen coecum opens on this surface. The inner surface
* Wonnius, a physician in Copenhagen.
35. — Right Nasal Bone.
with F'rontal B.
/UfitJi
-Ojtposct& hone.
36.^Right Nasal Bone.
imth
FrontaZ lupine.-
crest
M-rpeiidicwlar
groove for iujisOjI nerve
Inner Surf (toe
40 OSTEOLOGY.
is concave from side to side, convex from above downwards; in which direction it
is traversed by a well marked longitudinal groove, sometimes a canal, for the
passage of a branch of the nasal nerve. The superior border is narrow, thick,
and serrated for articulation with the nasal notch of the frontal bone. The infe-
rior border is broad, thin, sharp, directed obliquely downwards, outwards and
backwards ; serving for the attachment of the lateral cartilage of the nose. This
border presents about its centre a notch, which transmits the branch of the nasal
nerve above referred to, and is prolonged at its inner extremity into a sharp
spine, which, when articulated with the opposite bone, forms the nasal angle. The
external border is serrated, bevelled at the expense of the internal surface above,
and of the external below, to articulate with the nasal process of the superior
maxillary. The internal border, thicker above than below, articulates with its
fellow of the opposite side, and is prolonged behind into a vertical crest, which
forms part of the septum of the nose; this crest articulates with the nasal spine
of the frontal above, and the perpendicular plate of the ethmoid below.
Development. By one centre for each bone, which appears about the same period
as in the vertebras.
Articulations. With four bones; two of the cranium, the frontal and ethmoid,
and two of the face, the opposite nasal and the superior maxillary.
No muscles are directly attached to this bone.
Superior Maxillary Bone.
The Superior Maxillary is one of the most important bones of the face in a
surgical point of view, on account of the number of diseases to which some of its
parts are liable. Its minute examination beccrmes, therefore, a matter of consi-
derable importance. It is the largest bone of the face, excepting the lower jaw,
and forms, by its union with its fellow of the opposite side, the whole of the up-
per jaw. Each bone assists in the formation of three cavities, the roof of the
mouth, the floor and outer wall of the nose, and the floor of the orbit; enters
into the formation of two fossae, the zygomatic and spheno-maxillary, and two
fissures, the spheno-maxillary, and pterygo-maxillary. Each bone presents for
examination a body and four processes, malar, nasal, alveolar, and palatine.
The body is somewhat quadrilateral, and is hollowed out in its interior to form
a large cavity, the antrum of Highmore. It presents for examination four sur-
faces, an external or facial, a posterior or zygomatic, a superior or orbital, and an
internal.
The external or facial surface (fig. 37) is directed forwards and outwards. In
the median line of the bone, just above the incisor teeth, is a depression, the incisive
or myrtiform fossa, which gives origin to the Depressor labii superioris alaeque nasi.
Above and a little external to it, the Compressor naris arises. More external and
immediately beneath the orbit, is another depression, the canine fossa, larger and
deeper than the incisive fossa, from which it is separated by a vertical ridge, the
canine eminence, corresponding to the socket of the canine tooth. The canine
fossa gives origin to the Levator anguli oris. Above the canine fossa is the infra
orbital foramen, the termination of the infra-orbital canal; it transmits the infra-
orbital nerve and artery. Above the infra-orbital foramen is the margin of the
orbit, which afibrds partial attachment to the Levator labii superioris proprius
muscle.
The posterior or zygomatic surface is convex, directed backwards and outwards,
and forms part of the zygomatic fossa. It presents about its centre two or three
grooves leading to canals in the substance of the bone; they are termed the poste-
rior dental canals, and transmit the posterior dental vessels and nerves. At
the lower part of this surface is a rounded eminence, the maxillary tuberosity,
especially prominent after the growth of the wisdom-tooth, rough on its inner side
for articulation with the tuberosity of the palate bone. At the upper and inner
part of this surface is the commencement of a groove, which, running down on the
SUPERIOR MAXILLARY BONE.
41
nasal surface of the bone, is converted into a canal by articulation with the palate
bone, forming the posterior palatine canal.
The superior or orbital surface is thin, smooth, irregularly quadrilateral, and
forms part of the floor of the orbit. It is bounded internally by an irregular
margin which articulates with three bones; in front, with the lachrymal; in the
middle, with the os planum of the ethmoid; and behind, with the orbital process
of the palate bone; posteriorly, by a smooth rounded edge which enters into the
formation of the spheno-maxillary fissure, and which sometimes articulates at its
anterior extremity with the orbital plate of the sphenoid; bounded externally b^
37. — Left Superior Maxillary Bone. Outer Surface.
Outer Surface .
Jncisive fossczr
Posterior Dental' Canals
Maxillary Tuterositu.
■*^**^''^-^Sji}5^
the malar process, and in front by part of the circumference of the orbit continuous,
on the inner side, with the nasal, on the outer side, with the malar process. Along
the middle line of this surface is a deep groove, the infra-orbital, for the passage of
the infra-orbital nerve and artery. This groove commences at the middle of the
posterior border of the bone, and, passing forwards, terminates in a canal which
subdivides into two branches; one of the canals, the infra-orbital, opens just below
the margin of the orbit; the other, the smaller and most posterior one, runs in the
substance of the anterior wall of the antrum; it is called the anterior dental, trans-
mitting the anterior dental vessels and nerves to the front teeth of the upper jaw.
The internal surface (fig. 38) is unequally divided into two parts by a hori-
zontal projection of bone, the palatine process; that portion above the palate-pro-
cess forms part of the outer wall of the nose; the portion below it forms part of
the cavity of the mouth. The superior division of this surface presents a large
irregular shaped opening leading into the antrum of Highmore. At the upper
border of this aperture are a number of broken cellular cavities, which, in the ar-
ticulated skull, are closed in by the ethmoid and lachrymal bones. Below the
aperture, is a smooth concavity which forms part of the inferior meatus of the nose,
traversed by a fissure, the maxillary fissure, which runs from the lower part of the
orifice of the antrum obliquely downwards and forwards, and receives the maxillary
process of the palate. Behind it, is a rough surface which articulates with the
perpendicular plate of the palate bone, traversed by a groove which, com-
42
OSTEOLOGY.
mencing near the middle of the posterior border, runs obliquely downwards and
forwards, and forms, when completed by its articulation with the palate bone, the
posterior palatine canal. In front of the opening in the antrum is a deep groove,
converted into a canal by the lachrymal and inferior turbinated bones, and lodging
the nasal duct. More anteriorly is a well marked rough ridge, the inferior turbi-
nated crest, for articulation with the inferior turbinated bone. The concavity
above this ridge forms part of the middle meatus of the nose, whilst that below it
forms part of the inferior meatus. The inferior division of this surface is concave,
rough and uneven, and perforated by numerous small foramina for the passage of
nutrient vessels.
38. — Left Superior Maxillary Bone. Inner Surface.
jSo77bj -pafttcully closivq Or^rfoce of ^'/vtT-aTn
Ethyrujid
J-nfcrior TurhiTiatecl
faZoute
Ant. NaswZ SfpLTta
J3ristle
pa^iscd nhrough
ATCt^poiliit. Canal
The Antrum of Highmore, or Maxillary Sinus, is a large triangular- shaped
cavity, hollowed out of the body of the maxillary bone; its apex, directed out-
wards, is formed by the malar process; its base, by the outer wall of the nose.
Its walls are everywhere exceedingly thin, its roof being formed by the orbital
plate, its floor by the alveolar process, bounded in front by the facial surface, and
behind by the zygomatic. Its inner wall, or base, presents, in the disarticulated
bone, a large irregular aperture, which communicates with the nasal fosste. The
margins of this aperture are thin and ragged, and the aperture itself is much con-
tracted by its articulation with the ethmoid above, the inferior turbinated below,
and the palate bone behind. In the articulated skull, this cavity communicates
with the middle meatus of the nose generally by two small apertures left between
the above-mentioned bones. In the recent state, usually only one small opening
exists, near the upper part of the cavity, sufficiently large to admit the end of a
probe, the rest being filled in by the lining membrane of the sinus.
Crossing the cavity of the antrum are often seen several projecting laminse of
bone, similar to those seen in the sinuses of the cranium; and on its outer wall are
the posterior dental canals, transmitting the posterior dental vessels and nerves to
the teeth. Projecting into the floor are several conical processes, corresponding to
the roots of the first and second molar teeth; in some cases, the floor is even per-
forated by the teeth in this situation. It is from the extreme thinness of the walls
of this cavity, that we are enabled to explain how tumours, growing from the
SUPERIOR MAXILLARY BONE.
43
antrum, encroach upon the adjacent parts, pushing up the floor of the orbit and
displacing the eyeball, projecting inward into the nose, protruding forwards on to
the cheek, and making their way backwards into the zygomatic fossa, and down-
wards into the mouth.
The Malar Process is a rough triangular eminence, situated at the angle of
separation of the facial from the zygomatic surface. In front, it is concave,
forming part of the facial surface; behind, it is also concave, and forms part of the
zygomatic fossa; superiorly, it is rough and serrated for articulation with the
malar bone; whilst below, a prominent ridge, marks the division between the
facial and zygomatic surfaces.
The Nasal Process is a thick triangular plate of bone, which projects upwards,
inwards, and backwards, by the side of the nose, forming its lateral boundary. Its
external surface is concave, smooth, perforated by numerous foramina, and gives
attachment to the Levator labii superioris algeque nasi, the Orbicularis palpebrarum,
and Tendo oculi. Its internal surface forms part of the inner wall of the nares;
it articulates above with the frontal, and presents a rough uneven surface which
articulates with the ethmoid bone, closing in the anterior ethmoid cells; below this
is a transverse ridge, the superior turbinated crest, for articulation with the middle
turbinated bone of the ethmoid, bounded below by a smooth concavity, which forms
part of the middle meatus; below this is the inferior turbinated crest (already de-
scribed), for articulation with the inferior turbinated bone ; and still more inferiorly,
the concavity which forms part of the inferior meatus. The anterior border of the
nasal process is thin, and serrated for articulation with the nasal bone: its poste-
rior border thick, and hollowed into a groove for the nasal duct; of the two margins
of this groove, the inner one articulates with the lachrymal bone, the outer one
forming part of the circumference of the orbit. Just where this border joins the
orbital surface is a small tubercle, the lachrymal tubercle. This serves as a guide
to the surgeon in the performance of the operation for fistula lachrymalis. The
lachrymal groove in the articulated skull is converted into a canal by the lachrymal
bone, and lachrymal process of the inferior turbinated; it is directed downwards,
and a little backwards and outwards, is about the diameter of a goose-quill, slightly
narrower in the middle than at either extremity, and lodges the nasal duct.
The Alveolar Process is the thickest part of the bone, broader behind than in
front, and excavated into deep cavities for the reception of the teeth. These
cavities are eight in number, and vary in size and depth according to the teeth
they contain: those for the canine teeth being the deepest; those for the molars
being widest, and subdivided into minor cavities ; those for the incisors being single,
but deep and narrow.
The Palate Process, thick and strong, projects horizontally inwards from the
inner surface of the bone. It is much thicker in front than behind, and forms the
floor of the nares, and the roof of the mouth. Its upper surface is concave from
side to side, smooth, and forms part of the floor of the nose. In front is seen the
upper orifice of the anterior palatine (incisor) canal, which leads into a fossa
formed by the junction of the two superior maxillary bones, and situated imme-
diately behind the incisor teeth. It transmits the anterior palatine vessels, the
naso-palatine nerves passing through the inter-maxillary suture. The inferior
surface, also concave, is rough and uneven, and forms part of the roof of the
mouth. This surface is perforated by numerous foramina for the passage of
nutritious vessels, channelled at the back part of its aveolar border by a longi-
tudinal groove, sometimes a canal, for the transmission of the posterior palatine
vessels, and a large nerve, and presents little depressions for the lodgment of the pala-
tine glands. This surface presents anteriorly the lower orifice of the anterior pala-
tine fossa. The outer border is firmly united with the rest of the bone. The inner
border is thicker in front than behind, raised above into a ridge, which, with
the corresponding ridge in the opposite bone, forms a groove for the reception of
the vomer. The anterior margin is bounded by the thin concave border of the
opening of the nose, prolonged forwards internally into a sharp process, forming,
44
OSTEOLOGY,
with a similar process of the opposite bone, the anterior nasal spine. The pos-
terior border is serrated for articulation with the horizontal plate of the palate
bone.
Development (fig. 39). This bone is formed at such an early period, and ossifi-
cation proceeds in it with such rapidity, that it has been found impracticable
^ , .PC. • TVT -n -D hitherto to determine with accu-
35_ — Development of Superior Maxillary Bone
By Four Centres.
J for N'asal ^
Facial portV,
i for Orlital, ^
Malar jiorfV
Anterior /Surface.
1 J^urU-n,
noriV:
1 -for Palatal jiorf—
racy its number of centres. It
appears, however, probable that
it has four centres of develop-
ment, viz., one for the nasal and
facial portions, one for the orbital
and malar, one for the incisive,
and one for the palatal portion, in-
cluding the entire palate except
the incisive segment. The inci-
sive portion is indicated in young
bones by a fissure, which marks
at off a small segment of the palate,
BlrtJi including the two incisor teeth.
In some animals, this remains
permanently as a separate piece,
constituting the intermaxillary
bone; and in the human subject,
where the jaw is malformed,
a detached piece is often found
in this situation, most probably
depending upon arrest of de-
velopment of this centre. The
maxillary sinus appears at an
earlier period than any of the other sinuses, its development commencing about the
fourth month of foetal life.
Articulations. With nine bones; two of the cranium — the frontal and ethmoid,
and with seven of the face, viz., the nasal, malar, lachrymal, inferior turbinated,
palate, vomer, and its fellow of the opposite side. Sometimes it articulates with
the orbital plate of the sphenoid.
Attachment of Muscles. Orbicularis palpebrarum, Obliquus inferior oculi. Leva-
tor labii superioris al^que nasi. Levator labii superioris proprius. Levator anguli-
oris, Compressor naris. Depressor al^e nasi, Masseter, Buccinator.
The Lachrymal Bones.
The Lachrymal are the smallest and most fragile of all the bones of the face,
situated at the front part of the inner wall of the
orbit, and resemble somewhat in form, thinness,
and size, a finger-nail; hence they are termed the
ossa unguis. Each bone presents for examination,
two surfaces and four borders. The external
(fig. 40) or orbital surface is divided by a vertical
ridge into two parts. The portion of bone in front
of this ridge presents a smooth, concave, longitu-
dinal groove, the free margin of which unites with
the nasal process of the superior maxillary bone,
completing the lachrymal groove. The upper part
of this groove lodges the lachrymal sac; the lower
part is continuous with the lachrymal canal, and
lodges the nasal duct. The portion of bone be-
hind the ridge is smooth, slightly concave, and
forms part of the inner wall of the orbit. The
40.-
-Left Lachrymal Bone.
External Surface.
vnA Frontal
Infi
( SligJiily
enla-rgcd \
MALAR BONE.
45
41. — Left Malar Bone. Outer Surface.
ridge, and part of the orbital surface immediately behind it, affords attachment
to the Tensor tarsi: it terminates below in a small hook-like process, which articu-
lates with the lachrymal tubercle of the superior maxillaiy bone, and completes
the upper orifice of the lachrymal canal. It sometimes exists as a separate piece,
which is then called the lesser lachrymal bone. The internal or nasal surface
presents a depressed furrow, corresponding to the elevated ridge on its outer
surface. The surface of bone in front of this forms part of the middle meatus;
and that behind it articulates with the ethmoid bone, filling in the anterior
ethmoidal cells. Of the four borders, the anterior is the longest, and articulates
with the nasal process of the superior maxillary bone. The posterior, thin and
uneven, articulates with the os planum of the ethmoid. The superior border, the
shortest and thickest, articulates with the internal angular process of the frontal
bone. The inferior is divided by the lower edge of the vertical crest into two
parts, the posterior articulating with the orbital plate of the superior maxillary
bone; the anterior portion being prolonged downwards into a pointed process,
which articulates with the lachrymal process of the inferior turbinated bone,
assisting in the formation of the lachrymal canal.
Development. By a single centre, which makes its appearance soon after ossi-
fication of the vertebrse has commenced.
Articulations. With four bones; two of the cranium, the frontal and ethmoid,
and two of the face, the superior maxillary and the inferior turbinated.
Attachment of Muscles. The Tensor tarsi.
The Malar Bones.
The Malar are two small quadrangular bones, situated at the upper and outer
part of the face, forming the prominence of the cheek, part of the outer wall and floor
of the orbit, and part of the tem-
poral and zygomatic fossae. Each
bone presents for examination an
external and an internal surface ;
four processes, the frontal, orbital,
maxillary, and zygomatic; and
four borders. The external sur-
face (fig. 41) is smooth, convex,
perforated near its centre by one
or two small apertures, the malar
canals, for the passage of small
nerves and vessels, covered by
the Orbicularis palpebrarum mus-
cle, and affords attachment to the
Zygomaticus major and minor
muscles.
The internal surface (fig. 42),
directed backwards and inwards,
is concave, presenting internally
a rough triangular surface, for articulation with the superior maxillary bone; and
externally, a smooth concave surface, which forms the anterior boundary of the tem-
poral fossa above, wider below, where it forms part of the zygomatic fossa. This
surface presents a little above its centre the aperture of one or two malar canals, and
affords attachment to part of two muscles, the temporal above, and the masseter below.
Of the four processes, the frontal is thick and serrated, and articulates with the
external angular process of the frontal bone. The orbital process is a thick and
strong plate, which projects backwards from the orbital margin of the bone. Its
upper surface, smooth and concave, forms, by its junction with the great ala of
the sphenoid, the outer wall of the orbit. Its under surface, smooth and convex,
forms part of the temporal fossa. Its anterior margin is smooth and rounded,
forming part of the circumference of the orbit. Its superior margin, rough, and
Tcrrtporo M.ala.r Cancels
46
OSTEOLOGY.
42. — Left Malar Bone. Inner Surface.
directed horizontally, articulates with the frontal behind the external angular
process. Its posterior margin is rough and serrated, for articulation with the
sphenoid; internally it is also serrated for articulation with the orbital process of
the superior maxillary. At the angle of junction of the sphenoid and maxillary
portions, a short rounded non-articular margin is sometimes seen; this forms the
anterior boundary of the spheno-
maxillary fissure: occasionally,
no such non-articular surface
exists, the fissure being completed
by the direct junction of the
maxillary and sphenoid bones,
or by the interposition of a small
Wormian bone in the angular
interval between them.
On the upper surface of the
orbital process are seen the ori-
fices of one or two malar canals;
one of these usually opens on the
posterior surface, the other (occa-
sionally two), on the facial sur-
face: they transmit filaments
of the orbital branch of the supe-
rior maxillary nerve. The rnax-
illary process is a rough trian-
gular surface, which articulates with the superior maxillary bone. The zygomatic
process, long, narrow, and serrated, articulates with the zygomatic process of the
temporal bone. Of the four borders, the superior, or orbital, is smooth, arched,
and forms a considerable part of the circumference of the orbit. The inferior, or
zygomatic, is continuous with the lower border of the zygomatic arch, affording
attachment by its rough edge to the Masseter muscle. The anterior or maxillary
border is rough, and bevelled at the expense of its inner table, to articulate with
the superior maxillary bone; affording attachment by its outer margin to the
levator labii superioris proprius, just at its point of junction with the superior
maxillary. The posterior or temporal border, curved like an italic f, is con-
tinuous above with the commencement of the temporal ridge; below, with the
upper border of the zygomatic arch; it afibrds attachment to the temporal fascia.
Development. By a single centre of ossification, which appears at about the same
period when ossification of the vertebra commences.
Articulations. With four bones: three of the cranium, frontal, sphenoid, and
temporal; and one of the face, the superior maxillary.
Attachment of Muscles. Levator labii superioris proprius, Zygomaticus major
and minor, Masseter, and Temporal.
The Palate Bones.
The Palate Bones are situated at the posterior part of the nasal fossas, wedged in
between the superior maxillary and the pterygoid process of the sphenoid. In form
they are somewhat like the letter L. Each bone assists in the formation of three cavi-
ties ; the floor and outer wall of the nose, the roof of the mouth, and the floor of
the orbit; and enters into the formation of three fossa;; the zygomatic, spheno-
maxillary, and pterygoid. Each bone consists of two portions; an inferior or
horizontal plate, a superior or vertical plate.
The Horizontal Plate is thick, of a quadrilateral form, and presents two sur-
faces and four borders. The superior surface, concave from side to side, forms
the back part of the floor of the nares. The inferior surface, slightly concave and
rough, forms the back part of the hard palate. At its posterior part may be seen
a transverse ridge, more or less marked, for the attachment of the tendon of the
Tensor palati muscle. At the outer extremity of this ridge is a deep groove, con-
PALATE BONE.
47
verted into a canal by its articulation with the tuberosity of the superior maxil-
lary bone, and forming the posterior palatine canal. Near this groove, the orifices
of one or two small canals, accessory posterior palatine, may frequently be seen.
The anterior border is serrated, bevelled at the expense of its inferior surface, and
articulates with the palate process of the superior maxillary bone. The posterior
border is concave, free, and serves for the attachment of the soft palate. Its
inner extremity is sharp and pointed, and when united with the opposite bone,
forms a projecting process, the posterior nasal spine, for the attachment of the
Azygos uvulae. The external border is united with the lower part of the perpen-
dicular plate almost at right angles. The internal border, the thickest, is serrated
for articulation with its fellow of the opposite side; its superior edge is raised
into a ridge, which, united with the opposite bone, forms a groove, in which the
vomer is received.
43) is thin, of an oblong form, and directed upwards
Left Palate Bone. Internal View (enlarged).
43--
^viicol I'to,
SfU
Superior ^fcatu,s.
The Vertical Plate (fig.
and a little inwards. It
presents two surfaces, an
external and an internal,
and four borders.
The internal surface pre-
sents at its lower part a
broad shallow depression,
which forms part of the
lateral boundary of the in-
ferior meatus. Immediately
above this is a well marked
horizontal ridge, the infe-
rior turbinated crest, for
the articulation of the in-
ferior turbinated bone ;
above this, a second broad
shallow depression may
be seen, which forms part
of the lateral boundary of
the middle meatus, sur-
mounted above by a hori-
zontal ridge, less prominent
than the inferior, the superior turbinated crest, for the articulation of the middle
turbinated bone. Above the superior turbinated crest is a narrow horizontal
groove, which forms part of the superior meatus. The external surface is rough
and irregular throughout the greater part of its extent, for articulation with the
inner surface of the superior maxillary bone, its upper and back part being smooth
where it enters into the formation of the zygomatic fossa; it is also smooth in
front, where it covers the orifice of the antrum. This surface presents towards
its back part a deep groove, converted into a canal, the posterior palatine, by its
articulation with the superior maxillary bone. It transmits the posterior pala-
tine vessels and a large nerve. The anterior border is thin, irregular, and presents
opposite the inferior turbinated crest, a pointed projecting lamina, the maxillary
process of the palate bone, which is directed forwards, and closes in the lower
and back part of the opening of the antrum, being received into a fissure that
exists at the inferior part of this aperture. The posterior border (fig. 44) presents
a deep groove, the edges of which are serrated for articulation with the ptery-
goid process of the sphenoid. At the lower part of this border is seen a pyramidal
process of bone, the pterygoid process or tuberosity of the palate, which is
received into the angular interval between the two pterygoid plates of the
sphenoid at their inferior extremity. This process presents at its back part
three grooves, a median and two lateral ones. The former is smooth, and forms
part of the pterygoid fossa, aflfording attachment to the Internal pterygoid muscle;
HORIZONTAL PLATE
48
OSTEOLOGY.
S/ihcTiot^lal firocc&s.
i/rticular hort.
on. articuUi/rho rL *
whilst the lateral grooves are rough and uneven, for articulation with the anterior
border of each pterygoid plate. The base of this process, continuous with the
horizontal portion of the bone, presents the apertures of the accessory descending
palatine canals; whilst its outer surface is rough, for articulation with the inner
surface of the body of the superior maxillary bone. The superior border of the
vertical plate presents two well Left Palate Bone. Posterior View (enlarged),
marked processes, separated by
an intervening notch or foramen.
The anterior, or larger,is called the
orbital process; the posterior, the
sphenoidal. The Orbital Process,
directed upwards and outwards,
is placed on a higher level than
the sphenoidal. It presents five
surfaces, which enclose a hollow
cellular cavity, and is connected
to the perpendicular plate by a
narrow constricted neck. Of
these five surfaces, three are
articular, two non-articular, or
free surfaces. The three articu-
lar are the anterior or maxillary
surface, which is directed for-
wards, outwards, and downwards,
is of an oblong form, and rough
for articulation with the superior
maxillary bone. The posterior
or sphenoidal surface, is directed
backwards, upwards, and inwards. It ordinarily presents a small half-cellular
cavity which communicates with the sphenoidal sinus, and the margins of which
are serrated for articulation with the vertical part of the sphenoidal turbinated bone.
The internal or ethmoidal surface is directed inwards, upwards and forwards,
and articulates with the lateral mass of the ethmoid bone. In some cases, the
cellular cavity above-mentioned opens on this surface of the bone, it then commu-
nicates with the posterior ethmoidal cells. More rarely it opens on both surfaces,
and then communicates with the posterior ethmoidal cells, and the sphenoidal
sinus. The non-articular or free surfaces of the orbital process are the superior
or orbital, directed upwards and outwards, of a triangular form, concave, smooth,
articulating with the superior maxillary bone, and forming the back part of the
floor of the orbit. The external or zygomatic surface, directed outwards, back-
wards and downwards, is of an oblong form, smooth, and forms part , of the
zygomatic fossa. This surface is separated from the orbital by a smooth rounded
border, which enters into the formation of the spheno-maxillary fissure.
The Sphenoidal Process of the palate bone is a thin compressed plate, much
smaller than the orbital, and directed upwards and inwards. It presents three
surfaces and two borders. The superior surface, the smallest of the three, articu-
lates with the horizontal part of the sphenoidal turbinated bone; it presents a
groove which contributes to the formation of the pterygo-palatine canal. The
internal surface is concave, and forms part of the outer wall of the nasal fossa.
The external surface is divided into two parts, an articular, and a non-articular
portion; the non-articular portion is smooth and free, forming part of the zygo-
matic fossa, whilst behind is a rough surface for articulation with the inner surface
of the pterygoid process of the sphenoid. The anterior border forms the posterior
boundary of the spheno-palatine foramen. The posterior border, serrated at the
expense of the outer table, articulates with the internal surface of the pterygoid
process.
The orbital and sphenoidal processes are separated from one another by a deep
INFERIOR TURBINATED BONE.
49
notch, which is converted into a foramen, the spheno-palatine, by articulation with
tlie sphenoidal turbinated bone. Sometimes the two processes are united above,
and form between them a complete foramen, or the notch is crossed by one or
more spiculas of bone, so as to form two or more foramina. In the articulated
skull, this foramen opens into the back part of the outer wall of the superior
meatus, and transmits the spheno-palatine vessels and nerves.
Development. From a single centre, which makes its appearance at the angle of
junction of the two plates of the bone. From this point ossification spreads; in-
wards, to the horizontal plate; downwards, into the tuberosity; and upwards, into
the vertical plate. In the foetus, the horizontal plate is much longer than the
vertical; and even after it is fully ossified, the whole bone is remarkable for its
shortness.
Articulations. With seven bones; the sphenoid, ethmoid, superior maxillary,
inferior turbinated, vomer, opposite palate, and sphenoidal turbinated.
Attachment of Muscles. The Tensor palati, Azygos uvulee, Internal and External
pterygoid.
The Inferior Turbinated Bones.
The Inferior Turbinated bones are situated one on each side of the outer wall
of the nasal fossae. Each bone consists of a layer of thin ' spongy ' bone, curled upon
itself like a scroll, hence its name 'turbinated;' and extending horizontally across
the outer wall df the nasal fossa, immediately below the orifice of the antrum.
Each bone pi-esents two surfaces, two borders, and two extremities.
The internal surface (fig. 45) is convex, perforated by numerous apertures, and
traversed by longitudinal grooves
45--
-Eight Inferior Turbinated Bone.
Inner Surface.
and canals for the lodgment of
arteries and veins. In the recent
state it is covered by the lining
membrane of the nose. The exter-
nal surface is concave (fig. 46), and
forms part of the inferior meatus.
Its upper border is thin, irregular,
and connected to various bones
along the outer wall of the nose.
It may be divided into three por-
tions; of these, the anterior articu-
lates .with the inferior turbinated
crest of the superior maxillary bone; the posterior with the inferior turbinated
crest of the palate bone; the middle portion of the superior border presents three
well marked processes, which vary much -r,.,,T^- mi- ,1-r,
,1 . . J p ^p ,1 •' ^1 4.6. — Rigrnt Intenor Turbmated Bone,
m their size and form. Of these the ^ * Outer Surface
anterior and smallest, is situated at the
junction of the anterior fourth with the
posterior three-fourths of the bone; it is
small and pointed, and is called the la-
chrymal process, for it articulates with the
anterior inferior angle of the lachrymal
bone, and by its margins, with the groove
on the back of the nasal process of the su-
perior maxillary, and thus assists in forming the lachrymal canal,
of the two middle fourths of the bone, but encroaching on the latter, a broad thin
plate, the ethmoidal process, ascends to join the unciform process of the ethmoid;
from the lower border of this process, a thin lamina of bone curves downwards
and outwards, hooking over the lower edge of the orifice of the antrum, which
it narrows below; it is called the maxillary process^, and fixes the bone firmly on
to the outer wall of the nasal fossa. The inferior border is Tree, thick and cellular
in structure, more especially in the centre of the bone. Both extremities are
£
At the junction
so
OSTEOLOGY.
more or less narrow and pointed. If the bone is held so that its outer concave
surface is directed backwards (i.e., towards the holder), and its superior border,
from which the lachrymal and ethmoidal processes project, upwards, the lachrymal
process will be directed to the side to which the bone belongs.
Developments By a single centre which makes its appearance about the middle
of foetal life.
Artictilations. With four bones; one of the cranium, the ethmoid, and three of
the face, the superior maxillary, lachrymal and palate.
No muscles ai-e attached to this bone.
The Vomer.
The Vomer (fig. 47.) is a single bone, situated vertically at the back part of the
nasal fossas, and forming part of the septum of the nose. It is thin, somewhat
like a ploughshare in form, but it varies in different individuals, being frequently
bent to one or the other side; „
it presents for examination
two surfaces and four borders.
The lateral surfaces are
smooth, marked with small
furrows for the lodgment of
blood-vessels, and by a groove
on each side, sometimes a
canal, the naso-palatine, which
runs obliquely downwards and
forwards to the intermaxillary
suture between the two ante-
rior palatine canals; it trans-
mits the naso-palatine nerve.
The superior border, the thick-
est, presents a deep groove, bounded on each side by a horizontal projecting ala of
bone; the groove receives the rostrum of the sphenoid, whilst the alte are over-
lapped and retained by laminae which project from the under surface of the body of
the sphenoid at the base of the pterygoid processes. At the anterior part of the
groove a fissure is left for the transmission of blood-vessels to the substance of the
bone. The inferior border, the longest, is broad and uneven in front, where it arti-
culates with the two superior maxillary bones; thin and sharp behind where it
joins with the palate bones. The upper half of the anterior border usually pre- ;
sents two laminae of bone, which receive between them the perpendicular plate of i|
the ethmoid, the lower half consisting of a single rough edge, also occasionally
channelled, which is united to the triangular cartilage of the nose. The posterior
border is free, concave, and separates the nasal fossEe from one another behind.
It is thick and bifid above, thin below.
Development. The vomer at an early period consists of two laming united below, ^
but separated above by a very considerable interval. Ossification commences in
it at about the same period as in the vertebrae.
Articulations. With six bones; two of the cranium, the sphenoid and ethmoid;
and four of the face, the two superior maxillary, the two palate bones, and with
the cartilage of the septum.
The vomer has no muscles attached to it.
The Inferior Maxillary Bone.
The Inferior Maxillary Bone, the largest and strongest bone of the face, serves
for the reception of the inferior teeth. It consists of a curved horizontal portion,
the body, and of two perpendicular portions, the rami, which join the former nearly
at right angles behind.
The Horizontal portion, or body (fig. 48), is convex in its general outline, and
curved somewhat like a horse-shoe. It presents for examination two surfaces
'"'^'^^ Swp .MoiXfiH. 1°
INFERIOR MAXILLARY BONE.
51
and two borders. The External Surface is convex from side to side, concave from
above downwards. In the median line is a well marked vertical ridge, the sym-
physis; it extends from the upper to the lower border of the bone, and indicates
48. — Inferior Maxillary Bone. Outer Surface. Side View.
Me-niffJ/
firocesa
Groove ^ofjt
the point of junction of the two pieces of which the bone is composed at an early
period of life. The lower part of the ridge terminates in a prominent triangular
eminence, the mental process. On either side of the symphysis, just below the
roots of the incisor teeth, is a depression, the incisive fossa, for the attachment of
the Levator menti; and still more externally, a foramen, the mental foramen, for
the passage of the mental nerve and artery. This foramen is placed just below
the root of the second bicuspid tooth. Running outwards from the base of the
mental process on each side, is a well marked ridge, the external oblique line.
This ridge is at first nearly horizontal, but afterwards inclines upwards and back-
wards, and is continuous with the anterior border of the ramus; it affords attach-
ment to the Depressor labii inferioris and Depressor anguli oris, below it, to the
Platysma myoides.
The Internal Surface (fig. 49) is concave from side to side, convex from above
downwards. In the middle line is an indistinct linear depression, corresponding to
the symphysis externally; on either side of this depression, just below its centre,
are four prominent tubercles, placed in pairs, two above and two below; they are
called the genial tubercles, and afford attachment, the upper pair to the Genio-hyo-
glossi muscles, the lower pair to the Genio-hyodei muscles. Sometimes the
tubercles on each side are blended into one, or they all unite into an irregular
eminence of bone, or nothing but an irregularity may be seen on the surface of
the bone at this part. On either side of the genial tubercles is an oval depression,
the sublingual fossa, for lodging the sublingual gland; and beneath it a rough
depression on each side, which gives attachment to the anterior belly of the Digas-
tric muscle. At the back part of the sublingual fossa, the internal oblique line
(mylo-hyoidean) commences; it is faintly marked at its commencement, but becomes
more distinct as it passes upwards and outwards, and is especially prominent
opposite the two last molar teeth; it divides the lateral surface of the bone into
two portions, and affords attachment throughout its whole extent to the Mylo-hyoid
muscle, the Superior constrictor being attached above its posterior extremity,
nearer the alveolar margin. The portion of bone above this ridge is smooth, and
covered by the mucous membrane of the mouth; whilst that below it presents an
E 2
52
OSTEOLOGY.
oblong depression, wider behind than in front, the submaxillary fossa, for the lodg-
ment of the submaxillary gland. The superior or alveolar border is wider, and its
margins thicker behind than in front. It is hollowed into numerous cavities, for the
49. — Inferior Maxillary Bone. Inner Surface. Side View.
.>tK '^"'^J^.
GENIO-HYO-GLOSSUS
CENIO-HYOIDEUS
Mylo-Tiyoicl Eidje
Bod
reception of the teeth; these are sixteen in number, and vary in depth and size accord-
ing to the teeth which they contain. At an early period of life, before the eruption
of the teeth, the alveolar process is proportionally larger and deeper than in the adult,
and the chief part of the body is above the oblique line. In adult life the base of
the bone attains its maximum of development. In old age, on the contrary, after
the loss of the teeth, the alveolar process becomes absorbed, and the chief part
of the body is that which exists below the obliqvie line. At this period, the dental
canal and mental foramen are situated close to the upper border of the bone. The
inferior border, longer than the superior, and thicker in front than behind, is rounded;
it presents a shallow groove, just where the body joins the ramus, over which the
facial artery turns.
The Perpendicular Portions, or Rami, are of a quadrilateral form, and differ
in their direction at various periods of life. In the foetus, they are almost parallel
with the body; in youth they are oblique; in manhood they are nearly vertical,
joining the body at almost a right angle. In old age, after the loss of the teeth,
they again decline and assume an oblique direction. Each ramus presents for
examination two surfaces, four borders, and two processes. The external surface
is flat, marked with ridges, and gives attachment throughout nearly the whole of
its extent to the Masseter muscle. The internal surface presents about its centre
the oblique aperture of the inferior dental canal, for the passage of the inferior dental
vessels and nerve. The margins of this opening are irregular, and present in front
a prominent ridge, surmounted by a sharp spine, which gives attachment to the
internal lateral ligament of the lower jaw; and at its lower and back part is
seen a notch leading to a groove, which runs obliquely downwards to the pos-
terior extremity of the submaxillary fossa; this groove is the mylo-hyoidean, and
lodges the mylo-hyoid vessels and nerve; behind the groove is a rough surface,
for the insertion of the Internal pterygoid muscle. The inferior dental canal
descends obliquely downwards and forwards in the substance of the ramus, and
then horizontally forwards in the body; it is here placed under the alveoli, with
which it communicates by small openings. On arriving at the incisor teeth, it
SUTURES OF THE SKULL.
53
turns back to communicate with the mental foramen, giving off two Bmall canals,
which run forward, to be lost in the cancellous tissue of the bone beneath the in-
cisor teeth. This canal, in the posterior two-thirds of the bone, runs nearest the
internal surface of the jaw; and in the anterior third, nearer its external surface.
Its walls are composed of compact tissue at either extremity, cancellous in the centre.
It contains the inferior dental vessels and nerve, from which branches are distributed
to the teeth through the small apertures at the bases of the alveoli. The superior
border is thin, and presents two processes, separated by a deep concavity, the
sigmoid notch. Of these processes, the anterior is the coronoid, the posterior the
condyloid.
The Coronoid Process is a thin, flattened, triangular eminence of bone, which
varies in length in different subjects. Its external surface is smooth, and affords
attachment to the masseter and temporal muscles. Its interyial surface gives
attachment to the temporal muscle, and presents the commencement of a longitu-
dinal ridge, which is continued to the posterior part of the alveolar process. In
front of this ridge is a deep groove, continued below on to the outer side of the
alveolar process; this ridge and part of the groove afford attachment above to
the Temporal, below to the Buccinator muscle.
The Condyloid Process, shorter but thicker than the coronoid, consists of two
portions; the condyle, and the constricted portion which supports the condyle, the
neck. The condyle is of an oval form, its long axis being transverse, and placed
in such a manner that its outer end is a little more forward and a little higher
than its inner. It is convex from before backwards, and from side to side, the
articular surface extending further on the posterior than on the anterior surface.
The neck of the condyle is flattened from before backwards. Its posterior surface
is convex; its anterior is hollowed out on its inner side by a depression (the
pterygoid fossa), for the attachment of the External pterygoid. The lower border
of the ramus is thick, straight, and continuous with the body of the bone. At its
junction with the posterior border is the angle of the jaw, which is somewhat everted,
rough on each side for the attachment of the masseter externally, and the internal
pterygoid internally, and, between them, serving for the attachment of the stylo-
maxillary ligament. The anterior border is thin above, thicker below, and continu-
ous with the external oblique line. The posterior border is thick, smooth, and
rounded, and covered by the parotid gland.
The Sigmoid Notch, separating the two processes, is a deep semilunar depres-
sion, crossed by the masseteric artery and nerve.
Development. This bone is formed at such an early period of life, befoi'e, indeed,
any other bone excepting the clavicle, that it has been found impossible at present
to determine its earliest condition. It appears probable, however, that it is deve-
loped by two centres, one for each lateral half, the two segments meeting at the
symphysis, where they become united. Additional centres have also been described
for the coronoid process, the condyle, the angle, and the thin plate of bone, which
forms the inner side of the alveolus. At birth it consists of two lateral halves.
These join at the symphysis at the end of the first year; but a trace of separation
at their upper part is seen at the commencement of the second year.
Articulations. With the glenoid fossae of the two temporal bones.
Attachment of 3Iuscles. By its external surface, commencing at the symphysis,
and proceeding backwards; Levator menti, Depressor labii inferioris. Depressor
anguli oris, Platysma myoides, Buccinator, Masseter. By its internal surface, com-
mencing at the same point; Genio-hyo-glossus, Genio-hyoideus, Mylo-hyoideus,
Digastric, Superior constrictor. Temporal, Internal pterygoid. External pterygoid.
Articulations of the Cranial Bones.
The bones of the cranium and face, are connected to each other by means of
sutures. The Cranial Sutures may be divided into three sets: I. Those of the
vertex of the skull. 2. Those at the side of the skull. 3. Those at the base.
54 OSTEOLOGY.
The sutures at the vertex of the skull are three, the sagittal, coronal, and
lambdoid.
The Sagittal Suture {sagitta, an arrow) is formed by the junction of the two
parietal bones, and extends from the middle of the frontal bone, backwards to the
superior angle of the occipital. In childhood, and occasionally in the adult, when
the two halves of the frontal bone are not united, it is continued forwards to the
root of the nose. This suture sometimes presents, near its posterior extremity, the
parietal foramen on each side; and in front, where it joins the coronal suture, a
space is occasionally left, which encloses a large Wormian bone.
The Coronal Suture extends transversely across the vertex of the skull, and
connects the frontal with the parietal bones. It commences at the extremity of
the great wing of the sphenoid on one side, and terminates at the same point on
the opposite side. The dentations of this suture are more marked at the sides than
at the summit, and are so constructed that the frontal rests on the parietal above,
whilst laterally the parietal supports the frontal.
The Lambdoid Suture, so called from its resemblance to the Greek letter X,
connects the occipital with the parietal bones. It commences on each side at the
angle of the mastoid portion of the temporal bone, and inclines upwards to the end
of the sagittal suture. The dentations of this suture are very deep and distinct,
and are often interrupted by several small Wormian bones.
The sutures at the side of the skull are also three in number; the spheno-parietal,
squamo-parietal, and masto-parietal. They are subdivisions of a single suture,
formed between the lower border of the parietal, and the temporal and sphenoid
bones, and extending from the lower end of the lambdoid suture behind, to the lower
end of the coronal suture in front.
The Spheno-parietal is very short, and formed by the tip of the great wing of
the sphenoid, and the anterior inferior angle of the parietal bone.
The Squamo-parietal, or squamous suture, is arched. It is formed by the squa-
mous portion of the temporal bone overlapping the middle division of the lower
border of the parietal.
The Masto-parietal is a short suture, deeply dentated, formed by the posterior
inferior angle of the parietal, and the superior border of the mastoid portion of
the temporal.
The sutures at the base of the skull are the basilar in the centre, and on each
side, the petro-occipital, the masto-occipital, the petro-sphenoidal, and the squamo-
sphenoidal.
The Basilar Suture is formed by the junction of the basilar surface of the
occipital bone with the posterior surface of the body of the sphenoid. At an
early period of life a thin plate of cartilage exists between these bones, but in the
adult they become inseparably united. Between the outer extremity of the basilar
suture, and the termination of the lambdoid, an irregular suture exists which is
subdivided into two portions. The inner portion, formed by the union of the
petrous part of the temporal, with the occipital bone, is termed the petro-occipital.
The outer portion, formed by the junction of the mastoid part of the temporal with
the occipital, is called the masto-occipital. Between the bones forming the petro-
occipital suture, a thin plate of cartilage exists; in the masto-occipital is occa-
sionally found the opening of the mastoid foramen. Between the outer extremity
of the basilar suture and the spheno-parietal, an irregular suture may be seen
formed by the union of the sphenoid with the temporal bone. The inner and
smaller portion of this suture is termed the petro-sphenoidal; it is formed between
the petrous portion of the temporal, and the great wing of the sphenoid; the
outer portion, of greater length, and arched, is formed between the squamous por-
tion of the temporal and the great wing of the sphenoid, it is called the squamo-
sphenoidal.
The cranial bones are connected with those of the face, and the facial with each
other, by numerous sutures, which, though distinctly marked, have received no
special names. The only remaining suture deserving especial consideration is the
THE SKULL.
55
transverse. This extends across the upper part of the face, and is formed by the
junction of the frontal with the facial bones; it extends from the external angular
process of one side, to the same point on the opposite side, and connects the frontal
with the malar, the sphenoid, the ethmoid, the lachrymal, the superior maxillary,
and the nasal bones on each side.
The Skull.
The Skull, formed by the union of the several cranial and facial bones already
described, when considered as a whole, is divisible into five regions; a superior
region or vertex, an inferior region or base, two lateral regions, and an anterior
region, the face.
The Superior Region, or vertex, presents two surfaces, and external and an
internal. The External Surface is bounded in front by the nasal eminences, and
superciliary ridges; behind, by the occipital protuberance and superior curved lines
of the occipital bone, laterally, by an imaginary line extending from the outer end
of the superior curved line, along the temporal ridge, to the external angular pro-
cess of the frontal. This surface includes the vertical portion of the frontal, the
greater part of the parietal, and the superior third of the occipital bone; it is
smooth, convex, of an elongated oval form, crossed transversely by the coronal
suture, and from before backwards by the sagittal, which terminates behind in the
lambdoid. From before backwards may be seen the frontal eminences and remains
of the suture connecting the two lateral halves of the frontal bone ; on each side of
the sagittal suture is the parietal foramen and parietal eminence, and still more
posteriorly the smooth convex surface of the occipital bone.
The Internal Surface of the vertex is concave, presents eminences and de-
pressions for the convolutions of the brain, and numerous furrows for the lodgment
of branches of the meningeal arteries. Along the middle line of this surface is a
longitudinal groove, narrow in front, where it terminates in the frontal crest,
broader behind; it lodges the superior longitudinal sinus, and its mai-gins aiford
attachment to the falx cerebri. On either side of it are several depressions for the
Pacchionian bodies, and at its back part, the internal openings of the parietal
foramina. This surface is also crossed in front by the coronal suture; from before
backwards, by the sagittal; behind, by the lambdoid.
Base of the Skull.
The Inferior Region, or base of the skull presents two surfaces, an internal or
cerebral, and an external or basilar.
The Internal, or Cerebral Surface (fig. 50.), is divisible into three parts, or
fossje, called the anterior, middle, and posterior fossae of the cranium.
The Anterior Fossa is formed by the orbital plate of the frontal, the cribriform
plate of the ethmoid, the ethmoidal process and lesser wing of the sphenoid. It
is the most elevated of the three fossae, convex on each side where it corresponds
to the roof of the orbits, concave in the median line in the situation of the cribri-
form plate of the ethmoid. It is traversed by three sutures, the ethmoido-frontal,
ethmo- sphenoidal, and fronto- sphenoidal, and lodges the anterior lobes of the cere-
brum. It presents in the median line from before backwards, the commencement of
the groove for the superior longitudinal sinus, and crest for the attachment of the falx
cerebri; the foramen ccecum, this aperture is formed by the frontal and crista galli
of the ethmoid, and if pervious, transmits a small vein from the nose to the superior
longitudinal sinus. Behind the foramen coecum is the crista galli, the posterior
margin of which affords attachment to the falx cerebri. On either side of the
crista galli is the olfactory groove, which supports the bulb of the olfactory nerves,
perforated by the three sets of orifices which give passage to its filaments; and in
front by a slit-like opening, which transmits the nasal branch of the ophthalmic
nerve. On each side are the internal openings of the anterior and posterior
ethmoidal foramina, the former, situated about the middle of its outer margin,
transmitting the nasal nerve, which runs in a groove along its surface, to the slit-
56
OSTEOLOaY.
like opening above mentioned; whilst the latter, the posterior ethmoidal foramen,
opens at the back part of this margin under cover of a projecting lamina of the
50. — Base of Skull. Inner or Cerebral Surface.
Groove fir Shi-per. Zimgitud, Sinios
drooves for ATite^r. MoTiinyealA'!-
Toramev, C/ecitr/i,-
Critstn, GnMi
Slit for "N/ii.ial ru.riKi.
j^ntcrior JEckmohdaUui:
Ovifiees fop OlftwtoryneTfe
Poxtcrior Edimoidnl Fo'.
Olfaatory ffrootfcs^
O^tio Toravicn
Optic OTOove-
Oliiianj pvoot
AjiterwT ClcTwid prac:
Middle Cluioid -proc
Posterior Clinorid jprco.
Groove for ffih norve
Tor^ laeerum medium'
Orifice of Carotid Canal
Dcpres^wn for CctsjicrCan Ganiglvon
Meatus Auditor. Internus
Slit for Diora-Mater
Sup. Petrosal grooi^C'
For. laeerum, posterius
AiUcrior CondyToLd JTn 71
Aqueduct. Ve<stihtiJi
Pot^terior Cond'ifloid For.
Mastoid Far.
Post. 3fenin,g ea,l Grooifes,
sphenoid, it transmits the posterior ethmoidal artery and vein to the posterior
ethmoidal cells. Further back in the middle line is the ethmoidal spine, bounded
])ehind by an elevated ridge, separating a longitudinal groove on each side which
BASE OF THE SKULL.
■57
support the olfactory nerves. The anterior fossa presents laterally eminences and
depressions for the convolutions of the brain, and grooves for the lodgment of
the anterior meningeal arteries.
The Middle Fossa, somewhat deeper than the preceding, is narrow in the middle,
and becomes wider as it expands laterally. It is bounded in front by the poste-
rior margin of the lesser wing of the sphenoid, the anterior clinoid process, and the
anterior margin of the optic groove; behind, by the petrous portion of the temporal,
and basilar suture; externally, by the squamous portion of the temporal, and
anterior inferior angle of the parietal bone, and is divided into two lateral parts
by the sella Turcica. It is traversed by four sutures, the squamous, spheno-parietal,
spheno-temporal, and petro-sphenoidal.
In the middle line, from before backwards, is the optic groove, which supports
the optic commissure, terminating on each side in the optic foramen, for the
passage of the optic nerve and ophthalmic artery, behind is seen the olivary
process, and laterally the anterior clinoid processes, which afford attachment to
the folds of the dura mater, which form the cavernous sinus. In the centre of the middle
fossa is the sella Turcica, a deep depression, which lodges the pituitary gland,
bounded in front by a small eminence on either side, the middle clinoid process,
and behind by a broad square plate of bone, surmounted at each superior angle
by a tubercle, the posterior clinoid process; beneath the latter process is a groove,
for the lodgment of the sixth nerve. On each side of the sella Turcica is the
cavernous groove; it is broad, shallow, and curved somewhat like the italic letter
f; it commences behind at the foramen lacerum medium, and terminates on the
inner side of the anterior clinoid process. This groove lodges the cavernous sinus,
the internal carotid artery, and the orbital nerves. The sides of the middle fossa
are of considerable depth; they present eminences and depressions for the middle
lobes of the brain, and grooves for lodging the branches of the middle meningeal
artery'; these commence on the outer side of the foramen spinosum, and consist of
two large branches, an anterior rnd a posterior; the former passing upwards and
forwards to the anterior inferior angle of the parietal bone, the latter passing
upwards and backwards. The following foramina may also be seen from before
backwards. Most anteriorly is the foramen lacerum anterius, or sphenoidal fissure,
formed above by the lesser wing of the sphenoid; below, by the greater wing;
internally, by the body of the sphenoid; and completed externally by the orbital
plate of the frontal bone. It transmits the third, fourth, the three branches of
the ophthalmic division of the fifth, the sixth nerve, and the ophthalmic vein.
Behind the inner extremity of the sphenoidal fissure is the foramen rotundum, for
the passage of the second division of the fifth or superior maxillary nerve; still
more posteriorly is seen a small orifice, the foramen Vesalii; this opening is situ-
ated between the foramen rotundum and ovale, a little internal to both; it varies
in size in different individuals, and transmits a small vein. It opens below in
the pterygoid fossa, just at the outer side of the scaphoid depression. Poste-
riorly and externally is the foramen ovale, which transmits the third division of
the fifth or inferior maxillary nerve, the small meningeal artery, and the small
petrosal nerve. On the outer side of the foramen ovale is the foramen sjjinosum,
for the passage of the middle meningeal artery ; and on the inner side of the foramen
ovale, the foramen lacerum medium. This aperture in the recent state is filled up
with cartilage. On the anterior surface of the petrous portion of the temporal
bone is seen from without inwards, the eminence caused by the projection of the
superior semicircular canal, the groove leading to the hiatus Fallopii, for the
transmission of the petrosal branch of the Vidian nerve; beneath it, the smaller
groove, for the passage of the smaller petrosal nerve; and near the apex of the
bone, the depression for the semilunar ganglion, and the orifice of the carotid canal,
for the passage of the internal carotid artery and carotid plexus of nerves.
The Posterior Fossa, deeply concave, is the largest of the three, and situated
on a lower level than either of the preceding. It is formed by the occipital, the
petrous and mastoid portions of the temporal, and the posterior inferior angle of
58 OSTEOLOGY.
the parietal bones; is crossed by three sutures, the petro-occipital, masto-occipital,
and masto-parietal; and lodges the cerebellum, pons varolii, and medulla oblon-
gata. It is separated from the middle fossa in the median line by the basilar
suture, and on each side by the superior border of the petrous portion of the
temporal bone. This serves for the attachment of the tentorium cerebelli, is
grooved externally for the superior petrosal sinus, and at its inner extremity pre-
sents a notch, upon which rests the fifth nerve. Its circumference is bounded
posteriorly by the groove for the lateral sinus. In the centre of this fossa is
the foramen magnum, bounded on either side by a rough tubercle, which gives
attachment to the odontoid ligaments; and a little above these are seen the in-
ternal openings of the anterior condyloid foramina. In front of the foramen
magnum is the basilar process, grooved for the support of the medulla oblongata
and pons varolii, and articulating on each side with the petrous portion of the tem-
poral bone, forming the petro-occipital suture, the anterior half of which is grooved
for the inferior petrosal sinus, the posterior half being encroached upon by the
foramen lacerum posterius, or jugular foramen. This foramen is partially subdivided
into two parts; the posterior and larger division transmits the internal jugular
vein, the anterior the eighth pair of nerves. Above the jugular foramen is the
internal auditory foramen, for the auditory and facial nerves and auditory artery;
behind and external to this is the slit-like opening leading into the aquaeductus
vestibuli; whilst between these two latter, and near the superior border of the
petrous portion, is a small triangular depression, which lodges a process of the
dura mater, and occasionally transmits a small vein into the substance of the
bone. Behind the foramen magnum are the inferior occipital fossse, which lodge
the lateral lobes of the cerebellum, separated from one another by the internal
occipital crest, which serves for the attachment 'of the falx cerebelli, and lodges
the occijDital sinuses. These fosste are surmounted, above, by the deep transverse
grooves for the lodgment of the lateral sinuses, that on the right side being usually
larger than the left. These channels, in their passage outwards, groove the occi-
pital bone, the posterior inferior angle of the parietal, the mastoid portion of the
temporal, and the occipital just behind the jugular foramen, at the back part of
which they terminate. Where this sinus grooves the mastoid part of the temporal
bone, the orifice of the mastoid foramen may be seen; and just previous to its
termination it has opening into it the posterior condyloid foramen.
The External Surface of the base of the Skull (fig. 51) is extremely irregular.
It is bounded in front by the incisor teeth in the upper jaws; behind, by the
superior curved lines of the occipital bone; and laterally, by the lower border of
the malar bone, the zygomatic arch, and an imaginary line, extending from the
zygoma to the mastoid process and extremity of the superior curved line of the
occiput. It is formed by the palate processes of the two superior maxillary and
palate bones, the vomer, the pterygoid, under surface of the great wing, spinous
process and part of the body of the sphenoid, the under surface of the squamous,
mastoid, and petrous portions of the temporal, and occipital bones. The anterior
part of the base of the skull is raised above the level of the rest of this sur-
face (when the skull is turned over for the purpose of examination), surrounded
by the alveolar process, which is thicker behind than in front, and excavated by
sixteen depressions for lodging the teeth of the' upper jaw; they vary in depth and
size according to the teeth they contain. Immediately behind the incisor teeth is
the anterior palatine fossa or canal. At the bottom of this fossa may usually be
seen four apertures, two placed laterally, which open above, one in the floor of
each nostril, and transmit the anterior palatine vessels, and two in the median
line of the intermaxillary suture, one in front of the other, the most anterior one
transmitting the left, and the posterior one (the larger) the right naso-palatine
nerve. These two latter canals are sometimes wanting, or they may join to form
a single one, or one of them may open into one of the lateral canals above re-
ferred to. The palatine vault is concave, uneven, perforated by numerous nutri-
tious foramina, marked by depressions for the palatal glands, and crossed by a
BASE OF SKULL.
59
crucial suture, which indicates the point of junction of the four bones of which
it is composed. One or two small foramina, seen in the alveolar margin behind
51. — Base of Skull. External Surface.
A/it. pala/ti'/ne fossa
^mJiSTnlts left Mi'SO'/ialiCt. n.
nsmlts A^ni.palaT. vess.
Transmiis rigJOi Naso-faZoJl. n..
Aectis soTy palatine
Fm-amiTha.
Post.NcLscttl SpCiie.
AZVaOS UVUL/E
RarruHar j>ree
^^Ji^noid.pros, of Pcohote.
TENSOR TYNlPflNI.
-PJiaryiufcal Spine. fvT suP. constrict.
'it^ of j:astacMin tu.la&LCanalfarJenso.r Tymf
LAXATOR TYWPAWf.
Caiml for JacolsmCs n.
—Aqiiedtict. CucIiUn..
For.liwcri<.m,posteTiu.s.
CaiialftrrArnold.'s n.
lu-ricular fissicre-
6o OSTEOLOGY.
the incisor teeth, occasionally seen in the adult, almost constant in young subjects,
are called the incisive foramina; they transmit nerves and vessels to the incisor
teeth. At each posterior angle is the posterior palatine foramen, for the transmis-
sion of the posterior palatine vessels and anterior palatine nerve, and running for-
wards and inwards from it a groove, which lodges the same vessels and nerve.
Behind the posterior palatine foramen is the tuberosity of the palate bone, perforated
by one or more accessory posterior palatine canals, and marked by the commencement
of a ridge, which runs transversely inwards, and serves for the attachment of the
tendinous expansion of the tensor palati muscle. Projecting backwards from the
centre of the posterior border of the hard palate is the posterior nasal spine, for
the attachment of the Azygos uvulfe. Behind and above the hard palate is the
posterior aperture of the nares, divided into two parts by the vomer, bounded
above by the body of the sphenoid, below by the horizontal plate of the palate
bone, and laterally by the pterygoid processes of the sphenoid. Each aperture
measures about an inch in the vertical, and half an inch in the transverse direc-
tion. At the base of the vomer may be seen the expanded alse of this bone,
receiving between them the rostrum of the sphenoid. Near the lateral margins of
the vomer, at the root of the pterygoid process, are the pterygo-palatine canals.
The pterygoid process, which bounds the posterior nares on each side, presents
near its base the pterygoid or Vidian canal, for the Vidian nerve and artery.
Each process consists of two plates, which bifurcate at the extremity to receive
the tuberosity of the palate bone, and are separated behind by the pterygoid fossa,
which lodges the Internal pterygoid muscle. The internal plate is long and nar-
row, presenting on the outer side of its base the scaphoid fossa, for the origin of
the Tensor palati muscle, and at its extremity the hamular process, around which
the tendon of this muscle turns. The external pterygoid plate is broad, forms
the inner boundary of the zygomatic fossa, and affords attachment to the External
pterygoid muscle.
Behind the nasal fossa in the middle line is the basilar surface of the occipital
bone, presenting in its centre the pharyngeal spine for the attachment of the
Superior constrictor muscle of the pharynx, with depressions on each side for the
insertion of the Rectus anticus major and minor. At the base of the external
pterygoid plate is the foramen ovale; behind this, the foramen spinosum, and the
prominent spinous process of the sphenoid, which gives attachment to the internal
lateral ligament of the lower jaw and the Laxator tympani muscle. External to
the spinous process is the glenoid fossa, divided into two parts by the Glaserian
fissure, the anterior portion being concave, smooth, bounded in front by the eminentia
articularis, and serving for the articulation of the condyle of the lower jaw; the
posterior portion rough, bounded behind by the vaginal process, and serving for
the reception of part of the parotid gland. Emerging from between the laminas
of the vaginal process is the styloid process; and at the base of this process is the
stylo-mastoid foramen, for the exit of the facial nerve, and entrance of the stylo-
mastoid artery. External to the stylo-mastoid foramen is the auricular fissure
for the auricular branch of the pneumogastric, bounded behind by the mastoid
process. Upon the inner side of this process is a deep groove, the digastric fossa;
and a little more internally, the occipital groove, for the occipital artery. At the
base of the internal pterygoid plate is a large and somewhat triangular aperture,
the foramen lacerum medium, bounded in front by the great wing of the sphenoid,
behind by the apex of the petrous portion of the temporal bone, and internally by
the body of the sphenoid and basilar process of the occipital bone; it presents in
front the posterior orifice of the Vidian canal, behind the aperture of the carotid
canal. This opening is filled up in the recent subject by a fibro-cartilaginous
substance; across its upper or cerebral aspect passes the internal carotid artery
and Vidian nerve. External to this aperture, the petro-sphenoidal suture is
observed, at the outer termination of which is seen the orifice of the canal for the
Eustachian tube, and that for the Tensor tympani muscle. Behind this suture is
seen the under surfixce of the petrous portion of the temporal bone, presenting,
LATERAL REGION OF THE SKULL. 6i
from within outwards, the quadrilateral rough surface, part of which affords
attachment to the Levator palati and Tensor tympani muscles ; behind this surface
are the orifices of the carotid canal and the aquEeductus cochleae, the former trans-
mitting the internal carotid artery and the ascending branches of the superior
cervical ganglion of the sympathetic, the latter serving for the passage of a small
artery and vein to the cochlea. Behind the carotid canal is a very large irregular
aperture, the jugular fossa, formed in front by the petrous portion of the temporal,
and behind by the occipital; it is generally larger on the right than on the left
side, and is perforated at the bottom by an irregular aperture ; it is divided into two
parts by a ridge of bone, which projects usually from the temporal; the anterior,
or smaller portion, transmitting the three divisions of the eighth pair of nerves;
the posterior, transmitting the internal jugular vein and the two ascending menin-
geal vessels, from the occipital and ascending pharyngeal arteries. On the ridge
of bone dividing the carotid canal from the jugular fossa, is the small foramen for
the transmission of the tympanic nerve; and on the outer wall of the jugular
foramen, near the root of the styloid process, is the small aperture for the trans-
mission of Arnold's nerve. Behind the basilar surface of the occipital bone is the
foramen magnum, bounded on each side by the condyles, rough internally for the
attachment of the alar ligaments, and presenting externally a rough surface, the
jugular process, which serves for the attachment of the Rectus lateralis. On either
side of each condyle anteriorly is the anterior condyloid fossa, perforated by the
anterior condyloid foramen, for the passage of the lingual nerve. Behind each
condyle are the posterior condyloid foss«, perforated on one or both sides by the
posterior condyloid foramina, for the transmission of a vein to the lateral sinus.
Behind the foramen magnum is the external occipital crest, terminating above at
the external occipital tuberosity, whilst on each side are seen the superior and
inferior curved lines; these, as well as the surfaces of the bone between them,
being rough for the attachment of numerous muscles.
Lateral Regions op the Skull.
The Lateral Regions of the Skull are somewhat of a triangular form, their
base being formed by a line extending from the external angular process of
the frontal bone along the temporal ridge backwards to the outer extremity of the
superior curved line of the occiput; and the sides being formed by two lines, the
one drawn downwards and backwards from the external angular process of the
frontal bone to the angle of the lower jaw, the other from the angle of the jaw
upwards and backwards to the extremity of the superior curved line. This
region is divisible into three portions, temporal, mastoid, and zygomatic.
The Temporal Foss^.
The Temporal Portion, or fossa, is bounded above and behind by the temporal
ridge, which extends fi-om the external angular process of the frontal upwards and
backwards across the frontal and parietal bones, curving downwards behind to
terminate at the root of the zygomatic process. La front, it is bounded by the
frontal, malar, and great wing of the sphenoid: externally, by the zygomatic arch,
formed conjointly by the malar and temporal bones; below, it is separated from
the zygomatic fossa by the pterygoid ridge, seen on the under surface of the great
wing of the sphenoid. This fossa is formed by five bones, part of the frontal,
great wing of the sphenoid, parietal, squamous portion of the temporal, and malar
bones, and is traversed by five sutures, the transverse facial, coronal, spheno-
parietal, squamo-parietal, and squamo- sphenoidal. It is deeply concave in front,
convex behind, traversed by numerous grooves for lodging the branches of the
deep temporal arteries, and filled by the temporal muscle.
The Mastoid Portion is bounded in front by the anterior horizontal root of the
zygoma; above, by a line which corresponds with the posterior root of the zygoma
and the masto-parietal suture; behind and inferior ly, by the masto-occipital suture.
It is formed by the mastoid and part of the squamous portion of the temporal bone;
62 OSTEOLOGY.
its surface is convex and rough for the attachment of muscles, and presents, from
behind forwards, the mastoid foramen, below the mastoid process. In front of the
mastoid process is the external auditory meatus, surrounded by the auditory pro-
cess. Anterior to the meatus is the Glenoid fossa, bounded in front by the tubercle
of the zygoma, behind by the auditory process, and above by the middle root of
the zygoma, which terminates at the Glaserian fissure.
The Ztgomatic Foss^.
The Zygomatic fossae, are two irregular-shaped cavities, situated one on each
side of the head, below, and on the inner side of the zygoma ; bounded in
front by the tuberosity of the superior maxillary bone and the ridge which
descends from its malar process; behind, by the posterior border of the pterygoid
process; above, by the pterygoid ridge on the under surface of the great wing of
the sphenoid and squamous portion of the temporal; below, by the alveolar
border of the superior maxilla; internally, by the external pterygoid plate; and
externally, by the zygomatic arch and ramus of the jaw. It contains the lower
part of the Temporal, the External, and Internal pterygoid muscles, the internal
maxillary artery, the inferior maxillary nerve, and their branches. At its upper
and inner part may be observed two fissures, the spheno-maxillary and pterygo-
maxillary.
The Spheno-maxillary fissure, horizontal in direction, opens into the outer and
back part of the orbit. It is formed above by the lower border of the orbital
surface of the great wing of the sphenoid; below, by the posterior rounded border
of the superior maxilla and a small part of the palate bone; externally, by a small
part of the malar bone; internally, it joins at right angles with the ptery go-
maxillary fissure. This fissure opens a communication from the orbit into three
fossae, the temporal, zygomatic, and spheno-maxillary; it transmits the superior max-
illary nerve, infra-orbital artery, and ascending branches from Meckel's ganglion.
The Ptery go -maxillary fissure is vertical, and descends at right angles from
the inner extremity of the preceding; it is a triangular interval, formed by the
divergence of the superior maxillary bone from the pterygoid process of the
sphenoid. It serves to connect the spheno-maxillary fossa with the zygomatic,
and transmits branches of the internal maxillary artery.
Thk Spheno-maxillary Fossa.
The Spheno-maxillary fossa is a small triangular space situated at the angle of
junction of the spheno-maxillary and pterygo-maxillary fissures, and placed beneath
the apex of the orbit. It is formed above by a small part of the under surface of
the body of the sphenoid; in front, by the superior maxillary bone; behind, by the
pterygoid process of the sphenoid; internally by the vertical plate of the palate;
externally, it communicates with the spheno-maxillary fissure. This fossa has three
fissures terminating in it, the sphenoidal, spheno-maxillary, and pterygo-maxillary;
it communicates with three fossae, the orbital, nasal, and zygomatic, and with the
cavity of the cranium, and has opening into it five foramina. Of these there are
three on the posterior wall, the foramen rotundum above, the Vidian below and
internal, and still more inferior and internal, the pterygo-palatine. On the inner
wall is the spheno-palatine foramen by which it communicates with the nasal fossa,
and below, the superior orifice of the posterior palatine canal, besides occasionally
the orifices of two or three accessory posterior palatine canals.
Anterior Region of the Skull. (Fig. 52.)
The Anterior Region of the Skull, which forms the face, is of an oval form,
presents an irregular surface, and is excavated for the reception of the two prin-
cipal organs of sense, the eye and the nose. It is bounded above by the nasal
eminences and margins of the orbit; below, by the prominence of the chin; on each
side, by the malar bone, and anterior margin of the ramus of the jaw. In the
median line are seen from above downwards, the nasal eminences, which indicate
ANTERIOR REGION OF THE SKULL.
63
the situation of the frontal sinuses; diverging outwards from them, the super-
ciliary ridges which support the eyebrows. Beneath the nasal eminences is the
arch of the nose, formed by the nasal bones, and the nasal process of the superior
maxillary. The nasal arch is convex from side to side, concave from above down-
wards, presenting in the median line the inter-nasal suture, formed between the
nasal bones, laterally the naso-maxillary suture, formed between the nasal and the
nasal process of the superior maxillary bones, both these sutures terminating above
in that part of the transverse suture which connects the nasal bones and nasal pro-
cesses of the superior maxillary with the frontal. Below the nose is seen the
heart-shaped opening of the anterior nares, the narrow end upwards, and broad
below; it presents laterally the thin sharp margins which serve for the attachment
52. — Anterior Eegion of the Skull.
TENBO OCUJLr
Amt. Nasal /SiptTie
Incisive fossd-
of the lateral cartilages of the nose, and in the middle line below, a prominent
process, the anterior nasal spine, bounded by two deep notches. Below this is the
intermaxillary suture, and on each side of it the incisive fossa. Beneath this fossa
is the alveolar process of the upper and lower jaw, containing the incisive teeth,
and at the lower part of the median line, the symphysis of the chin, the mental
emine'nce, and the incisive fossa of the lower jaw.
Proceeding from above downwards, on each side are the supra orbital ridges,
terminating externally in the external angular process at its junction with the
malar, and internally in the internal angular process; towards the inner third of
this ridge is the supra orbital notch or foramen, for the passage of the supra or-
bital vessels and nerve, and at its inner side a slight depression for the attachment
64 OSTEOLOGY.
of the cartilaginous pulley of the superior oblique muscle. Beneath the supra-
orbital ridges are the openings of the orbits, bounded externally by the orbital
ridge of the malar bone ; below, by the orbital ridge formed by the malar, superior
maxillary, and lachrymal bones; internally, by the nasal process of the superior
maxillary, and the internal angular process of the frontal bone. On the outer
side of the orbit, is the quadrilateral anterior surface of the malar bone, perforated
by one or two small malar foramina. Below the inferior margin of the orbit, is
the infra-orbital foramen, the termination of the infra-orbital canal, and beneath
this, the canine fossa, which gives attachment to the Levator anguli oris; bounded
below by the alveolar processes, containing the teeth of the upper and lower jaw.
Beneath the alveolar arch of the lower jaw is the mental foramen for the passage
of the mental nerve and artery, the external oblique line, and at the lower border
of the bone, at the point of junction of the body with the ramus, a shallow groove
for the passage of the facial artery.
The Orbits.
The Orbits (fig. 52) are two quadrilateral hollow cones, situated at the upper and
anterior part of the face, their bases being directed forwards and outwards, and their
apices backwards and inwards. Each orbit is formed of seven bones, the frontal, sphe-
noid, ethmoid, superior maxillary, malar, lachrymal and palate; but three of these, the
frontal, ethmoid and sphenoid, enter into the formation of both orbits, so that the two
cavities are formed of eleven bones only. Each cavity presents for examination,
a roof, a floor, an inner and an outer wall, a circumference or base, and an apex.
The Roof is concave, directed downwards and forwards, and formed in front by
the orbital plate of the frontal; behind, by the lesser wing of the sphenoid. This
surface presents internally the depression for the fibro-cartilaginous pulley of the
superior oblique muscle; externally, the depression for the lachrymal gland, and
posteriorly, the suture connecting the frontal and lesser wing of the sphenoid.
The Floor is nearly flat, and of less extent than the roof; it is formed chiefly by
the orbital process of the superior maxillary; in front, to a small extent, by the
orbital process of the malar, and behind, by the orbital surface of the palate.
This surface presents at its anterior and internal part, just external to the lachry-
mal canal, a depression for the attachment of the tendon of origin of the inferior
oblique muscle; externally, the suture betw-een the malar and superior maxillary
bones; near its middle, the infra-orbital groove; and posteriorly, the suture between
the maxillary and palate bones.
The Inner Wall is flattened, and formed from before backwards by the nasal
process of the superior maxillary, the lachrymal, os planum of the ethmoid, and
a small part of the body of the sphenoid. This surface presents the lachrymal
groove, and crest of the lachrymal bone, and the sutures connecting the ethmoid,
in front, with the lachrymal, behind, with the sphenoid.
The Outer Wall is formed in front by the orbital process of the malar bone;
behind, by the orbital plate of the sphenoid. On it are seen the orifices of one or
two malar canals, and the suture connecting the sphenoid and malar bones.
Angles. The superior external angle is formed by the junction of the upper
and outer walls; it presents from before backwards, the sutures connecting the
frontal with the malar in front, and with the orbital plate of the sphenoid behind;
quite posteriorly is the foramen lacerum anterius, or sphenoidal fissure, which
transmits the third, fourth, ophthalmic division of the fifth, and sixth nerves,
and the ophthalmic vein. The superior internal angle is formed by the junction
of the upper and inner wall, and presents the suture connecting the frontal with
the lachrymal in front, and with the ethmoid behind. This suture is perforated
by two foramina, the anterior and posterior ethmoidal, the former transmitting
the anterior ethmoidal artery and nasal nerve, the latter the posterior ethmoidal
artery and vein. The inferior external angle, formed by the junction of the
outer wall and floor, presents the spheno-maxillary fissure, which transmits the
infra-orbital vessels and nerve, and the ascending branches from the spheno-palatine
NASAL FOSS^
65
ganglion. The inferior internal angle is formed by the union of the lachrymal
and OS planum of the ethmoid, with the superior maxillary and palate bones. The
circumference, or base, of the orbit, quadrilateral in form, is bounded above by the
supra-orbital arch; below, by the anterior border of the orbital plate of the malar,
superior maxillary, and lachrymal bones; externally, by the external angular
process of the frontal and malar bone; internally, by the internal angular process
of the frontal and nasal process of the superior maxillary. The circumference is
marked by three sutures, the fronto-maxillary internally, the fronto-malar exter-
nally, and the malo-maxillary below; it contributes to the formation of the la-
chrymal groove, and presents above, the supra-orbital notch (or foramen), for the
passage of the supra-orbital artery, veins, and nerve. The apex, situated at the
back of the orbit, corresponds to the optic foramen, a short circular canal, which
transmits the optic nerve and ophthalmic artery. It will thus be seen that there
are nine openings communicating with each orbit, viz., the optic, foramen lacerum
anterius, spheno-maxillary fissure, supra-orbital foramen, infra-orbital canal, ante-
rior and posterior ethmoidal foramina, malar foramina, and lachrymal canal.
The Nasal Foss^.
The Nasal Fosscb are two large irregular cavities, situated in the middle line of
the face, separated from each other by a thin vertical septum, and extending from
the base of the cranium to the roof of the mouth. They communicate by two large
apertures, the anterior nares, with the front of the face, and with the pharynx
behind by the two posterior nares. These fossae are much narrower above than
below, and in the middle than at the anterior or posterior openings: their depth,
which is considerable, is much greater in the middle than at either extremity.
Each nasal fossa communicates with four sinuses, the frontal in front, the sphe-
noidal behind, and the maxillary and ethmoidal on either side. Each fossa also
communicates with four cavities: with the orbit by the lachrymal canal, with the
mouth by the anterior palatine canal, with the cranium by the olfactory foramina,
and with the spheno-maxillary fossa by the spheno-palatine foramen; and they
occasionally communicate with each other by an aperture in the septum. The
bones entering into their formation are fourteen in number: three of the cranium,
the frontal, sphenoid, and ethmoid, and all the bones of the face excepting the
malar and lower jaw. Each cavity has four walls, a roof, a floor, an inner, and
an outer wall.
The upper wall, or roof (fig. 53), is long, narrow, and concave from before
backwards; it is formed in front by the nasal bones and nasal spine of the frontal,
which are directed downwards and forwards; in the middle, by the cribriform
lamella of the ethmoid, which is horizontal; and behind, by the under surface of
the body of the sphenoid, and sphenoidal turbinated bones, which are directed
downwards and backwards. This surface presents, from before backwards, the
internal aspect of the nasal bones; on their outer side, the suture formed between
the nasal, with the nasal process of the superior maxillary ; on their inner side, the
elevated crest which receives the nasal spine of the frontal and the perpendicular
plate of the ethmoid, and articulates with its fellow of the opposite side; whilst
the surface of the bones is perforated by a few small vascular apertures, and pre-
sents the longitudinal groove for the nasal nerve: further back is the transverse
suture, connecting the frontal with the nasal in front, and the ethmoid behind,
the olfactory foramina on the under surface of the cribriform plate, and the suture
between it and the sphenoid behind: quite posteriorly are seen the sphenoidal tur-
binated bones, the orifice of the sphenoidal sinuses, and the articulation of the ala?
of the vomer with the under surface of the body of the sphenoid.
Th.Q floor is flattened from before backwards, concave from side to side, and
wider in the middle than at either extremity. It is formed in front by the palate
process of the superior maxillary; behind, by the palate process of the palate
bone. This surface presents, from before backwards, the anterior nasal epine;
behind this, the upper orifice of the anterior palatine canal; internally, the ele-
p
66
OSTEOLOGY.
vated crest which articulates with the vomer; and behind, the suture between
the palate and superior maxillary bones, and the posterior nasal spine.
^3._Roof, Floor, and Outer Wall of Nasal Fossae.
Eoof
Nnsal iSpine of J' rcmtal Se
JLmssontaL Plate rfJSfhm^.ul
JNaso-IaeAiyo/ia-l Ca-nal
Bnstle fassed thnu^Tl
li^uTidCiwluni ■
Oioter WalZ
Ncisab Proc. cfSapMaa.
ncifo77njJ?roe ef ditto
InfiLTLor Turbvnaicd
Palate
'uj/ercor Meatus .
Middle, Meafu,s
Inferior Meatur
Floor
ATa.NcLspjl Sjpi.Tie
Palate Procof Sii^Max.
Folate Froc. of Ta/ate
Post.ITcbsal iSpine,
A.nt. P'wlaiti7ie Canal -
The inner wall, or septum (fig. 54), is a thin vertical septum, which separates
the nasal foss£e from one another; it is occasionally perforated, so that they com-
municate, and is frequently deflected considerably to one side. It is formed, in
front, by the crest of the nasal bones and nasal spine of the frontal; in the middle,
by the perpendicular lamella of the ethmoid; behind, by the vomer and rostrum
of the sphenoid; below, by the crest of the superior maxillary and palate bones.
It presents, in front, a large triangular notch, which receives the triangular carti-
lage of the nose; above, the lower orifices of the olfactory canals; and behind, the
guttural edge of the vomer. Its surface is marked by numerous vascular and ner-
vous canals, and traversed by sutures connecting the bones of which it is formed.
The outer wall is formed, in front, by the nasal process of the superior maxil-
lary and lachrymal bones ; in the middle, by the ethmoid and inner surface of the
superior maxillary and inferior turbinated bones; behind, by the vertical plate of
the palate bone. This surface presents three irregular longitudinal passages, or
meatuses, formed between three horizontal plates of bone that spring from it; they
are termed the superior, middle, and inferior meatuses of the nose. The superior
meatus, the smallest of the three, is situated at the upper and back part of each
nasal fossa, occupying the posterior third of the outer wall. It is situated between
the superior and middle turbinated bones, and has opening into it two foramina, the
spheno-palatine, at the back part of its outer wall, the posterior ethmoidal cells, at
the front part of the upper wall. The opening of the sphenoidal sinuses is usually
at the upper and back part of the nasal fossas, immediately behind the superior
turbinated bone. The middle meatus, situated between the middle and inferior
turbinated bones, occupies the posterior two-thirds of the outer wall of each nasal
fossa. It presents two apertures. In front is the orifice of the infundibulum, by
which the middle meatus communicates with the anterior ethmoidal cells, and
NASAL F0SS7K.
67
through these with the frontal sinuses. At the centre of the outer wall is the
orifice of the antrum, which varies somewhat as to its exact position in different
skulls. The inferior meatus, the largest of the three, is the space between the
inferior turbinated bone and the floor of the nasal fossa. It extends along the
entire length of the outer wall of the nose, is broader in front than behind, and
presents anteriorly the lower orifice of the lachrymal canal.
54. — Inner "Wall of Nasal Fossfe, or Septum of Nose.
CresP of Wasal lone.
ffasat String of Frontal B.-
Spcice for Triangidar
Cartilage oj SeptTim
Ores t of Pculal/e Eione
Crest of Suf ■ Max-iTL.Bone
Os Hyoides.
The Hyoid bone is named from its resemblance to the Greek Upsilon; it is also
called the lingual hone, from supporting the tongue, and giving attachment to its
numerous muscles. It is a bony arch, shaped like a horse-shoe, and consisting of
five segments, a central portion or body, two greater cornua, and two lesser cornua.
55. — Hyoid Bone. Anterior Surface.
The Body forms the central part of the
bone, is of a quadrilateral form, its anterior
surface (fig. 55) convex, directed forwards
and upwards, and divided into two parts by
a vertical ridge, which descends along the
median line, and is crossed at right angles
by a horizontal ridge, so that this surface is
divided into four muscular depressions. At
the point of meeting of these two lines is a
prominent elevation, the tubercle. The por-
tion above the horizontal ridge is directed
upwards, and is sometimes described as the
superior border. The anterior surface gives attachment to the Genio-hyoid in the
greater part of its extent; above, to the Genio-hyo-glossus; below, to the Mylo-
hyoid, Stylo-hyoid, and aponeurosis of the Digastric; and between these to part of
the Hyo-glossus. The posterior surface is smooth, concave, directed backwards
and downwards, and separated from the epiglottis by the thyro-hyoid membrane,
and by a quantity of loose areolar tissue. The superior border is rounded, and
F 2
68 OSTEOLOGY.
gives attachment to the thyro-hyoid membrane, and part of the Genio-hyo-glossi
muscles. The inferior border gives attachment in front to the Sterno-hyoid, be-
hind to part of the Thyro-hyoid, and to the Omo-hyoid at its junction with the
great cornu. The lateral surfaces are small, oval, convex facets, covered with
cartilage for articulation with the greater cornua.
The Greater Cornua project backwards from the lateral surfaces of the body,
they are flattened from above downwards, diminish in size from before backwards,
and terminate posteriorly in a tubercle for the attachment of the thyro-hyoid
lio-ament. Their outer surface gives attachment to the Hyo-glossus; their upper
border, to the Middle constrictor of the pharynx; their lower border, to part of the
Thyro-hyoid muscle.
The Lesser Cornua are two small conical shaped eminences, attached by their
bases to the angles of junction between the body and greater cornua, and giving
attachment by their apices to the stylo-hyoid ligaments. In youth the cornua are
connected to the body by cartilaginous surfaces and held together by ligaments; in
middle life, the body and greater cornua usually become joined; and in old age
all the segments are united together, forming a single bone.
Development. 'Qj Jive centres; one for the body and one for each cornu. Ossi-
fication commences in the body and greater cornua towards the end of foetal life,
those for the cornua first appearing. Ossification of the lesser cornua commences
some months after birth.
Attachment of Muscles. Sterno-hyoid, Thyro-hyoid, Omo-hyoid, aponeurosis
of the Digastricus, Stylo-hyoid, Mylo-hyoid, Genio-hyoid, Genio-hyo-glossus, Hyo-
glossus, Middle constrictor of the pharynx, and occasionally a few fibres of the
Lingualis. It also gives attachment to the thyro-hyoidean membrane, and the
stylo-hyoid, thyro-hyoid, and hyo-epiglottic ligaments.
THE THORAX.
The Thorax or chest is an osseo-cartilaginous cage, intended to contain and pro-
tect the principal organs of respiration and circulation. It is the largest of the
three cavities connected with the spine, and is formed by the sternum and costal
cartilages in front, the twelve ribs on each side, and the bodies of the dorsal ver-
tebrte behind.
The Sternum.
The Sternum (figs. 56, 57) is a flat narrow bone, situated in the median line of
the front of the chest, and consisting in the adult of three portions. Its form
resembles an ancient sword: the upper piece representing the handle, is termed the
manubrium, the middle and largest piece which represents the chief part of the
blade, is termed the gladiolus, and the inferior piece like the point of the sword,
is termed the ensiform or xiphoid appendix. Li its natural position, its direction
is oblique, its anterior surface looking upwards and forwards, its posterior down-
wards and backwards. It is flattened in front, concave behind, broad above,
becoming narrowed at the point where the first and second pieces are connected,
after which it again widens a little, and is pointed at its extremity.
The First Piece of the sternum or Manubrium, is of a somewhat triangular
form, broad and thick above, narrowed below at its junction with the middle piece.
Its anterior surface convex from side to side, concave from above downwards, is
smooth and affords attachment on each side to the Pectoralis major and sternal
origin of the Sterno-cleido-mastoid muscle. In well marked bones, ridges limiting
the attachment of these muscles are very distinct. Its posterior surface, concave
and smooth, affords attachment on each side to the Sterno-hyoid and Sterno-thyroid
muscles. The superior border, the thickest, presents at its centre the interclavi-
cular notch, and on each side an oval articular surface, directed upwards backwards
snd outwards, for articulation with the sternal end of the clavicle. The inferior
border presents an oval rough surface, covered in the recent state with a thin layer
of cartilage, for articulation with the second portion of the bone. The lateral
borders are marked superiorly by an articular depression for the first costal carti-
STERNUM.
56.— Sternum and Costal Cartilages. Anterior Surface.
69
BTERNO-CttlBO MASTOro
6UBCLAVIUS \ •^
57. — Posterior Surface of Sternum.
70
OSTEOLOGY.
lage, and below by a half facet, which, with a similar facet on the upper angle of
the middle portion of the bone, forms a notch for the reception of the costal car-
tilage of the second rib. These articular surfaces are separated by a curved edge
which slopes from above downwards and inwards.
The Second Piece of the sternum, or gladiolus, considerably longer, narrower,
and thinner than the superior, is broader below than above. Its anterior surface
is nearly flat, directed upwards and forwards, and marked by three transverse lines
which cross the bone opposite the third, fourth, and fifth articular depressions.
These lines indicate the point of union of the four separate pieces of which this
part of the bone consists at an early period of life. At the junction of the third
and fourth pieces, is occasionally seen an orifice, the sternal foramen; it varies in
size and form in difierent individuals, and pierces the bone from before backwards.
This surface afibrds attachment on each side to the sternal origin of the Pectoralis
major. The posterior surface, slightly concave, is also marked by three transverse
lines; but they are less distinct than those on the anterior surface; this surface
affords attachment below, on each side, to the Triangularis sterni muscle, and occa-
sionally presents the posterior opening of the sternal foramen. The superior border
is marked by an oval surface for articiilation with the manubrium. The inferior
border is narrow and articulates with the ensiform appendix. Each lateral border
presents five articular depressions; the first, at each superior angle, is a half facet
for the lower half of the cartilage of the second rib, the three succeeding depres-
sions receive the cartilages of the third, fourth, and fifth ribs, whilst each inferior
angle presents a half facet for the upper half of the cartilage of the seventh rib.
These depressions are separated by a series of curved inter-articular notches,
which diminish in length from above downwards.
The Third Piece of the sternum, the ensiform or xiphoid appendix, is the small-
est of the three; it is thin and elongated in form, cartilaginous in structure in youth,
but more or less ossified at its upper part in the adult. Its anterior surface afibrds
attachment to the costo-xiphoid ligaments. Its posterior surface, to some of the
fibres of the Diaphragm and Triangularis sterni muscles. Its lateral borders, to
the aponeurosis of the abdominal muscles. Above, it is continuous with the lower
end of the gladiolus; below, by its pointed extremity, it gives attachment to the
linea alba, and at each superior angle presents a half facet for the lower half of
the cartilage of the seventh rib. This portion of the sternum is very various in
appearance, being sometimes pointed, broad and thin, sometimes bifid, or perforated
by a round hole, occasionally curved, or deflected considerably to one or the other
side.
Structure. This bone is composed of a considerable amount of loose spongy
tissue within, covered externally with a very thin layer of compact tissue.
Development. The sternum, including the ensiform appendix, is developed
by six centres. One for the first piece or manubrium, four for the second
piece or gladiolus, and one for the ensiform appendix. The sternum is entirely
cartilaginous up to the middle of foetal life, and when ossification takes place, the
ossific granules are deposited in the middle of the intervals between the articular
depressions for the costal „t^t ,pr,, -, r^- ^ .
^^•1 • ^1, J? 11 • 58. — Development of Sternum, bv Six Centres,
cartilages, m the lollowmg ^ ' -^
order (fig. 58). In the
first piece, between the fifth
and sixth months; in the
second and third, between
the sixth and seventh;
in the fourth piece, at the
ninth month; in the fifth,
within the first year, or
between the first and
second years after birth;
and in the ensiform appen-
r
m.
Of MJjLiiahriiium
Ti'j}h£-
(
t '
mXZ
D
f'l
'J
' ,
If for 2V^Jpl&re
"~) or
-' Gladi.alu,s
3
, 1 (?-7 mo.
"biM
O'
\ej
IforHnsifoTm 1
" Cartoluge
Z?f-fS^^lj.^-
STERNUM.
71
cax^ept Cncloia.qc
3S-l^O.
Z0-2S(h yeur
soon a4^ter piiiertv
rlly eartila/.
pcoruy can
advanced life
i/wus in
60. — Peculiarities.
nump&T
^/
for l-fvoece Zw tiwi'e reritres
Z^.?' 'piece, icsuctMif ont
s..
4i? ; ^- placed laterO'llij
dix, between the (second 59-
and the seventeenth or
eighteenth years, by a
single centre which makes
its appearance at the upper
part, and proceeds gra-
dually downwards. To
these may be added the
occasional existence, as de-
scribed by Breschet, of
two small epi- sternal cen-
tres, which make their ap-
pearance one on each side
of the interclavicular notch.
It occasionally happens that
some of these divisions are
formed from more than one
centre, the number and posi-
tion of which vary (fig. 60).
Thus the first piece may
have two, three, or even
six centres; the second
piece has seldom more than
one; the third, fourth, and
fifth pieces, areoften formed Centres
from two centres placed
laterally, the irregular
union of which will serve
to explain the occasional
occurrence of the sternal
foramen (fig. 61), or of the
vertical fissure which occa-
sionally intersects this part
of the bone. Union of these
various parts commences
from below, and proceeds ri/zc/ in
upwards, taking place in Mode of
the following order (fig.59). Uvion
The fifth piece is joined
to the fourth soon after
puberty; the fourth to the
third,between the twentieth
and twenty-fifth years; the
third to the second, be-
tween the thirty-fifth and
fortieth years; the second
is rarely joined to the first except in very advanced age.
Articulations. With the clavicles, and seven costal cartilages on each side.
Attachment of Muscles. The Pectoralis major, Sterno-cleido-mastoid, Sterno-
hyoid, Sterno-thyroid, Triangularis sterni, aponeurosis of the Obliquus externus,
Obliquus internus, and Transversalis muscles. Rectus and Diaphragm.
The Ribs,
The Ribs are elastic arches of bone, which form the chief part of the thoracic
walls. They are twelve in number on each side; bijt this number may be increased
by the development of a cervical or lumbar rib, or maybe diminished to eleven. The
first seven are connected behind with the spine, and in front with the sternum.
61.
Arres'f. of DetA^loptnent
cf laterai jjiec^.i producihc/
Ster'iial fissiJbre. k
Sternal foramen
72
OSTEOLOGY.
through the Intervention of the costal cartilages, they are called vertebrosternal,
or true ribs. The remaining five are false ribs; of these the first three, being
62, — A Central Rib of Right Side. connected behind with the spine, and in
Inner Surface.
front with the costal cartilages, are called
the vertebro-costal ribs; the last two are
connected with the vertebrae only, being
free at their anterior extremities, they are
termed vertebral or floating ribs. The
ribs vary in their direction, the upper ones
being placed nearly at right angles with
the spine; the lower ones are placed
obliquely, so that the anterior extremity
is lower than the posterior. The extent
of obliquity reaches its maximum at the
ninth rib, gradually decreasing from that
point towards the twelfth. The ribs are
situated one beneath the other in such
a manner that spaces are left between
them; these are called intercostal spaces.
Their length corresponds to the length of
the ribs, their breadth is more considerable
in front than behind, and between the
upper than between the lower ribs. The
ribs increase in length from the first to
the eighth, when they again diminish to
the twelfth. In breadth they decrease
from above downwards; in each rib the
greatest breadth is at the sternal extre-
mity.
Common characters of the Ribs{^g.62).
Take a rib from the middle of the series
in order to study its common characters.
Each rib presents two extremities, a pos-
terior or vertebral, an anterior or sternal,
and an intervening portion, the body or
shaft. The posterior or vertebral extre-
mity, presents for examination a head,
neck, and tuberosity.
The head (fig. 63) is marked by a kid-
ney-shaped articular surface, divided by a
horizontal ridge into two facets for articu-
lation with the costal cavity formed by the
junction of the bodies of two contiguous
dorsal vertebrae; the upper facet is small,
the inferior one of large size; the ridge
separating them, serves for the attachment
of the inter-articular ligament.
The neck is that flattened portion of the
rib which extends outwards from the head;
it is about an inch long, and rests upon
the transverse process of the inferior of
the two vertebras with which the head
articulates. Its anterior surface is flat
and smooth, its posterior rough, for the
attachment of the middle costo-transverse
ligament. Of its two borders, the super-
rior presents a rough crest for the attach-
RIBS. 73
ment of the anterior costo-transverse ligament; its inferior border is rounded.
On tlie outer surface of tlie neck, just wliere it joins tlie siiaft, is an eminence, tlie
tuberosity; it consists of two portions, an articular and a non-articular. The
articular portion, the most internal and inferior of the two, presents a small oval
surface directed downwards, backwards and inwards, for articulation with the
extremity of the transverse process of the vertebra below it. The non-articulm
portion is a rough elevation, which affords attachment to the posterior costo-trans-
verse ligament.
63. — Vertebral Extremity of a Eib. External Surface.
lor At^^T. Cnsto-tTMisLigS
Facet fur body of lupjiev Horsal Ve/l-tehra/^
Rid/ue for T-nteT-artLcidar Ligt^'
facet for liody of lower Dorsccl Yert^^
for tranav.^roc. of lovret
The shaft presents two surfaces, an external and an internal; and two borders,
a superior and an inferior. The external surface is convex, and marked for the
attachment of muscles. At its posterior part, a little in front of the tuberosity, is
seen a prominent line, directed obliquely from above, downwards and outwards;
this gives attachment to a tendon of the Sacro-lumbalis muscle, and is called the
angle. At this point, the rib is bent upon itself in two directions. If the rib is
laid upon its lower border, it will be seen that the anterior portion of the shaft, as
far as the angle, rests upon this surface, while the vertebral end of the bone,
beyond the angle, is bent inwards and at the same time tilted upwards. The
distance between the angle and the tuberosity increases gradually from the second
to the tenth rib. This portion of bone is rounded, rough, and irregular, and
serves for the attachment of the Longissimus dorsi. The portion of bone between
the angle and sternal extremity is also slightly twisted upon its own axis, the
external surface looking downwards behind the angle, a little upwards in front of
it. This surface presents, towards its sternal extremity, an oblique line, the ante-
rior angle. The internal surface is concave, smooth, and presents the orifices of
two or three nutrient foramina, the course of which is directly backwards towards
the vertebral extremity. This surface looks a little upwards, behind the angle; a
little downwards, in front of it. The superior border, thick and rounded, is marked
by an external and an internal lip, more distinct behind than in front; they serve
for the attachment of the External and Internal intercostal muscles. The inferior
border, thin and sharp, has attached the External intercostal muscle. This border
is marked on its inner side by a deep groove which commences at the tuberosity
and gradually becomes lost at the junction of the anterior with the middle third of
the bone. At the back part of the bone, this groove belongs to the inferior border;
but just in front of the angle, where it is deepest and broadest, it corresponds to
the internal surface; it lodges the intercostal vessels and nerve. Its superior edge
is rounded and continued back as far as the vertebral extremity; it serves for the
attachment of the Internal intercostal muscle. Its inferior edge corresponds to the
lower margin of the rib, and gives attachment to the External intercostal. The
anterior or sternal extremity, is flattened, and presents a porous oval concave
depression, into which the costal cartilage is received.
Peculiar Ribs.
The peculiar ribs which require especial consideration, are five in number, viz.,
the first, second, tenth, eleventh and twelfth.
The^rs^ rib (fig. 64) is one of the shortest and the most curved of all the ribs; it
is broad, flat, and placed horizontally at the upper part of the thorax, its surfaces
looking upwards and downwards; and its borders, inwards and outwards. The
74
OSTEOLOGY.
head is of small size, rounded, and presents only a single articular facet for arti-
culation with the body of the first dorsal vertebra. The neck is narrow and
rounded. The tuberosity, thick and prominent, rests on the outer border,
There is no angle, and it is not twisted on its axis. The upper surface of the
Peculiar Eibs.
ShtfJdla'rmar
^efost 'to tuioe/rosHy
66.
Sitiait, tiTtifCula,T ^meeJt —
67.
Single or tie. fiiee.-
68.
fSi/ngle a/rtie. ftic. — '
shaft is marked towards its anterior part by two shallow depressions, separated
from one another by a ridge, which becomes more prominent towards the internal
border, where it terminates in a tubercle; this tubercle and ridge serve for the
attachment of the Scalenus anticus muscle, the groove in front of it transmitting
the subclavian vein ; that behind it, the subclavian artery. The inferior surface
is smooth, and destitute of the groove observed on the other ribs. The outer
COSTAL CARTILAGES.
75
border is convex, thick, and rounded. The inner, concave, thin, and sharp, and
marlvcd about its centre by the tubercle before mentioned. The anterior extremity
is larger and thicker than any of the other ribs.
The second rib (fig. 65) is much longer than the first, but bears a very considerable
resemblance to it in the direction of its curvature. The non-articular portion of the
tuberosity is occasionally only slightly marked. The angle is slight, and situated
close to the tuberosity, and the rib is not twisted, so that both ends touch any
j^lane surface upon which it may be laid. The shaft is not horizontal, like that of
the first rib; its external surface, which is convex, looking upwards and a little
outwards ; it presents near the middle a rough eminence for the attachment of part
of the first, and the second serration of the serratus magnus. The inner surface
smooth and concave, is directed downwards and a little inwards; it presents a short
groove towards its posterior part.
The tenth rib (fig. 66) has only a single articular surface on its head.
The eleventh and twelfth ribs (figs. 67 and 68) have each a single articular
surface on the head, which is of rather large size; they have no neck or tuberosity,
and are pointed at the extremity. The eleventh has a slight angle and a shallow
groove on the lower border. The twelfth has neither, and is much shorter than
the eleventh.
Structure. The ribs consist of a quantity of cancellous tissue, enclosed in a thin
compact layer.
Development. Each rib, with the exception of the last two, is developed by
three centres, one for the shaft, one for the head, and one for the tubercle. The
last two have only two centres, that for the tubercle being wanting. Ossification
commences in the body of the ribs at a very early period, before its appearance in
the vertebrae. The epiphysis of the head, which is of a slightly angular shape,
and that for the tubercle, of a lenticular form, make their appearance between the
sixteenth and twentieth years, and do not become united to the rest of the bone
until about the twenty-fifth year.
Attachment o^ Muscles. The Intercostals, Scalenus anticus, Scalenus medius.
Scalenus posticus, Pectoralis minor, Serratus magnus, Obliquus externus, Trans-
versalis, Quadratus lumborum, Diaphragm, Latissimus dorsi, Serratus posticus
superioi", Serratus posticus inferior, Sacro-lumbalis, Musculus accessorius ad sacro-
lumbalem, Longissimus dorsi, Cervicalis ascendens, Levatores costarum.
The Costal Cartilages.
The Costal Cartilages (fig. 56) are white elastic structures, which serve to pro-
long the ribs forward to the front of the chest, and contribute very materially
to the elasticity of this cavity. The seven first are connected with the sternum,
the three next with the lower border of the cartilage of the preceding rib. The
cartilages of the two last ribs, which have pointed extremities, float freely in the
parietes of the abdomen. Like the ribs, the costal cartilages vary in their length,
breadth, and direction. They increase in length from the first to the seventh, and
gradually diminish to the last. They diminish in breadth, as well as the intervals
between them, from the first to the last. They are broad at their attachment to the
ribs, and taper towards their sternal extremities, excepting the two first, which
are of the same breadth throughout, and the sixth, seventh, and eighth, which are
enlarged where their margins ax'e in contact. Li direction they also vary; the first
descends a little, the second is horizontal, the third ascends slightly, whilst all the
rest follow the course of the ribs for a short extent, and then ascend to the sternum
or preceding cartilage. Each costal cartilage presents two surfaces, two borders,
and two extremities. The anterior surface is convex, and looks forwards and up-
wards; that of the first gives attachment to the costo-clavicular ligament; that of
the first, second, third, fourth, fifth, and sixth at their sternal ends to the Pectoralis
major. The others are covered, and give partial attachment to some of the
great flat muscles of the abdomen. The posterior surface is concave, and directed
backwards and downwards, the six or seven inferior ones affording attachment
76 OSTEOLOGY.
to the Transversalls and Diaphragm muscles. Of the two borders, the superior is
concave, the inferior, convex; they afford attachment to the Intercostal muscles, the
upper border of the sixth giving attachment to the Pectoralis major muscle. The
contiguous borders also of the sixth, seventh, and eighth, and sometimes the ninth
and tenth costal cartilages present smooth oblong surfaces at the points where they
articulate. Of the two extremities, the outer one is continuous with the osseous
tissue of the rib to which it belongs. The inner extremity of the first is continuous
with the sternum; the six next have rounded extremities, which are received into
shallow concavities on the lateral margins of the sternum. The inner extremities
of the eighth, ninth and tenth costal cartilages are pointed, and lie in contact with
the cartilage above. Those of the eleventh and twelfth are free and pointed.
In the male, the first costal cartilage becomes more or less ossified in the adult,
and is often connected to the sternum by bone. Ossification of the remaining
cartilages also occurs to a variable extent after the middle of life, those of the
true ribs being first ossified. In the female, the process of ossification does not
take place until old age. The costal cartilages are most elastic in youth, those of
the false ribs being more so than the true. In old age they become of a deep
yellow colour.
Attachment of Muscles. The Subclavius, Sterno-thyroid, Pectoralis major,
Internal oblique, Transversalls, Rectus, Diaphragm, Triangularis sterni. Internal
and External intercostals.
THE PELVIS.
The Pelvis is composed of four bones. The two Ossa Innominata, which bound
it in front and at the sides, and the Sacrum and Coccyx, which complete it behind.
The Os InnominaIum.
The Os Innominatum, so called from bearing no resemblance to any known
object, is a large irregular-shaped bone, which, with its fellow of the opposite
side, forms the sides and anterior wall of the pelvic cavity. In young subjects,
it consists of three separate parts, which meet and form the large cup-like cavity,
situated near the middle of the outer side of the bone; and, although in the adult
these have become united, it is usual to describe the bone as divisible into three
portions, the ilium, the ischium, and the pubes.
The ilium is the superior broad and expanded portion which runs upwards
from the upper and back part of the acetabulum, and forms the prominence of the
hip.
The ischium is the inferior and strongest portion of the bone; it proceeds
downwards from the acetabulum, expands into a large tuberosity, and then curving
upwards, forms with the descending ramus of the pubes a large aperture, the
obturator foramen.
The puhes is that portion which runs horizontally inwards from the inner
side of the acetabulum for about two inches, then makes a sudden bend, and
descends to the same extent: it forms the front of the pelvis, and supports the
external organs of generation.
The Ilium presents for examination two surfaces, an external and an internal,
a crest, and two borders, an anterior and a posterior.
External Surface or Dorsum of the Ilium (fig. 69). The back part of this
surface is directed backwards, downwards, and outwards; its front part forwards,
downwards and outwards. It is smooth, convex in front, deeply concave behind;
bounded above by the crest, below by the upper border of the acetabulum, in
front and behind by the anterior and posterior borders. This surface is crossed
in an arched direction by three semicircular lines, the superior, middle, and
inferior curved lines. The superior curved line, the shortest of the three,
commences at the crest, about two inches in front of its posterior extre-
mity; it is at first distinctly marked, but as it passes downwards and out-
wards to the back part of the great sacro-sciatic notch, where it terminates,
it becomes less marked, and is often altogether lost. The rough surface
OS INNOMINATUM.
77
included between this line and the crest, affords attachment to part of the
Gluteus maximus above, a few fibres of the Pyriformis below. The middle curved
line, the longest of the three, commences at the crest, about an inch behind its
69. — Eight Os Innominatum. External Surface.
f
Spine of Fiil'es
^Or/, '*v^fe^5r--^ I \ far Powpart3 ligament
AmgletfPubcs
^"rectos abdominis
ptramidalcs
CESIELLUS IIIfERlOB
anterior extremity, and, taking a curved direction downwards and backwards?
terminates at the upper part of the great sacro-sciatic notch. The space between
the middle, the superior curved lines, and the crest, is concave, and affords attach-
ment to the Gluteus medius muscle. Near the central part of this line may often
be observed the orifice of a nutritious foramen. The inferior curved line,
the least distinct of the three, commences in front at the upper part of the
anterior inferior spinous process, and taking a curved direction backwards and
downwards, terminates at the anterior part of the great sacro-sciatic notch. The
surface of bone included between the middle and inferior curved lines, is concave
from above downwards, convex from before backwards, and affords attachment to
78
OSTEOLOGY.
the Gluteus minimus muscle. Beneath the inferior curved line, and corresponding
to the upper part of the acetabulum, is a smooth eminence (sometimes a depression),
to which is attached the reflected tendon of the Rectus femoris muscle.
The Internal Surface (fig. 70) of the ilium is bounded above by the crest,
70. — Eight Os Innominatum. Internal Surface.
1)^ /'y •
..' "«;<'
l^EVATOR AN!
nPHESSDB OHETHnffi
below by a prominent line, the linea-ileo pectinea, and before and behind by the
anterior and posterior borders. It presents anteriorly a large smooth concave
surface called the internal iliac fossa, or venter of the ilium; it lodges the
Iliacus muscle, and presents at its lower part, the orifice of a nutritious canal.
Behind the iliac fossa is a rough surface, divided into two portions, a superior and
an inferior. The inferior, or auricular portion, so called from its resemblance to the
external ear, is coated with cartilage in the recent state, and articulates with a
similar shaped surface on the side of the sacrum. The superior portion is con-
cave and rough for the attachment of the posterior sacro-iliac ligaments.
The crest of the ilium is convex in its general outline and sinuously curved,
being bent inwards anteriorly, outwards posteriorly. It is longer in the female
OS INNOMINATUM.
79
than in the male, very thick behind, and thinner at the centre than at the
extremities. It terminates at either end in a prominent eminence, the anterior
superior, and posterior superior spinous process. The surface of the crest is
broad, and divided into an external lip, an internal lip, and an intermediate
space. To the external lip is attached the Tensor vaginae femoris, Obliquus
externus abdominis, and Latissimus dorsi, and by its whole length the fascia
lata; to the interspace between the lips, the Internal oblique; to the internal
lip, the Transversalis, Quadratus lumborum, and Erector spinas.
The anterior border of the ilium is concave. It presents two projections
separated by a notch. Of these, the uppermost, formed by the junction of the
crest and anterior border, is called the anterior superior spinous process of
the ilium, the outer border of which gives attachment to the fascia lata, and the
origin of the Tensor vaginae femoris, its inner border, to the Iliacus internus,
whilst its extremity affords attachment to Poupart's ligament and the origin of
the Sartorius. Beneath this eminence, is a notch which gives attachment to the
Sartorius muscle, and across which passes the external cutaneous nerve. Below
the notch is the anterior inferior spinous process, which terminates in the upper
lip of the acetabulum; it gives attachment to the straight tendon of the Rectus
femoris muscle. On the inner side of the anterior inferior spinous process, is a
broad shallow groove, over which passes the Iliacus muscle. The posterior
border, shorter than the anterior, also presents two projections separated by a
notch, the posterior superior, and the posterior inferior spinous processes. The
former corresponds with that portion of the posterior surface of the ilium, which
serves for the attachment of the sacro-iliac ligaments, the latter, to the auricular
portion which articulates with the sacrum. Below the posterior inferior spinous
process, is a deep notch, the great sacro-sciatic.
The Ischium forms the inferior and posterior part of the os innominatum. It
is divisible into a thick and solid portion, the body, and a thin ascending part, the
ramus. The body, somewhat triangular in form, presents three surfaces, an
external, internal, and posterior, and three borders. The external surface cor-
responds to that portion of the acetabulum formed by the ischium; it is smooth
and concave above, and forms a little more than two-fifths of that cavity; its
outer margin is bounded by a prominent rim or lip, to which the cotyloid-fibro-
cartilage is attached. Below the acetabulum, between it and the tuberosity, is a
deep groove, along which the tendon of the Obturator externus muscle runs, as
it passes outwards to be inserted into the digital fossa of the femur. The internal
surface is smooth, concave, and forms the lateral boundary of the true pelvic
cavity; it is broad above, and separated from the venter of the ilium by the linea-
ileo-pectinea, narrow below, its posterior border being encroached upon a little below
its centre, by the spine of the ischium, above and below which are the greater and
lesser sacro-sciatic notches; in front it presents a sharp margin, which forms the
outer boundary of the obturator foramen. This surface is perforated by two or
three large vascular foramina, and affords attachment to part of the Obturator
internus muscle.
The posterior surface is quadrilateral in form, broad and smooth above, narrow
below where it becomes continuous with the tuberosity; it is limited in front by
the margin of the acetabulum, behind by the front part of the great sacro-sciatic
notch. This surface supports the Pyriformis, the two Gremelli, and the Ob-
turator internus muscles, in their passage outwards to the great trochanter.
The body of the ischium presents three borders, posterior, inferior, and
internal. The posterior border presents, a little below the centre, a thin and
pointed triangular eminence, the spine of the ischium, more or less elongated in
different subjects. Its external surface gives attachment to the Oemellus superior,
its internal surface to the Coccygeus and Levator ani, whilst to the pointed extremity
is connected the lesser sacro-sciatic ligament. Above the spine is a notch of large
size, the great sacro-sciatic, converted into a foramen by the lesser sacro-sciatic
ligament; it transmits the Pyriformis muscle, the gluteal vessels and nerve
8o OSTEOLOGY.
passing out above this muscle, the sciatic, nnd internal pndic vessels and nerve,
and a small nerve to the Obturator internus muscle below it. Below the spine is
a smaller notch, the lesser sacro-sciatic; it is smooth, coated with cartilage in the
recent state, the surface of which presents nmnerous markings corresponding to
the subdivisions of the tendon of the Obturator internus which winds over it.
It is converted into a foramen by the sacro-sciatic ligaments, and transmits the
tendon of the Obturator interniis, the nerve which supplies this muscle, and the
pudic vessels and nerve. The inferior border is thick and broad: at its point of
junction with the posterior, is a large rough eminence upon which the body rests
in sittmg; it is called the tuberosity of the ischium. The internal border is thin,
and forms the outer circumference of the obturator foramen.
The tuberosity, situated at the junction of the posterior and inferior borders,
presents for examination an external lip, an internal lip, and an intermediate
space. The external lip gives attachment to the Quadratus femoris and part of
the Adductor magnus muscles. The inner lip is bounded by a sharp ridge for the
attachment of a falciform prolongation of the great sacro-sciatic ligament, pre-
sents a groove on the inner side of this for the lodgment of the internal pudic
vessels and nerve, and more anteriorly has attached the Transversus pei'inei.
Erector penis, and Compressor urethra muscles. The intermediate surface pre-
sents four distinct impressions. Two of these seen at the front part of
the tuberosity ai-e rough, elongated, and separated from each other by a pro-
minent ridge; the outer one gives attachment to the Adductor magnus, the inner
one to the great sacro-sciatic ligament. Two situated at the back part ai'e
smooth, lai'ger in size and separated by an oblique ridge : from the upper and
outer arises the Semi-membranosus; from the lower and inner, the Biceps and
Semi-tendinosus. The most superior part of the tuberosity gives attachment to
the Gemellus inferior.
The ramus is the thin flattened part of the ischium, which ascends from the tube-
rosity upwai'ds and inwards, and joins the ramus of the pubes, their point of junction
being indicated in the adult by a rough eminence. Its outer surface is rough for
the attachment of the Obturator exteruus muscle. Its inner surface forms part of
the anterior wall of the pelvis. Its inner border is thick, rough, slightly everted,
forms part of the outlet of the pelvis, and serves for the attachment of the crus-
peuis. Its outer b-order is thin and sharp, and forms part of the inner margin
of the obturator foramen.
The Pubes forms the anterior part of the os innominatum; it is divisible into a
horizontal ramus or body, and a perpendicular ramus.
The body, or horizontal ramus, presents for examination two extremities, an
outer and an inner, aud four surfaces. The outer extremity, the thickest part of
the bone, forms one-fifth of the cavity of the acetabulum: it presents above, a
rough eminence, the ilio-pectineal, which serves to indicate the point of junction
of the ilium and pubes. The inner extremity of the body of the bone is the
symphysis; it is oval, covered by eight or nine transverse ridges, or a series of
nipple-like processes arranged in rows, separated by grooves; they serve for the
attachment of the interarticular fibro-cartilage, placed between it and the oppo-
site bone. Its upper surface, triangular in form, wider extei'nally than in-
ternally, is bounded behind by a sharp ridge, the pectineal line, or linea-
ilio-pectinea, which, running outwards, marks the brim of the true pelvis. The
surfice of bone in front of the pubic portion of the linea-ilio-pectinea, serves
for the attachment of the Pectineus muscle. This ridge terminates internally
at a tubercle, which projects forwards, and is called the spine of the pubes.
The portion of bone included between the spine and inner extremity of the
pubes is called the crest; it serves for the attachment of the Rectus, Pyrami-
dalis, and conjoined tendon of the Internal oblique and Transversalis. The
point of junction of the crest with the symphysis is called the angle of the pubes.
The inferior surface presents externally a broad and deep oblique groove, for
the passage of the obturator vessels and nerve; and internally a sharp margin,
OS INNOMINATUM.
8i
which forms part of the circumference of the obturator forameTi. Its external
surface is flat and compressed, and serves for t?ie attachment of muscles. Its
internal surface, convex from above downwards, concave from side to side, is
smooth, and forms part of the anterior wall of the pelvis. The descending ramus
of the pubes passes outwards and downwards, becoming thinner and narrower as it
descends, and joins with the ramus of the ischium. Its external surface is rough,
for the attachment of muscles. Its inner surface is smooth. Its inner harder is
thick, rough, and everted, especially in females. In the male it serves for the
attachment of the crus penis. Its outer border forms part of the circumference of
the oVjturator foramen.
The cotyloid cavity or acetabulum, is a deep cup-shaped hemisj)herical depres-
sion; formed internally by the pubes, above by the ilium, behind and below by
the ischium, a little less than two-fifths being formed by the ilium, a little more
than two-fifths by the ischium, and tfie remaining fifth by the pubes. It is
bounded by a prominent uneven rim, which is thick and strong above, and serves
for the attachment of a fibro-cartilaginous structure, which contracts its orifice
and deepens the surface for articulation. It presents on its inner side a deep
notch, the cotyloid notch, which transTnits the nutrient vessels into the interior of
the joint, and is continuous with a deep circular depression at the bottom of the
cavity: this depression is perforated by numerous apertures, lodges a mass of fat,
and its margins serve fV>r the attachment of the ligamentum teres. The notch is
converted, in the natural state, into a foramen by a dense ligamentous band
71. — Plan of the Development of the Os Innominatum.
£y 8 Ce'n.tTc Jt
•3 JcrlTnciry 1 2liu,jn/,lscJtium,ic I^il/bcs \
5. Se candci -ry
'r.TvkC'^
T/ie 3 T-rimury cenires unitf. lhrou€fTi. "YShalittl Jiicee^ahiyutjiu.ltriif
Epiphyses azmear cciaut pabcT^y ^ ^ u,nite. aboLLt 2,0 .. year
which passes across it. Through this foramen the nutrient vessels and nerves
enter the joint.
The obturator or thyroid foramen is a large aperture, situated between the
ischium and pubes. In the male it is large, of an oval form, its longest diameter
being obliquely from above downwards; in the female smaller, and more triangu-
6
82 OSTEOLOGY.
lar. It is bounded by a thin uneven margin, to which a strong membrane is
attached; and presents at its upper and outer part a deep groove, which runs
from the pelvis obliquely forwards, inwards, and downwards. It is converted
into a foramen by the obturator membrane, and transmits the obturator vessels
and nerve.
Structure. This bone consists of much cancellous tissue, especially where it is
thick, enclosed between two layers of thick and dense compact tissue. In the
thinner parts of the bone, as at the bottom of the acetabulum, and centre of the
iliac fossa, it is usually semi-transparent, and composed entirely of compact tissue.
Development {"^g. 'J l). By eight centres: three primary — one for the ilium, one
for the ischium, and one for the pubes; andy?i?e secondary — one for the crest of the
ilium its whole length, one for the anterior inferior spinous process (said to occur
more frequently in the male than the female), one ibr the tuberosity of the ischium,
one for the symphysis pubis (more frequent in the female than the male), and one
for the Y-shaped piece at the bottom of the acetabulum. These various centres
appear in the following order: First, in the ilium, at the lower part of the bone,
immediately above the sciatic notch, at about the same period that the develop-
ment of the vertebrae commences. Secondly, in the body of the ischium, at about
the third month of foetal life. Thirdly, in the body of the pubes, between the
fourth and fifth months. At birth, these centres are quite separate; the crest,
the bottom of the acetabulum, and the rami of the ischium and pubes, being still
cartilaginous. At about the sixth year, the rami of the pubes and ischium are
almost completely ossified. About the thirteenth or fourteenth year, the three
divisions of the bone have extended their growth into the bottom of the acetabu-
lum, being separated from each other by a Y-shaped portion of cartilage, which
now presents traces of ossification. The ilium and ischium then become joined,
and lastly the pubes, through the intervention of the portion above mentioned.
At about the age of puberty, ossific matter appears in each of the remaining por-
tions, and they become joined to the rest of the bone about the twenty-fifth year.
Articulations. With its fellow of the opposite side, the sacrum and femur.
Attachment of Muscles. Ilium. To the outer lip of the crest, the Tensor
vaginae femoris, Obliquus externus abdominis, and Latissimus dorsi; to the internal
lip, the Transversalis, Quadratus lumborum, and Erector spinae; to the interspace
between the lips, the Obliquus internus. To the outer surface of the ilium, the
Gluteus maximus, Gluteus medius. Gluteus minimus, reflected tendon of Rectus,
portion of Pyriformis; to the internal surface, the Iliacus; to the anterior border,
the Sartorius and straight tendon of the Rectus. To the ischium. Its outer
surface, the Obturator externus; internal surface, Obturator internus and Levator
ani. To the spine. The Gemellus superior. Levator ani, and Coccygeus. To
the tuberosity, the Biceps, Semi-tendinosus, Semi-membranosus, Quadratus femoris.
Adductor magnus. Gemellus inferior, Transversus perinasi. Erector penis. To the
pubis, the Obliquus externus, Obliquus internus, Transversalis, Rectus, Pyramida-
lis. Psoas parvus, Pectineus, Adductor longus, Adductor brevis. Gracilis, Obtu-
rator externus and internus. Levator ani. Compressor urethras, and occasionally a
few fibres of the Accelerator urinte.
The Pelvis.
The pelvis is stronger and more massively constructed than either of the other
osseous cavities already considered; it is connected to the lower end of the spine,
which it supports, and transmits its weight to the lower extremities, upon which
it rests. It is composed of four bones — the two ossa innominata, which bound it
on either side and in front; and the sacrum and coccyx, which complete it
behind.
The pelvis is divided by a prominent line, the linea ileo pectinea, into a false
and true pelvis.
The false pelvis is all that expanded portion of the pelvic cavity which is
situated above the linea ileo pectinea. It is bounded on each side by the ossa ilii;
PELVIS. 83
in front it is incomplete, presenting a wide interval between the anterior sunerior
spinous processes of the ilia on either side, filled up in the recent state by the
parietes of the abdomen; behind, in the middle line, is a deep notch. This broad
shallow cavity is admirably adapted to support the intestines, and to transmit part
of their weight to the anterior wall of the abdomen.
The true pelvis is all that part of the pelvic cavity which is situated beneath
the linea ileo pectinea. It is smaller than the false pelvis, but its walls are more
perfect. For convenience of description, it may be divided into a superior cir-
cumference or inlet, an inferior circumfei'ence or outlet, and a cavity.
The superior circumference forms the margin or brim of the pelvis, the
included space being called the inlet. It is formed by the linea ileo pectinea,
completed in front by the spine and crest of the pubes, and behind by the anterior
margin of the base of the sacrum and sacro- vertebral angle.
The i7ilet of the j)elvis is somewhat cordate in form, obtusely pointed in front,
diverging on either side, and encroached upon behind by the projection forwards
of the promontory of the sacrum. It has three principal diameters: antero-poste-
rior (sacro-pubic), transverse, and oblique. The antero-posterior extends from
the sacro-vertebral angle to the symphysis pubis; its average measurement is four
inches. The transverse extends across the greatest width of the pelvis, from the
middle of the brim on one side, to the same point on the opposite; its average
measurement is five inches. The oblique extends from the margin of the pelvis
corresponding to the ileo pectineal eminence on one side, to the sacro-iliac sym-
physis on the opposite side; its average measurement is also five inches.
The cavity of the true pelvis is bounded in front by the symphysis pubis;
behind, by the concavity of the sacrum and coccyx, which, curving forwards
above and below, contracts the inlet and outlet of the canal; and laterally it is
bounded by a broad, smooth, quadrangular plate of bone, corresponding to the
inner surface of the body of the ischium. This cavity is shallow in front, mea-
suring at the symphysis an inch and a half in depth, three inches and a half in
the middle, and four inches and a half posteriorly. From this description, it will
be seen that the cavity of the pelvis is a short, curved canal, considerably deeper
on its posterior than on its anterior wall, and broader in the middle than at either
extremity, from the projection forwards of the sacro-coccygeal column above and
belov/. This cavity contains, in the recent subject, the rectum, bladder, and part
of the organs of generation. The rectum is placed at the back of the pelvis, and
corresponds to the curve of the sacro-coccygeal column, the bladder in front,
behind the symphysis pubis. In the female, the uterus and vagina occupy the
interval between these parts.
The lower circumference of the pelvis is very irregular, and forms what is
called the outlet. It is bounded by three pz'ominent eminences: one posterior,
formed by the point of the coccyx; and one on each side, the tuberosities of the
ischia. These eminences are separated by three notches; one in front, the pubic
arch, formed by the convergence of the rami of the ischia and pubes on each side.
The other notches, one on each side, are formed by the sacrum and coccyx
behind, the ischium in front, and the ilium above: these are called the greater
and lesser sacro-sciatic notches; in the natural state they are converted into
foramina by the lesser and greater sacro-sciatic ligaments.
The diameters of the outlet of the pelvis are two, antero-posterior and trans-
verse. The antero-posterior extends from the tip of the coccyx to the lower part
of the symphysis pubis; and the transverse from the posterior part of one ischiatic
tuberosity, to the same point on the opposite side: the average measurement of
both is four inches. The antero-posterior diameter varies with the length of the
coccyx, and is capable of increase or diminution, on account of the mobility of
this bone.
Position of the Pelvis. In the erect posture, the- pelvis is placed obliquely with
regard to the trunk of the body; the pelvic surface of thesymphysis pubis looking
upwards and backwards, the concavity of the sacrum and coccyx looking down-
G 2
84 OSTEOLOGY.
wards and forwards. The base of the sacrum, in well-formed female bodies,
being nearly four inches above the upper border of the symphysis pubis, and the
apex of the coccyx a little more than half an inch above its lower border. This
obliquity is much greater in the foetus, and at an early period of life, than in the
adult.
Axes of the Pelvis. The plane of the inlet of the true pelvis will be represented
by a line drawn from the base of the sacrum to the upper margin of the symphy-
sis pubis. A line carried at right angles with this at its middle, would correspond
at one extremity with the umbilicus, and by the other with the middle of the
coccyx; the axis of the inlet is therefore directed downwards and backwards.
The axis of the outlet produced upwards, would touch the base of the sacrum;
and is therefore directed downwards and forwards. The axis of the cavity is
curved like the cavity itself: this curve corresponds to the concavity of the
sacrum and coccyx, the extremities being indicated by the central points of the
inlet and outlet.
Differences betioeen the Male and Female Pelvis. In the male, the bones are
heavier, stronger, and more solid, and the muscular impressions and eminences on
their surfaces more strongly marked. It is altogether more massive in its general
form; its cavity is deeper and narrower, and its apertures small. In the female,
the bones are lighter and more delicate, the muscular impressions on its surface
only slightly mai'ked, and the pelvis generally is less massive in structure. The
iliac fossas are large, and the ilia widely expanded; hence the great prominence
of the hips. The cavity is shallow, but capacious, being very broad both in the
antero-posterior and transverse diameters ; the inlet and outlet are also large.
The obturator foramen is triangular ; the tuberosities of the ischia are widely
separated; the sacrum is wider and less curved"; the symphysis pubis not so deep;
and the arch of the pubis is greater, and its edges more everted.
In ili^Q fcBtus, and for several years after birth, the cavity of the pelvis is small;
the viscera peculiar to this cavity in the adult, being situated in the lower part of
the abdomen.
THE UPPER EXTREMITY.
The Upper Extremity consists of four parts — the shoulder, the arm, the fore-
arm, and the hand. The shotdder consists of two bones, the clavicle and the
scapula.
The Clavicle.
The Clavicle {clavis, a ' key '), or collar-bone, is a long bone, curved somewhat
like the italic letter^ and placed horizontally at the upper and lateral part of the
thorax, immediately above the first rib. It articulates internally with the upper
border of the sternum, and with the acromion process of the scapula by its outer
extremity ; serving to sustain the upper extremity in the various positions
which it assumes, whilst at the same time it allows it great latitude of motion.
The horizontal plane of the clavicle is nearly straight; but in the vertical plane it
presents a double curvature, the convexity being in front at the sternal end, and
behind at the scapular end. Its inner two-thirds are of a triangular prismatic
form, and extend, in the natural position of the bone, from the sternum to the
coracoid process of the scapula ; the outer fourth being flattened from above
downwards, and extending from the coracoid process to the acromion. It pre-
sents for examination two surfaces, two borders, and two extremities.
The superior surface (fig, 72), for the inner three-fourths of its extent, is
narrow, smooth, of equal diameter throughout, and presents near the sternal end
impressions for the attachment of the Sterno-mastoid muscle behind, the Pectoralis
major in front. Its outer fourth is broad, flat, uneven, perforated by numerous
foramina, and covered by the fibres of the Deltoid and Trapezius muscles, which
encroach upon it considerably in front and behind.
The inferior surface (fig. 73) is also narrow for the inner three-fourths of its
extent, broader and more flattened externally. Commencing at the sternal extre-
CLAVICLE.
85
mity, may be seen a small facet for artlcvilatlon with the cartilage of the first rib,
continuous with the articular surface at the sternal end of the bone. External to
this a rough impression, the rhomboid, for the attachment of the costo-clavicular
72. — Left Clavicle. Superior Surface.
Av'Tomial JEaety
Ste/malJEai.'bre/mit^j
73. — Left Clavicle. Inferior Surface.
(rhomboid) ligament. The middle third of this surface is occupied by a longitu-
dinal groove, the subclavian groove, broader externally than internally; it gives
attachment to the Subclavius muscle, and by its anterior margin to the strong
aponeurosis which encloses it; internally is a. rough surface, the limit of the attach-
ment of the Pectoralis major below. At the junction of the prismatic with the
flattened portion of the bone, at its posterior border, may be seen a rough eminence,
the tubercle of the clavicle. This, in the natural position of the bone, surmounts
the coracoid process of the scapula, and affords attachment to the conoid ligament.
From this tubercle an oblique line passes forwards and outwards on the under
surface of the acromial extremity. It is called the oblique line of the clavicle, and
affords attachment to the trapezoid ligament.
The anterior border is broad and convex for its sternal half, and presents a
rough impression for the attachment of the Pectoralis major muscle. Its outer half
is a narrow, concave margin, serving for the attachment of the Deltoid: a small
interval is usually left between the attachments of these muscles, where this
border is smooth, receiving no muscular fibres. This is the narrowest part of the
clavicle, and hence the most common seat of fracture.
The posterior border is broad and deeply concave for the inner two-thirds of
its extent, affording attachment internally by a small extent of surface, to the
Sterno-hyoid; convex, narrow, and irregular in its outer third, for the attachment
of the Trapezius. This border corresponds to the subclavian vessels and brachial
plexus of nerves, and presents, towards its centre, the foramen for the nutritious
artery of the bone.
The internal or sternal end of the clavicle is directed inwards, and a little
downwards and forwards ; it presents a large triangular facet, concave from before
backwards, convex from above downwards, which articulates with the sternum
through the intervention of an inter-articular fibro-cartilage; the circumference
of the articular surface is rough, for the attachment of numerous ligaments.
86 OSTEOLOGY.
The outer extremity, directed forwards and outwards, presents a small oval
facet, for articulation with the acromion process of the scapula.
Peculiarities of this Bone in the Sexes and in Individuals. In the female, the
clavicle is less curved, smoother, longer, and more slender than in the male. In
those persons who perform considerable manual labour, which brings into constant
action the muscles connected with this bone, it acquires considerable bulk, becomes
shorter, more curved, its ridges for muscular attachment become prominently
marked, and its sternal end of a prismatic or quadrangular form.
Structure. The shaft as well as the extremities consists of cancellous tissue,
invested in a compact layer much thicker in the centre than at either end. The
clavicle is highly elastic, by reason of its curves. From the experiments of Mr.
Ward, it has been shewn that it possesses sufficient longitudinal elastic force to
raise its own weight nearly two feet on a level surface; and sufficient transverse
elastic force, opposite the centre of its anterior convexity, to raise its own weight
about a foot. This extent of elastic power must serve to moderate very consider-
ably the effect of concussions received upon the point of the shoulder.
Development. By two centres: one for the shaft, and one for the sternal end
of the bone. The centre for the shaft appears very early, before any other bone;
the second centre makes its appearance about the eighteenth or twentieth year,
and unites with the rest of the bone a few years after.
Articulations. With the sternum, scapula, and cartilage of the first rib.
Attachment of Muscles. The Sterno cleido-mastoid. Trapezius, Pectoralis major,
Deltoid, Subclavius, and Sterno-hyoid.
The Scapula.
The Scapula is a large flat bone, triangular in shape, which forms the back part
of the shoulder. It is situated at the posterior aspect and side of the thorax,
between the first and seventh ribs, and presents for examination two surfaces, three
borders, and three angles.
The anterior surface, or venter (fig. 74), presents a broad concavity, the sub-
scapular fossa. It is marked, in the posterior two thirds, by several oblique ridges,
which pass from behind obliquely forwards and upwards, the anterior third being
smooth. The oblique ridges above-mentioned, give attachment to the tendinous
intersections, and the surfaces between them, to the fleshy fibres of the Subscapu-
laris muscle. The anterior third of the fossa, which is smooth, is covered by,
but does not afford attachment to, the fibres of this muscle. This surface is sepa-
rated from the posterior border, by a smooth triangular margin at the superior and
inferior angles, and in the interval between these, by a narrow margin which is
often deficient. This marginal surface affords attachment throughout its entire
extent to the Serratus magnus muscle. The subscapular fossa presents a trans-
verse depression at its upper part, called the subscapular angle; it is in this situ-
ation that the fossa is deepest, and consequently the thickest part of the Subscapularis
muscle lies in a line parallel with the glenoid cavity, and must consequently operate
most effectively on the humerus which is contained in it.
The posterior surface, or dorsum (fig, 75) is convex from above downwards,
alternately convex and concave from side to side. It is subdivided unequally into
two parts by the spine; that portion above the spine is called the supra spinous
fossa, and that below it, the infra spinous fossa.
The supra spinous fossa, the smaller of the two, is concave, smooth, and broader
towards the vertebral than at the humeral extremity. It affords attachment by its
inner two-thirds to the fibres of the Supra spinatus muscle.
The infra spinous fossa is much larger than the preceding; towards its inner
side a shallow concavity is seen at its upper part; its centre presents a prominent
convexity, whilst towards the axillary border is a deep groove, which runs from
the upper towards the lower part. The inner three-fourths of this surface affords
attachment to the Infi-a-spinatus muscle; the outer fourth is only covered by it,
without giving origin to its fibres. This surface is separated from the axillary
SCAPULA.
«7
border by an elevated ridge, which runs from the lower part of the glenoid cavity,
downwards and backwards to the posterior border, about an inch above the infe-
rior angle. This ridge serves for the attachment of a strong aponeurosis, which
separates the Infra-spinatus from the two Teres muscles. The surface of bone
between this line and the axillary border is narrow for the upper two-thirds of its
extent, and traversed near its centre by a groove for the passage of the dorsalis
6capula3 artery; it affords attachment to the Teres minor. Its lower third presents
a broader, somewhat triangular surface, which gives origin to the Teres major, and
74. — Left Scapiila. Anterior Surface, or Venter.
over which glides the Latissimus dorsi muscle; sometimes this muscle takes origin
by a few fibres from this part. The broad and narrow portions of bone above
alluded to are separated by an oblique line, which runs from the axillary border,
downwards and backwards; to it is attached the aponeurosis separating the two
Teres muscles from each other.
Ihe Spine ia a prominent plate of bone, which crosses obliquely the inner
three-fourths of the dorsum of the scapula at its upper part, and separates
OSTEOLOGY.
the supra from the infra spinous fossa: it commences at the vertebral border by
a smooth triangular surface, oyerwhicli the trapezius glides, separated by a bursa;
and, gi-adually becoming more elevated as it passes forwards, terminates in the
acromion process which overhangs the shoulder joint. The spine is triangular and
flattened from above downwards, its apex corresponding to the posterior border, its
base, which is directed outwards, to the neck of the scapula. It presents two
75. — Left Scapula. Posterior Surface, or Dorsum.
00^J>J
^^oo^'^
fiVlOf,
W>^
surfaces and three borders. Its superior surface is concave, assists in forming the
supra-spinous fossa, and alFords attachment to part of the Supra-spinatus muscle.
Its inferior surface forms part of the infra-spinous fossa, gives origin to part of the
Infra-spinatus muscle, and presents near its centre the orifice of a nutritious canal.
Of the three borders, the anterior is attached to the dorsum of the bone; the
posterior, or crest of the spine, is broad, and presents two lips^ and an intervening
SCAPULA. 89
roui^h interval. To the superior lip is attached the Trapezius, to the extent shown
in the figure. A very rough prominence is generally seen occupying that portion
of the spine which receives the insertion of the middle and inferior fibres of this
muscle. To the inferior lip, its whole length, is attached the Deltoid. The interval
between them is also partly covered by the fibres of these muscles. The external
border, the shortest of the three, is slightly concave, its edges thick and round,
continuous above with the under surface of the acromion, process, below with the
neck of the scapula. The narrow portion of bone external to this border, serves
to connect the supra and infra spinous fosste.
The Acromion process, so called from forming the summit of the shoulder joint
{aKpov, a summit; w/xo?, the shoulder), is a large, and somewhat triangular process,
flattened from behind forwards, directed at first a little outwards, and then curving
forwards and upwards, so as to overhang the glenoid cavity. Its upper surface
directed upwards, backwards, and outwards, is convex, rough, and partly covered
by some of the fibres of origin of the Deltoid. Its under surface is smooth and con-
cave. Its outer border, which is thick and irregular, affords attachment to the
Deltoid muscle. Its inner margin, shorter than the outer, is concave, gives attach-
ment to a portion of the Trapezius muscle, and presents about its centre a small
oval surface, for articulation with the scapular end of the clavicle. Its apex,
formed at the point of meeting of these two borders in front, is thin, and has
attached to it the coraco-acromion ligament.
Of the three borders or costge of the scapula, the superior is the shortest and
thinnest; it is concave, terminating at its inner extremity at the superior angle,
at its outer extremity at the coracoid process. At its outer part is a deep
semicircular notch, formed partly by the base of the coracoid process. This notch
is converted into a foramen by the transverse ligament, and serves for the passage
of the supra scapular nerve. The adjacent margin of the superior border affords
attachment to the Omo-hyoid muscle. The external, or axillary border, is the
thickest of the three. It commences above at the lower margin of the glenoid cavity,
and inclines obliquely downwards and backwards to the inferior angle. Imme-
diately below the glenoid cavity, is a rough depression about an inch in length,
which affords attachment to the long head of the Triceps muscle; to this succeeds
a longitudinal groove which extends as far as its lower third, and affords origin to
part of the Subscapularis muscle. The inferior third of this border which is thin
and sharp, serves for the attachment of a few fibres of the Teres major behind, and
of the Subscapularis in front. The internal, or vertebral border, also named the
base, is the longest of the three, and extends from the superior to the inferior
angle of the bone. It is convex, intermediate in thickness between the superior
and the external, and that portion of it above the spine bent considerably outwards,
so as to form an obtuse angle with the lower part. This border presents an ante-
rior lip, a posterior lip, and an intermediate space. The anterior lip affords
attachment to the Serratusmagnus; ihe posterior lip, to the Supra-spinatus above
the spine, the Infra- spinatus below; the interval between the two lips, to the Leva-
tor anguli scapulee above the triangular surface at the commencement of the spine,
the Rhomboideus minor, to the edge of that surface; the Rhomboideus major being
attached by means of a fibrous arch, connected above to the lower part of the
triangular surface at the base of the spine, and below to the lower part of the pos-
terior border.
Of the three angles, the superior, formed by the junction of the superior and
internal borders, is thin, smooth, rounded, somewhat inclined outwards, and gives
attachment to a few fibres of the Levator anguli scapulae muscle. The inferior
angle thick and rough, is formed by the union of the vertebral and axillary
borders, its outer surface affording attachment to the Teres major, and occasionally
a few fibres of the Latissimus dorsi. The anterior angle is the thickest part of
the bone, and forms what is called the head of th.e scapula. The head presents
a shallow, pyriform, articular surface, the glenoid cavity {'yXrjvrj, a superficial
cavity; etSo?, like); its longest diameter is from above downwards, and its
90
OSTEOLOGY.
direction outwards and forwards. It is broader below than above; at its apex
is attached the long tendon of the Biceps muscle. It is covered with cartilage in the
recent state; and its margins, slightly raised, give attachment to a fibro-cartilaginous
structure, the glenoid ligament, by which its cavity is deepened. The neck of
the scapula is the slightly depressed surface which surrounds the head, it is more
distinct on the posterior than on the anterior surface, and below than above. In
the latter situation, it has, arising from it, a thick prominence, the coracoid
process.
The Coracoid process, so called from its fancied resemblance to a crow's beak
{Kopa^, a crow; eiSo?, like), is a thick curved process of bone, which arises by a
broad base from the upper part of the neck of the scapula; it ascends at first
upwards and inwards, then becoming smaller, it changes its direction and passes
forwards and outwards. The ascending portion, flattened from before backwards,
presents in front a smooth concave surface, over which passes the sub-scapularis
muscle. The horizontal portion is flattened from above downwards; its upper
surface is convex and irregular; its under surface is smooth; its anterior border
is rough, and., gives attachment to the Pectoralis minor, its posterior also rough
to the coraco-acromion ligament, while the apex is embraced by the conjoined
tendon of origin of the short head of the Biceps and Coraco-brachialis muscles.
At the inner side of the root of the coracoid process is a rough depression for the
attachment of the conoid ligament, and running from it obliquely forwards and
outwards on the upper surface of the horizontal portion, an elevated ridge for
the attachment of the trapezoid ligament.
Structure. In the head, processes, and all the thickened parts of the bone, it
is cellular in structure, of a dense compact tissue in the rest of its extent. The
76. — Plan of the Development of the Scapula. By Seven Centres.
^S°^C,
Vi^no-^
Epiphyses (except one for the Coracoid process) appear at fifteen to
seventeen years, and unite at twenty-two to twenty-five years.
iiump:rus.
91
centre and upper part of the dorsum, but especially the former, is usually so thin
as to be semi-transparent; occasionally the bone is found wanting in this situ-
ation, and the adjacent muscles come into contact.
Development {^g. 76). By seven centres; one for the body, two for the coracoid
process, two for the acromion, one for the posterior border, and one for the inferior
angle.
That for the body makes its first appearance at about the same period that
osseous matter is deposited in the vertebras, and forms the chief part of the bone.
At birth, all the other centres are cartilaginous. About the first year after birth,
osseous deposition occurs in the middle of the coracoid process; which usually
becomes joined with the rest of the bone at the time when the other centres make
their appearance. Between the fifteenth and seventeenth years, osseous matter is
deposited in the remaining centres in quick succession, and in the following order:
first, near the base of the acromion, and in the upper part of the coracoid process,
the latter appearing in the form of a broad scale; secondly, in the inferior angle
and contiguous part of the posterior border; thirdly, near the extremity of the
acromion; fourthly, in the posterior border. The acromion process, besides being
formed of two separate nuclei, has its base formed by an extension into it of the
centre of ossification which belongs to the spine, the extent of which varies in
different cases. The two separate nuclei unite, and then join with the extension
carried in from the spine. These various epiphyses become united to the bone
between the ages of twenty-two and twenty-five years.
Articulations. With the humerus and clavicle.
Attachment of Muscles. To the anterior surface, the Subscapularis; posterior
surface, Supra-spinatus, Infra-spinatus; spine. Trapezius, Deltoid; superior
border, Omo-hyoid; vertebral border, Serratus magnus, Levator anguli scapulas,
Rhomboideus minor and Major; axillary border. Triceps, Teres minor. Teres
major,' glenoid cavity; long head of the Biceps, coracoid process; short head of
Biceps, Coraco-brachialis, Pectoralis minor; and to the inferior angle occasionally
a few fibres of the Latissimus dorsi.
The Humerus.
The Humerus is the longest and largest bone of the upper extremity; it pre-
sents for examination a shaft and two extremities.
The Superior Extremity is the largest part of the bone; it presents a rounded
head, a constriction around the base of the head, the neck, and two other emi-
nences, the greater and lesser tuberosities (fig. 77).
The head, nearly hemispherical in form, is directed inwards, upwards, and a
little backwards; its surface is smooth, coated with cartilage in the recent state,
and articulates with the glenoid cavity of the scapula. The circumference of its
articular surface is slightly constricted, and is termed the anatomical neck, in
contradistinction to the constriction which exists below the tuberosities, and
is called the surgical neck, from its being the seat of the accident called by
surgeons, 'fracture of the neck of the humerus.'
The neck, which is obliquely directed, forming an obtuse angle with the shaft,
is more distinctly marked in the lower half of its circumference, than in the
upper half, where it presents a narrow groove, separating the head from the
tuberosities. Its circumference afibrds attachment to the capsular ligament, and
is perforated by numerous vascular foramina.
The greater tuberosity is situated on the outer side of the head and lesser
tuberosity. Its superior surface is rounded and marked by three flat facets,
separated by two slight ridges, the most anterior giving attachment to the
tendon of the Supra-spinatus; the middle, to the Infra-spinatus; the posterior, to
the Teres minor. The external surface of the great tuberosity is convex, rough,
and continuous with the outer side of the shaft.
The lesser tuberosity is more prominent, although smaller than the greater;
it is situated in front of the head, and is directed inwards and forwards. Its
92
OSTEOLOGY.
77. — Left Humerus. Anterior View.
ComTtion Origin
SUPINATOR RADII LONCUS
FLEXOR CARPI RA0IALI8
PALMARIS LONCUS <
rLE.XOR DJCITORUM SUBLIMIS
,, CARPI ULNARIS
EXTENSOR CARPI RADIALI.S
LONCIOR
t ^
V EXTENSOR. CARP.RAD. GREV
„ DIOITQRUM COMMUfviiS
., MIIMIMI DICITI
„ CARPI UIWARIS
SUPIWATOR BREVIS
HUMERUS.
93
summit presents a pi'ominent facet for the insertion of the tendon of the Subsca-
pularis muscle. These two tuberosities are separated from one another by a
deep groove, the bicipital groove, so called from its lodging the long tendon of the
Biceps muscle. It commences above between the two tuberosities, passes obliquely-
down wards and a little inwards, and terminates at the junction of the upper with
the middle third of the bone. It is deep and narrow at its commencement, and
becomes shallow and a little broader as it descends. In the recent state it is
covered with a thin layer of cartilage, lined by a prolongation of the synovial
membrane of the shoulder joint, and receives part of the tendon of insertion of
the Latissimus dorsi about its centre.
The Shaft of the humerus is almost cylindrical in the upper half of its extent;
prismatic and flattened below, it presents three borders and three surfaces for
examination.
The external border runs from the back part of the greater tuberosity to
the external condyle, and separates the external from the posterior surface. It is
rounded and indistinctly marked in its upper half, and serves for the attachment
of the external head of the triceps muscle; its centre is traversed by a broad but
shallow oblique depression, the musculo-spiral groove ; its lower part is marked
by a prominent rough margin, a little curved from behind forwards, which presents
an anterior lip for the attachment of the Supinator longus above, the Extensor carpi
radialis longior below, a posterior lip for the Triceps, and an interstice for the
attachment of the external intermuscular aponeurosis.
The internal border extends from the lesser tuberosity above to the internal
condyle below. Its upper third is marked by a prominent ridge, forming the
inner lip of the bicipital groove, and giving attachment from above downwards
to the tendons of the Latissimus dorsi, Teres major, and part of the origin of the
inner head of the Triceps. About its centre is a rough ridge for the attachment
of the Coraco-brachialis, and just below this is seen the entrance of the nutritious
canal directed downwards. Its inferior third is raised into a slight ridge, which
becomes very prominent below; it presents an anterior lip for the attachment of
the Brachialis anticus, a posterior lip for the internal head of the Triceps, and an
intermediate space for the internal intermuscular aponeurosis.
The anterior border runs from the front of the great tuberosity above, to the
coronoid depression below, separating the internal from the external surface. Its
upper part is very prominent and rough, forms the outer lip of the bicipital groove,
and serves for the attachment of the tendon of the Pectoralis major. About its
centre is seen the rough deltoid impression; below, it is smooth and rounded,
affording attachment to the Brachialis anticus.
The external surface is directed outwards above, where it is smooth, rounded,
and covered by the Deltoid muscle; forwards below, where it is slightly concave
from above downwards, and gives origin to part of the Brachialis anticus muscle.
About the middle of this surface, is seen a rough triangular impression for the
insertion of the Deltoid muscle, and below it the musculo-spiral groove, directed
obliquely from behind, forwards and downwards; it transmits the musculo-spiral
nerve and superior profunda artery.
The internal surface, less extensive than the external, is directed forwards
above, inwards and forwards below: at its upper part it is narrow, and forms the
bicipital groove. The middle part of this surface is slightly rough for the
attachment of the Coraco-brachialis; its lower part is smooth, concave, and
gives attachment to the Brachialis anticus muscle.
The posterior surface (fig. 78) appears somewhat twisted, so that its superior
part is directed a little inwards, its inferior part backwards and a little outwards.
Nearly the whole of this surface is covered by the external and internal heads of
the triceps, the former being attached to its upper and outer part, the latter to its
inner and back part, their origin being separated by the musculo-spiral groove.
The Loxoer Extremity is flattened from before backwards, and curved slightly
forwards; it terminates below in a broad articular surface, which is divided into
94
OSTEOLOGY.
78. — Left Humerus. Posterior surface.
.INFRA ^
)1
¥A
f
n
^^
\Trochl\
two parts by a shallow groove; on either
side of the articulate surface are the ex-
ternal and internal condyles. The articular
surface extends a little lower than the con-
dyles, and is curved slightly forwards, so
as to occupy the more anterior part of the
bone; its greatest breadth is in the trans-
verse diameter, and it is obliquely directed,
so that its inner extremity occupies a lower
level than the outer. The outer portion
of this articular surface presents a smooth
rounded eminence, which has received the
name of the lesser or radial head of the
humerus; it articulates with the cup-shaped
depression on the head of the radius, is
limited to the front and lower part of the
bone, and does not extend as far back as
the other portion of the articular surface.
On the inner side of this eminence is a
shallow groove, in which is received the
inner margin of the cup-like cavity of the
head of the radius. The inner or trochlear
portion of the articular surface pi*esents
a deep depression between two well-
markeL borders. This surface is curved
from before backwards, concave from side
to side, and occupies the anterior lower and
posterior part of the bone. The external
border, less prominent than the internal,
corresponds to the interval between the
radius and ulnar. The internal border is
thicker, more prominent, and, consequently,
of greater length than the external. The
grooved portion of the articular surface fits
accurately within the greater sigmoid cavity
of the ulna; it is broader and deeper on the
posterior than on the anterior aspect of
the bone, and is directed obliquely from
behind forwards, and from without inwards.
Lnmediately above the back part of the
trochlear surface, is a deep triangular de-
pi'ession, the olecranon depression, in which
is received the summit of the olecranon
process in extension of the fore-arm. Above
the front part of the trochlear surface, is
seen. a smaller depression, the coronoid de-
pression; it receives the coronoid process
of the ulna during flexion of the fore-arm.
These fossss are separated from one another
by a thin lamina of bone, which is some-
times perforated; their margins afford at-
tachment to the anterior and posterior
ligaments of the elbow joint, and they are
lined in the recent state by the synovial
membrane of this articulation. Above the
front part of the radial tuberosity, is seen
a slight depression which receives the
HUMERUS.
95
anterior border of the head of the radius when the fore-arm is strongly flexed.
The external condyle is a small tubercular eminence, less prominent than the
internal, curved a little forwards, and giving attachment to the external lateral
ligament of the elbow joint, and to a tendon common to the origin of some of the
extensor and supinator muscles. The internal condyle, larger and more promi-
nent than the external, is directed a little backwards, it gives attachment to the
internal lateral ligament, and to a tendon common to the origin of some of the flexor
muscles of the fore-arm. These eminences are directly continuous above with the
external and internal borders.
Structure. The extremities consist of cancellous tissue, covered with a thin
compact layer; the shaft is composed of a cylinder of compact tissue, thicker at
the centre than at the extremities, and hollowed out by a large medullary canal.
Development. By seven centres
79.-
Plan of the Development of the Humerus.
By 7 centres.
EpijjJiyses efHead & | A.*^
Tiiierosities ileniZ a^ I ty
S.yV and umte |
wBh Skafl at 20 *}■;/ Tj
seven
(fig. 79); one for the shaft, one for
the head, one for the greater tu-
berosity, one for the radial, and one
for the trochlear portion of the
articular surface, and one for each
condyle. The centre for the shaft ap-
pears very early, soon after ossifica-
tion has commenced in the cavicle,
and soon extends towards the extremi-
ties. At birth, it is ossified nearly in
its whole length, the extremities re-
maining cartilaginous. Between the
first and second years, ossification com-
mences in the head of the bone, and
between the second and third years
the centre for the tuberosities marks
its appearance usually by a single
ossific point, but sometimes, according
to Beclard, by one for each tuberosity,
that for the lesser being Small, and not
appearing until after the fourth year.
By the fifth year, the centres for the
head and tuberosities have enlarged
and become joined, so as to form a
single large epiphysis.
The lower end of the humerus is
developed in the following manner:
At the end of the second year, ossifi-
cation commences in the radial portion
of the articular surface, and from this point extends inwards, so as to form the
chief part of the articular end of the bone, the centre for the inner part of
the articular surface not appearing until about the age of twelve. Ossification
commences in the internal condyle about the fifth year, and in the external one
not until between the age of thirteen or fourteen. About sixteen or seventeen
years, the outer condyle and both portions of the articulating surface (having
already joined) unite with the shaft; at eighteen years, the inner condyle becomes
joined, whilst the upper epiphysis, although the first formed, is not joined until
about the twentieth year.
Articulations. With the glenoid cavity of the scapula,and with the ulna and radius.
Attachment of Muscles. To the greater tuberosity, the Supra-spinatus, Infra-
spinatus, and Tei-es minor; to the lesser tuberosity, the Subscapularis; to the ante-
rior bicipital ridge, the Pectoralis major; to the posterior bicipital ridge and groove,
the Latissimus dorsi and Teres major; to the shaft, the Deltoid, Coraco-brachialis,
Brachialia anticus. External and Internal heads of the Triceps; to the internal
Jhiites wr.
Shajta
96
OSTEOLOGY.
80. — Bones of the Left Fore-Arm. Anterior Surface.
RADIUS
FLEXOR DICITORUM
SUBLIMIS
PRDN ATOR
RADII, TERES
of FLEXOR LONCUS POLLICIS
"f
FLEXOR DICITORUM
SUBLIM IS
Styloid JBrocess
SUPINATOR LOMCUS
Groove Jar ext. qssis
METACARPI POLLieiS
GroovafanEtS. PRIMI
INTERNODII POLLICIS
ULNA.
97
condyle, the Pronator radii teres, and common tendon of the Flexor carpi radialis,
Palmaris longus, Flexor digitorum sublimis, and Flexor carpi ulnaris ; to the
external condyloid ridge, the Supinator longus, and Extensor carpi radialis
longior; to the external condyle, the common tendon of the Extensor carpi
radialis brevior. Extensor communis digitorum. Extensor minimi digiti, and Ex-
tensor carpi ulnaris, the Anconeus, and Supinator brevis.
The Fore-arm is that portion of the upper extremity, situated between the
elbow and wrist. It is composed of two bones, the Ulna and Eadius.
The Ulna,
The Ulna (fig. 80, 8 1) is a long bone, prismatic in form, placed at the inner side
of the fore-arm, parallel with the radius, being the largest and longest of the two.
Its upper extremity, of great thickness and strength, forms a large part of the
articulation of the elbow joint; it gradually tapers as it descends, its inferior
extremity being very small, and excluded from the wrist joint by the interposi-
tion of an interarticular fibro-cartilage. It is divisible into a shaft and two
extremities.
The Upper Extremity, the strongest part of the bone, presents for examination
two large curved processes, the Olecranon process and the Coronoid process, and
two concave articular cavities, the greater and lesser Sigmoid cavities.
The Olecranon Process is a large thick curved eminence, situated at the upper
and back part of the ulna. It rises somewhat higher than the coronoid, is
contracted where it joins the shaft, and curved forwards at the summit so as to
present a prominent tip. Its posterior surface, directed backwards, is of a
triangular form, smooth, subcutaneous, and covered by a bursa. Its superior
surface, directed upwards, is of a quadrilateral form, marked behind by a rough
surface for the attachment of the Triceps muscle, and in front, near the margin,
by a slight transverse groove for the attachment of part of the posterior ligament
of the elbow joint. Its anterior surface is smooth, concave, covered with car-
tilage in the recent state, and forms the upper and back part of the great sigmoid
cavity. The lateral borders present a continuation of the same groove that was
seen on the margin of the superior surface, they serve for the attachment of
ligaments, viz., the back part of the internal lateral ligament internally; the
posterior ligament externally. The Olecranon process, in its structure as well
as in its position and use, resembles the Patella in the lower limb, and, like it,
sometimes exists as a separate piece, not united to the rest of the bone.
The Coronoid Process {Kopcovrj, a crow's beak; etSo?) is a rough triangular
eminence of bone which projects horizontally forwards from the upper and front
part of the ulna, forming the lower part of the great sigmoid cavity. Its base
is continuous with the shaft. Its apex, pointed, slightly curved upwards, is
received into the coronoid depression of the humerus in flexion of the fore-arm.
Its superior surface is smooth, concave, and forms the lower part of the great
sigmoid cavity. The inferior surface is concave, directed downwards and for-
wards and marked internally by a rough impression for the insertion of the Bra-
chialis anticus. At the junction of this surface with the body, is a rough eminence,
the tubercle of the ulna, for the attachment of the oblique ligament. Its outer
surface presents a narrow, oblong, articular depression, the lesser sigmoid cavity.
The inner surface, by its prominent free margin, serves for the attachment of the
front part of the internal lateral ligament. At the front part of this surface is a small
rounded eminence for the attachment of one head of the Flexor digitorum sublimis.
Behind the eminence, a depression for part of the origin of the Flexor profundus
digitorum, and descending from it a ridge, lost below on the inner border of the
shaft, which gives attachment to one head of the Pronator radii teres.
The Greater Sigmoid Cavity {ai^ixa, €iSo<;, form), so called from its resemblance
to the Greek letter S, is a semi-lunar depression of large size, situated between
the olecranon and coronoid processes, and serving for articulation with the trochlear
surface of the humerus. About the middle of either lateral border of this cavity
98 OSTEOLOGY.
is a notch, which contracts it somewhat, and serves to indicate the junction of the
two processes of which it is formed. The cavity is concave from above down-
wards, and divided into two lateral parts by a smooth elevated ridge, which runs
from the summit of the olecranon to the tip of the coronoid process. Of these two
portions, the intei'nal is the largest, and slightly concave transversely; the external
the smallest, being nearly plane from side to side.
The Lesser Sigmoid Cavity is a narrow, oblong, articular depression, placed on
the outer side of the coronoid process, and serving for articulation with the head
of the radius. It is concave from before backwards ; and its extremities, which are
prominent, serve for the attachment of the orbicular ligament.
The Shaft is prismatic in form at its upper part, and curved from behind
forwards, and from within outwards, so as to , be convex behind and exter-
nally; its central part is quite straight; its lower part rounded, smooth, and bent
a little outwards; it tapers gradually from above downwards, and presents for
examination three borders and three surfaces.
The anterior border commences above at the prominent inner angle of the
coronoid process, and terminates below in front of the styloid process. It is well
marked above, smooth and rounded in the middle of its extent, and affords attach-
ment to the Flexor profundus digitorum, sharp and prominent in its lower fourth
for the attachment of the Pronator quadratus. It separates the anterior from the
internal surface.
The posterior border commences above at the apex of the triangular surface at
the back part of the olecranon, and terminates below at the back part of the sty-
loid process; it is well marked in the upper three-fourths, and gives attachment to
an aponeurosis common to the Flexor carpi ulnaris, the Extensor carpi ulnaris, and
the Flexor profundus digitorum muscles; its lower fourth is smooth and rounded.
This border separates the internal from the posterior surface.
The external border commences above by two lines, which converge one from
each extremity of the lesser sigmoid cavity, enclosing between them a triangular
space for the attachment of part of the Supinator brevis, and terminates below at
the middle of the articular surface for the radius. Its two middle-fourths are
very prominent, and serve for the attachment of the interosseous membrane; its
lower fourth is smooth and rounded. This border separates the anterior from the
posterior surface.
The anterior surface, much broader above than below, is concave in the upper
three-fourths of its extent, and affords attachment to the Flexor profundus digito-
rum. Its lower fourth, also concave, to the Pronator quadratus. The lower fourth
is separated from the remaining portion of the bone by a prominent ridge, directed
obliquely from above downwards and inwards; this ridge marks the extent of
attachment of the Pronator above. At the junction of the upper with the middle
third of the bone is the nutritious canal, directed obliquely upwards and inwards.
The posterior surface, directed backwards and outwards, is broad and concave
above, somewhat narrower and convex in the middle of its course, narrow, smooth,
and rounded below. It presents above an oblique ridge, which runs from the pos-
terior extremity of the lesser sigmoid cavity, downwards to the posterior border,
marking off a small triangular surface above it for the insertion of the Anconeus
muscle, whilst the ridge itself affords attachment to the Supinator brevis. The
surface of bone below this is subdivided by a longitudinal ridge into two parts,
the internal part is smooth, concave, and gives origin (occasionally is merely covered
by) the Extensor carpi ulnaris. The external portion, wider and rougher, gives
attachment from above downwards to part of the Supinator brevis, the Extensor
ossis metacarpi pollicis. Extensor secundii internodii pollicis, and Extensor indicis
muscles.
The internal surface is broad and concave above, narrow and convex below.
It gives attachment by its upper three-fourths to the Flexor profundus digitorum
muscle; its lower fourth is subcutaneous.
The Lower Extremity of the ulna is of small size, and excluded from the articu-
lation of the wrist joint. It presents for examination two eminences; the outer
ULNA.
!i. — Bones of the Left Forearm. Posterior Surface.
ULNA
RADIUS
99
yI?7*EX.T.CARPI RAD. to
EXT. CARPI RAD.BiLi
EXT. SECUNDl INTERNODII POLLICl's
LGXOK DICITORUM
'SUBLIMIS'
EXT. CARPI ULNAS
EXT. INDICIS
EXT. DICITORUM COMMUNIS
EXT. MIIMimi DICITI
100
OSTEOLOGY.
and larger is a rounded articular eminence, termed the head of the ulna. The
inner, narrower and more projecting, is a non-articular eminence, the styloid
process. The head presents an articular facet, part of which, of an oval form, is
directed downwards, and plays on the surface of the triangular fibro-cartilage,
which separates this bone from the wrist joint; the remaining portion, directed
outwards, is narrow, convex, and received into the sigmoid cavity of the radius.
The styloid process projects from the inner and back part of the bone, and descends
a little lower than the head, terminating in a rounded summit, which affords attach-
ment to the internal lateral ligament of the wrist. The head is separated from
the styloid process below and in front, by a depression for the attachment of the
triangular inter-articular fibro-cartilage; behind, by a shallow groove for the pas-
sage of the tendon of the Extensor carpi ulnaris..
Structure. Similar to that of the other long bones.
Development. By three centres; one for the shaft, one for the inferior extremity,
and one for the olecranon (fig. 82). The centre for the shaft appears a short time after
the radius, and soon extends through the greater part of the bone. At birth, the
ends are cartilaginous. About the fourth year, a separate osseous nucleus appears
in the middle of the head, which soon 82.— Plan of the Development of the Ulna.
By Three Centres.
extends into the styloid process.
About the tenth year, ossific matter
appears in the upper cartilaginous end
of the bone near its extremity, the
chief part of the olecranon being
formed from an extension of the
shaft of the bone into it. At about
the sixteenth year, the upper epiphysis
becomes joined, and at about the twen-
tieth the inferior one.
Articulations. With the humerus
and radius.
Attachment of Muscles. To the
olecranon; the Triceps, Anconeus, and
one head of the Flexor carpi ulnaris.
To the coronoid process; the Bra-
chialis anticus. Pronator radii teres,
Flexor sublimis digitorum, and Flexor
profundus digitorum. To the shaft;
the Flexor profundus digitorum, Pro-
nator quadratus, Flexor carpi ulnaris,
Extensor carpi ulnaris. Anconeus,
Supinator brevis. Extensor ossis meta-
carpi pollicis, Extensor secundi inter-
nodii pollicis, and Extensor indicis.
Oleerantffz,
^oim SJu/ft at W^-yS^
The Radius.
The Radius is situated on the outer side of the fore-arm, lying parallel with the
ulna, which exceeds it in length and size. Its upper end is small, and forms only
a small part of the elbow-joint; but its lower end is large, and forms the chief part of
the wrist. It is one of the long bones, having a prismatic form, slightly curved
longitudinally, and presenting for examination a shaft and two extremities.
The Upper Extremity presents a head, neck, and tuberosity. The head is of
a cylindrical form, depressed on its upper surface into a shallow cup, which
receives the radial or lesser head of the humerus. Around the circumference
of the head is a smooth articular surface, coated with cartilage in the recent
state, broad internally where it articulates with the lesser sigmoid cavity of
the ulna, narrow in the rest of its circumference, to play in the orbicular liga-
ment. The head is supported on a round, smooth, and constricted portion of
bone, called the neck, which presents, behind, a slight ridge, for the attachment
RADIUS. 1 01
of part of the Supinator brevis. Beneath the neck, at the inner and front aspect
of the bone, is a rough eminence, the tuberosity. Its surface is divided into two
parts bj a vertical line — a posterior rough portion, for the insertion of the tendon
of the Biceps muscle; and an anterior smooth portion, on which a bursa is inter-
posed between the tendon and the bone.
The Shaft of the bone is prismoid in form, narrower above than below, and
slightly curved, so as to be convex outwards. It presents three surfaces, sepa-
rated by three borders.
The anterior border extends from the lower part of the tuberosity above, to the
anterior part of the base of the styloid process below. It separates the anterior
from the external surface. Its upper third is very prominent; and, from its
oblique direction downwards and outwards, has received the name of the oblique
line of the radius. It affords attachment, externally, to the Supinator brevis;
internally, to the Flexor longus pollicis, and between these to the Flexor digito-
rum sublimis. The middle third of the anterior border is indistinct and rounded.
Its lower fourth is sharp, prominent, affords attachment to the Pronator quadra-
tus, and terminates in a small tubercle, into which is inserted the tendon of the
Supinator longus.
The posterior border commences above, at the back part of the neck of the
radius, and terminates below, at the posterior part of the base of the styloid pro-
cess; it separates the posterior from the external surface. It is indistinct above
and below, but well marked in the middle third of the bone.
The internal or interosseous border commences above, at the back part of the
tuberosity, where it is rounded and indistinct, becomes sharp and prominent as it
descends, and at its lower part bifurcates into two ridges, which descend to the
anterior and posterior margins of the sigmoid cavity. This border separates the
anterior from the posterior surface, and has the interosseous membrane attached
to it throughout the greater part of its extent.
The anterior surface is narrow and concave for its upper two-thirds, and gives
attachment to the Flexor longus pollicis muscle; below, it is broad and flat, its
lower fourth giving attachment to the Pronator quadratus. At the junction of
the upper and middle thirds of this surface is the nutritious foramen, which is
directed obliquely upwards.
The posterior surface is rounded, convex, and smooth in the upper third of its
extent, and covered by the Supinator brevis muscle. Its middle third is broad,
slightly concave, and gives attachment to the Extensor ossis metacarpi pollicis
above, the Extensor primi internodii pollicis below. Its lower third is broad,
convex, and covered by the tendons of the muscles which subsequently run in the
grooves on the lower end of the bone.
The external surface is rounded and convex throughout its entire extent. Its
upper third gives attachment to the Supinator brevis muscle. About its centre
is seen a rough ridge, for the insertion of the Pronator radii teres muscle. Its
lower part is narrow, and covered by the tendons of the Extensor ossis metacarpi,
and Extensor primi internodii pollicis muscles.
The Lower Extremity of the radius is large, of quadrilateral form, and provided
with two articular surfaces, one at the extremity, and one at the inner side of the
bone; it presents, also, three borders, an anterior, posterior, and external. The
articular surface at the ©xtremity of the bone is of triangular form, concave,
smooth, and divided by a slight ridge into two parts. Of these, the external is
large, of a triangular form, and articulates with the scaphoid bone; the inner,
smaller and quadrilateral, articulates with the semi-lunar. The articular surface
at the inner side of the bone is called the sigmoid cavity of the radius ; it is
narrow, concave, smooth, and articulates with the head of the ulna.
Its anterior border, rough and irregular, affords attachment to the anterior
ligament of the wrist-joint. Its external border is prolonged obliquely down-
wards upon the margin of a strong conical projection, the styloid process, which
gives attachment by its base to the tendon of the Supinator longus, and by its
apex to the external lateral ligament of the wrist-joint. The outer surface of
102
OSTEOLOGY.
this process is marked by two grooves, which run obliquely downwards and for-
wards, and are separated from one another by an elevated ridge. The most ante-
rior one gives passage to the tendon of the Extensor ossis metacarpi pollicis, the
posterior one to the tendon of the Extensor primi internodii pollicis. Its posterior
border is convex, affords attachment to the posterior ligament of the wrist, and is
marked by three grooves. The most external is broad, but shallow, and sub-
divided into two by a slightly elevated ridge. The external groove transmits the
tendon of the Extensor carpi radialis longior, the inner one the tendon of the
Extensor carpi radialis brevior. Near the centre of the bone is a deep, but nar-
row, groove, directed obliquely from above downwards and outwards; it transmits
the tendon of the Extensor secundi
83. — Plan of the Development of the Eadius.
By Three Centres.
AjpjicaTS at 5pliy-
B>«-^
) —V'nJtes with Shaft 1
'/hott.-C
internodii pollicis. Internally is a
broad groove, for the passage of the
tendons of the Extensor communis
digitorum, and that of the Extensor
indicis ; the tendon of the Extensor
minimi digiti passing through the
groove at its point of articulation with
the ulna.
Development (fig. 83). By three
centres: one for the shaft, and one for
each extremity. That for the shaft,
makes its appearance near the centre
of the bone, soon after the develop-
ment of the humerus commences. At
birth, the shaft is ossified; but the
ends of the bone are cartilaginous.
About the end of the second year,
ossification commences in the lower
epiphysis; and about the fifth year, in
the upper one. At the age of puberty,
the upper epiphysis becomes joined to
the shaft; the lower epiphysis becom-
ing united about the twentieth year.
Articulations. With four bones ; the
humerus, ulna, scaphoid, and semi-
lunar.
Attachment of Muscles. To the tuberosity, the Biceps ; to the oblique ridge,
the Supinator brevis. Flexor digitorum sublimis, and Flexor longus pollicis; to
the shaft (its anterior surface), the Flexor longus pollicis and Pronator quadratus,
(its posterior surface) the Extensor ossis metacarpi pollicis, and Extensor primi
internodii pollicis; to the outer surface, the Pronator radii teres; and to the styloid
process, the Supinator longus.
k
Appears at Zv^-y.^ — ^1
^iir^tr.^it^J
THE HAND.
The Hand is subdivided into three segments, the Carpus or wrist, the Meta-
carpus or palm, and the Phalanges or fingers.
Carpus.
The bones of the Cai-pus, eight in number, are arranged in two horizontal rows.
Those of the upper row, enumerated from the radial to the ulnar side, are the
scaphoid, semi-lunar, cuneiform, and pisiform; those of the lower row, enumerated
m the same order, are the trapezium, trapezoid, magnum, and unciform.
Common Characters of the Carpal Bones.
Each bone (excepting the pisiform) presents six surfaces. Of these, the ante-
rior or palmar, and the posterior or dorsal, are rough, for ligamentous attach-
CARPUS.
103
ment, the dorsal surface being generally the broadest of the two. The superior
and iyiferior are articular, the superior generally convex, the inferior concave;
and the internal and external are also articular when in contact with contiguous
bones, otherwise rough and tubercular. Their structure in all is similar, con-
sisting within of a loose cancellous tissue enclosed in a thin layer of compact
tissue. Each bone is also developed from a single centre of ossification.
Bones of the Upper Row. (Figs, 84, 85.)
The Scaphoid is the largest bone of the first row. It has received its name
from its fancied resemblance to a boat, being broad at one end, and narrowed like
a prow at the opposite. It is situated at the superior and external part of the
carpus, its direction being from, above downwards, outwards, and forwards. Its
superior surface is convex, smooth, of triangular shape, and articulates with the
lower end of the radius. Its inferior surface, directed downwai'ds, outwards, and
backwards, is smooth, convex, also triangular, and divided by a slight ridge into
two parts, the external of which articulates with the trapezium, the inner with
the trapezoid. Its posterior or dorsal surface presents a narrow, rough groove,
which runs the entire breadth of the bone, and serves for the attachment of liga-
ments. The anterior or palmar surface is concave above, and elevated at its
lower and outer part into a prominent rounded tubercle, which projects forwards
from the front of the carpus, and gives attachment to the anterior annular liga-
ment of the wrist. The external surface is rough and narrow, and gives attach-
ment to the external lateral ligament of the wrist. The internal surface presents
two articular facets: of these, the superior or smaller one is flattened, of semi-
lunar form, and articulates with the semi-lunar; the inferior or larger is concave,
forming, with the semi-lunar bone, a concavity for the head of the os magnum.
To ascertain to which hand this bone belongs, hold the convex radial articular
surface upwards, and the dorsal surface backwards; the prominent tubercle will
be directed to the side to which the bone belongs.
Articulations. With five bones; the radius above, trapezium and trapezoid be-
low, OS magnum and semi-lunar internally.
The Semi-lunar bone may be distinguished by its deep concavity and crescentic
outline. It is situated in the centre of the upper range of the carpus, between
the scaphoid and cuneiform. Its superior surface, convex, smooth, and quadri-
lateral in form, articulates with the radius. Its inferior surface is deeply con-
cave, and of greater extent from before backwards, than transversely; it articu-
lates with the head of the os magnum, and by a long narrow facet (separated by
a ridge from the general surface) with the unciform bone. Its anterior or palmar
and posterior or dorsal surfaces are rough, for the attachment of ligaments, the
former being the broader, and of somewhat rounded form. The external surface
presents a narrow, flattened, semi-lunar facet, for articulation with the scaphoid.
The internal surface is marked by a smooth, quadrilateral facet, for articulation
with the cuneiform.
To ascertain to which hand this bone belongs, hold it with the dorsal surface
upwards, and the convex articular surface backwards; the quadrilateral articular
facet will then point to the side to which the bone belongs.
Articulations. With five bones : the radius above, os magnum and unciform
below, scaphoid and cuneiform on either side.
The Cuneiform {V Os Pyramidal), may be distinguished by its pyramidal shape,
and from having an oval-shaped, isolated facet, for articulation with the pisiform
bone. It is situated at the upper and inner side of the carpus. The superior
surface presents an internal, rough, non-articular portion ; and an external or
articular portion, which is convex, smooth, and separated from the lower end
of the ulna by the inter-articular fibro-cartilage of the wrist. The inferior
surface, directed outwards, is concave, sinuously curved, and smooth, for articu-
lation with the unciform. Its posterior or dorsal surface is rough, for the attach-
ment of ligaments. Its anterior or palmar surface presents, at its inner side, an
104
OSTEOLOGY.
oval-shaped facet, for articulation with the pisiform; and is rough externally, for
ligamentous attachment. Its external surface, the base of the pyramid, is marked
84. — Bones of the Left Hand. Dorsal Surface.
' -^^RPl
tvr.
'"""'' ^Aot^U
"^'■fRwooij
"VTeBMODli"
by a flat, quadrilateral, smooth facet, for articulation with the semi-lunar. The
internal surface, the summit of the pyramid, is pointed and roughened, for the
attachment of the internal lateral lia;ament of the wrist.
I
I
CARPUS.
105
To ascertain to which hand tliis bone belongs, liold it so that the base is
directed backwards, and the articular facet for the pisiform bone upwards; the
concave articular facet will point to the side to which the bone belongs.
Articulations. With three bones: the semi-lunar externally, the pisiform in
front, the unciform below, and with the triangular inter- articular fibro-cartilage
which separates it from the lower end of the ulna.
The Pisiform bone may be known by its small size, and from its presenting a
single articular facet. It is situated at the anterior and inner side of the carpus,
is nearly circular in form, and presents on its posterior surface a smooth, oval
facet, for articulation with the cuneiform bone. This facet approaches the supe-
rior, but not the inferior, border of the bone. Its anterior or palmar surface is
rounded and rough, and gives attachment to the anterior annular ligament. The
outer and inner surfaces are also rough, the former being convex, the other
usually concave.
To ascertain to which hand it belongs, hold the bone with its posterior or arti-
cular facet downwards, and the non-articular portion of the same surface back-
wards; the inner concave surface will then point to the side to which the bone
belongs.
Articulations. With one bone, the cuneiform.
Attachment of Muscles. To two : the Flexor carpi ulnaris, and Abductor
minimi digiti; and to the anterior annular ligament.
Bones of the Lower Row. (Figs. 84, 85.)
The Trapezium is of very irregular form. It may be distinguished by a deep
groove, for the tendon of the Flexor carpi radialis muscle. It is situated at the
external and inferior part of the carpus, between the scaphoid and first meta-
carpal bone. The superior surface, concave and smooth, is directed upwards and
inwards, and articulates with the scaphoid. Its inferior surface, directed down-
wards and outwards, is oval, concave from side to side, convex from before back-
wards, so as to form a saddle- shaped surface, for articulation with the base of the
first metacarpal bone. The anterior or palmar surface is narrow and rough.
At its upper part is a deep groove, running from above obliquely downwards and
inwards; it transmits the tendon of the Flexor carpi radialis, and is bounded
externally by a prominent ridge, the oblique ridge of the trapezium. This sur-
face gives attachment to the Abductor pollicis. Flexor ossis metacarpi, and Flexor
brevis pollicis muscles ; and the anterior annular ligament. The posterior or
dorsal surface is rough, and the external surface also broad and rough, for the
attachment of ligaments. The internal surface presents two articular facets; the
upper one, large and concave, articulates with the trapezoid ; the lower one,
narrow and flattened, with the base of the second metacarpal bone.
To ascertain to which hand it belongs, hold the bone with the grooved palmar
surface upwards, and the external, broad, non-articular surface backwards; the
saddle-shaped surface will then be directed to the side to which the bone
belongs.
Articulations. With four bones: the scaphoid above, the trapezoid and second
metacarpal bones internally, the first metacarpal below.
Attachment of Muscles. Abductor pollicis. Flexor ossis metacarpi, part of the
Flexor brevis pollicis, and the anterior annular ligament.
The Trapezoid is the smallest bone in the second row. It may be known by
its wedge-shaped form; its broad end occupying the dorsal, its narrow end the
palmar surface of the hand. Its superior surface, quadrilateral in form, smooth
and slightly concave, articulates with the scaphoid. The inferior surface articu-
lates with the upper end of the second metacarpal bone; it is convex from side to
side, concave from before backwards, and subdivided, by an elevated ridge, into
two unequal lateral facets. The posterior or dorsal, and anterior or palmar
surfaces are rough, for the attachment of ligaments; the former being the larger
of the two. The external surface, convex and smooth, articulates with the
io6
OSTEOLOGY.
trapezium. The internal surface is concave and smooth below, for articulation
with the OS magnum, rough above, for the attachment of an interosseous ligament.
To ascertain to which side this bone belongs, let the broad dorsal surface be
85. — Bones of the Left Hand. Palmar Surface.
FLEXOR^ CARPJ ULNARIS
FLEXOR BRE.VI5 MINIMI DICITI
FLEXOR OSSIS METACARPI
MINIMI DICITI
ME-"^'"'''''
Metaear/iUyS
rUEKi BREVIS
&
ABDUCTOR
MINIMI DICITI
Sesamoid
PBOFONOUS
held upwards, and its inferior concavo-convex surface forwards; the internal con-
cave surface will then point to the side to which the bone belongs.
Articulations. With four bones ; the scaphoid above, second metacarpal bone
below, trapezium externally, os magnum internally.
CAEPUS.
107
Attachment of Muscles. Part of the Flexor brevis pollicis.
The Os Magnum is the largest bone of the carpus, and occupies the centre of
the wrist. It presents, above, a rounded portion or head, which is received into
the concavity formed by the scaphoid and senai-lunar bones; a constricted portion
or neck; and, below, the body. Its superior surface is rounded, smooth, and
articulates with the semi-lunar. Its inferior surface is divided, by two ridges,
into three facets, for articulation with the second, third, and fourth metacarpal
bones; that for the third (the middle facet) being the largest of the three. The
posterior or dorsal surface is broad and rough, and the anterior or palmar nar-
row, rounded, but also rough, for the attachment of ligaments. The external
surface articulates with the trapezoid by a small facet at its anterior inferior
angle, behind which is a rough depression, for the attachment of an interosseous
ligament. Above this is a deep and rough groove, which forms part of the neck,
and serves for the attachment of ligaments, bounded superiorly by a smooth, con-
vex surface, for articulation with the scaphoid. The internal surface articulates
with the unciform by a smooth, concave, oblong facet, which occupies its posterior
and superior parts; rough in front, for the attachment of an interosseous liga-
ment.
To ascertain to which hand this bone belongs, the rounded head should be held
upwards, and the broad dorsal surface forwards ; the internal concave articular
surface will point to its appropriate side.
Articulatiotis. With seven bones : the scaphoid and semi-lunar above ; the
second, third, and fourth metacarpal below; the trapezoid on the radial side; and
the unciform on the ulnar side.
Attachment of Muscles. Part of the Flexor brevis pollicis.
The Unciform bone may be readily distinguished by its wedge-shaped form,
and the hook-like process that projects from its palmar surface. It is situated at
the inner and lower angle of the carpus, with its base downwards, resting on the
two inner metacarpal bones, and its apex directed upwards and outwards. Its
superior surface, the apex of the wedge, is narrow, convex, smooth, and articu-
lates with the semi-lunar. Its inferior surface articulates with the fourth and
fifth metacarpal bones, the concave surface for each being separated by a ridge,
which runs from before backwards. The posterior or dorsal surface is triangular
and rough, for ligamentous attachment. The anterior or palmar surface presents
at its lower and inner side a curved, hook-like process of bone, the unciform pro-
cess, directed from the palmar surface forwards and outwards. It gives attach-
ment, by its apex, to the annular ligament; by its inner surface, to the Flexor
brevis minimi digiti, and the Flexor ossis metacarpi minimi digiti; and is grooved
on its outer side, for the passage of the Flexor tendons into the palm of the hand.
This is one of the four eminences on the front of the carpus, to which the anterior
annular ligament is attached; the others being the pisiform internally, the oblique
ridge of the trapezium and the tuberosity of the scaphoid externally. The inter-
nal surface articulates with the cuneiform by an oblong surface, cut obliquely
from above downwards and inwards. Its external surface articulates with the
OS magnum by its upper and posterior part, the remaining portion being rough,
for the attachment of ligaments.
To ascertain to which hand it belongs, hold the apex of the bone upwards, and
the broad dorsal surface backwards ; the concavity of the unciform process will be
directed to the side to which the bone belongs.
Articulations. With five bones : the semi-lunar above, the fourth and fifth
metacarpal below, the cuneiform internally, the os magnum externally.
Attachment of Muscles. To two: the Flexor brevis minimi digiti, the Flexor
ossis metacarpi minimi digiti; and to the anterior annular ligament.
The Metacarpus..
The Metacarpal bones are five in number; they are long cylindrical bones,
presenting for examination a shaft and two extremities.
io8 OSTEOLOGY.
Common Characters of the Metacarpal Bones.
The shaft is prismoid in form, and curved longitudinally, so as to be convex in
the longitudinal direction behind, concave in front. It presents three surfaces;
two lateral, and one posterior. The lateral surfaces are concave, for the attach-
ment of the Interossei muscles, and separated from one another by a prominent
line. The posterior or dorsal surface is triangular, smooth, and flattened below,
and covered, in the recent state, by the tendons of the Extensor muscles. In its
upper half, it is divided by a ridge into two nai'row lateral depressions, for the
attachment of the Dorsal interossei muscles. This ridge bifurcates a little above
the centre of the bone, and its branches run to the small tubercles on each side of
the digital extremity.
The carpal extremity, or hase, is of a cuboidal form, and broader behind than
in front: it articulates, above, with the carpus; and on each side with the adjoin-
ing metacarpal bones ; its dorsal and palmar surfaces being rough, for the
attachment of tendons and ligaments.
The digital extremity, or head, presents an oblong surface, flattened at each
side, for artictxlation with the first phalanx; it is broader and extends farther
forwards in front than behind; and longer in the antero-posterior, than in the
transverse diameter. On either side of the head is a deep depression, surmounted
by a tubercle, for the attachment of the lateral ligament of the metacarpo-phalan-
geal joint. The posterior surface, broad and flat, supports the Extensor tendons;
and the anterior surface presents a median groove, bounded on each side by a
tubercle, for the passage of the Flexor tendons.
Peculiar Metacarpal Bones.
The metacarpal bone of the thumb is shorter and wider than the rest, diverges
to a greater degree from the carpus, and its palmar surface is directed inwards
towards the palm, The shaft is flattened and broad on its dorsal aspect, and does
not present the bifurcated ridge peculiar to the other metacarpal bones; concave
from before backwards on its palmar surface. The carpal extremity, or base,
presents a concavo-convex surface, for articulation with the trapezium, and has
no lateral facets. The digital extremity is less convex than that of the other
metacarpal bones, broader from side to side than from before backwards, and ter-
minates anteriorly in a small articular eminence on each side, over which play
two sesamoid bones.
The metacarpal bone of the index finger is the longest, and its base the largest
of the other four. Its carpal extremity is prolonged upwards and inwards; and
its dorsal and palmar surfaces are rough, for the attachment of tendons and liga-
ments. It presents four articular facets: one at the end of the bone, which has
an angular depression for articulation with the trapezoid; on the radial side, a
flat quadrilateral facet, for articulation with the trapezium; its ulnar side being
prolonged upwards and inwards, to articulate above with the os magnum, inter-
nally with the third metacarpal bone.
The metacarpal bone of the middle finger is a little less in size than the pre-
ceding; it presents a pyramidal eminence on the radial side of its base (dorsal
aspect), which extends upwards behind the os magnum. The carpal-articular
facet is concave behind, flat and horizontal in front, and corresponds to the os
magnum. On the radial side is a smooth, concave facet, for articulation with the
second metacarpal bone; and on the ulnar side two small oval facets, for articula-
tion with the third metacarpal.
The metacarpal bone of the ring-finger is shorter and smaller than the pre-
ceding, and its base small and quadrilateral; its carpal surface presenting two
facets, for articulation with the unciform and os magnum. On the radial side are
two oval facets, for articulation with the third metacarpal bone;- and on the ulnar
side a single concave facet, for the fifth metacai'pal.
METACARPUS AND PHALANGES.
109
The metacarpal bone of the little finger may be distinguished by the concavo-
convex form of its carpal surface, for articulation with the unciform, and from
having only one lateral articular facet, which corresponds with the fourth meta-
carpal bone. On its ulnar side, is a prominent tubercle for the insertion of the
tendon of the Extensor carpi ulnaris. The dorsal surface of the shaft is marked
by an oblique ridge, which extends from near the inner side of the upper extremity,
to the outer side of the lower. The outer division of this surface serves for the
attachment of the fourth Dorsal interosseous muscle; the inner division is smooth,
and covered by the Extensor tendons of the little finger.
Articulations. The first, with the trapezium; the second, with the trapezium,
trapezoides, os magnum, and third metacarpal bones; the third, with the os mag-
num, and second and fourth metacarpal bones; the fourth, with the os magnum,
unciform, and third and fifth metacarpal bones; and the fifth, with the unciform
and fourth metacarpal.
Attachment of Muscles. To the metacarpal bone of the thumb, three: the Flexor
ossis metacarpi pollicis. Extensor ossis metacarpi pollicis, and first Dorsal inter-
osseous. To the second metacarpal bone, five: the Flexor carpi radialis. Extensor
carpi radialis longior, first and second Dorsal interosseous, and first Palmar inter-
osseous. To the third, five: the Extensor carpi radialis brevior. Flexor brevis
pollicis. Adductor pollicis, and second and third Dorsal interosseous. To the
fourth, three: the third and fourth Dorsal interosseous and second Palmar. To
the fifth, four: the Extensor carpi ulnaris. Flexor carpi ulnaris, Flexor ossis meta-
carpi minimi digiti, and third Dorsal interosseous.
Phalanges.
The Phalanges are the bones of the fingers; they are fourteen in number, three
for each finger and two for the thumb. They are long bones, and present for
examination a shaft, and two extremities. The shaft tapers from above down-
wards, is convex posteriorly, concave in front from above downwards, flat from
side to side, and marked laterally by rough ridges, which give attachment to the
fibrous sheaths of the Flexor tendons. The metacarpal extremity or base, in the
first row, presents an oval concave articular surface, broader from side to side,
than from before backwards; and the same extremity in the other two rows, a
double concavity separated by a longitudinal median ridge, extending from before
backwards. The digital extremities are smaller than the others, and terminate,
in the first and second row, in two small lateral condyles, separated by a slight
groove, the articular surface being prolonged farther forwards on the palmar, than
on the dorsal surface, especially in the first row.
The Ungual phalanges are convex on their dorsal, flat on their palmar surfaces,
they are recognised by their small size, and from their ungual extremity presenting,
on its palmar aspect, a roughened elevated surface of a horse-shoe form, which
serves to support the sensitive pulp of the finger.
Articulations. The first row with the metacarpal bones, and the second row of
phalanges; the second row, with the first and third; the third, with the second
row.
Attachment of Muscles. To the base of the first phalanx of the thumb, four
muscles: the Extensor primi internodii pollicis. Flexor brevis pollicis, Abductor
pollicis. Adductor pollicis. To the second phalanx, two: the Flexor longus pollicis,
and the Extensor secundi internodii. To the base of the first phalanx of the
index finger, the first Dorsal and the first Palmar interosseus; to that of the middle
finger, the second and third Dorsal interosseous; to the ring finger, the fourth
Dorsal and the second Palmar interosseous; and to that of the little finger, the
third Palmar interosseous, the Flexor brevis minimi digiti, and Abductor minimi
digiti. To the second phalanges, the Flexor sublimis digitorum. Extensor com-
munis digitorum; and, in addition, the Extensor indicis, to the index finger; the
Extensor minimi digiti, to the little finger. To the third phalanges, the Flexor
profundus digitorum and Extensor communis digitorum.
no
OSTEOLOGY.
Development op the Hand.
The Carpal bones are each developed by a single centre; at birth they are all
cartilagmous. Ossification proceeds in the following order (fig. 86); in the os
magnum and unciform an ossific point appears during the first year, the former
preceding the latter; in the cuneiform, at the third year; in the trapezium and semi-
lunar, at the fifth year, the former preceding the latter; in the scaphoid, at the
sixth year; in the trapezoid, during the eighth year; and in the pisiform, about
the twelfth year.
86. — Plan of the Development of the Hand.
Carpus
1. cenfrejbr each lone
All cartiJcfqinous at Zirtli '^J^. ,
Metacarpus
2 Centres for each tone
IforShocft-
i -for DiqituJ Extremity
except /-^
5^>
The Metacarpal hones are developed each by two centres: one for the shaft, and
one for the digital extremity, for the four inner metacarpal bones; one for the
shaft and one for the base, for the metacarpal bone of the thumb, which, in this
respect, resembles the phalanges. Ossification commences in the centre of the
shaft about the sixth week, and gradually proceeds to either end of the bone;
about the third year the digital extremity of the four inner metacarpal bones and
the base of the first metacarpal, commence to ossify, and they unite about the
twentieth year.
The Phalanges are each developed by two centres: one for the shaft and one
for the base. Ossification commences in the shaft, in all three rows, at about the
sixth week, and gradually involves the whole of the bone excepting the upper
extremity. Ossification of the base commences in the first row between the third
and fourth years, and a year later in those of the second and third row. The two
centres become united between the eighteenth and twentieth years.
FEMUE.
Ill
THE LOWER EXTREMITY.
87, — Riglit Femur. Anterior Surface.
V^
The Lower Extremities, two in num- obtur«tor intehnus
ber, are connected witli the inferior part pvrtor.,,!
of the trunk. They are divided into three
parts, the thigh, the leg, and the foot,
which correspond to the arm, the forearm,
and hand in the upper extremity.
The thigh is formed of a single bone,
the femur.
LICAMENTUM TCRE!
ml
The Femur.
The Femur is the longest, largest, and
heaviest bone in the skeleton, and almost
perfectly cylindrical in the greater part
of its extent. In the erect position of the
body it is not vertical, but presents a
general curvature in the longitudinal
direction, which renders the bone convex
in front and slightly concave behind; it
also gradually inclines from above down-
wards and inwards, approaching its fellow
towards its lower part, but separated
from it above by a very considerable in-
terval which corresponds to the entire
breadth of the pelvis. The degree of
this inclination varies in different persons,
and is greater in the female than in the
male. The femur, like other long bones,
is divisible into a shaft and two extremi-
ties.
The Upper Extremity presents for ex-
amination a head, neck, and the greater
and lesser trochanters.
The head, which is globular, and forms
rather more than a hemisphere, is directed
upwards, inwards, and a little forwards,
the greater part of its convexity being
above and in front. Its surface is smooth,
coated with cartilage in the recent state,
and presents a little behind and below
its centre a rough depression, for the
attachment of the ligamentum teres.
The neck is a flattened pyramidal pro-
cess of bone, which connects the head
with the shaft. It varies in length and
obliquity at various periods of life, and
under different circumstances. In the
adult male, it forms an obtuse angle with
the shaft, being directed upwards, in-
wards, and a little forwards. In the
female, it approaches more nearly a right
angle. Occasionally, in very old subjects,
and more especially in those greatly de-
bilitated, its direction becomes horizontal,
so that the head sinks below the level
of the trochanter, and its length diminishes
h;^»*
\ :
SUB'CRUREOS
.l^i
w
'^erCoiM'
"n^vlf
112 OSTEOLOGY.
to such a degree, that the head becomes almost contiguous with the shaft. The
neck, is flattened from before backwards, contracted in tlie middle, and broader at
its outer extremity, where it is connected with the shaft, than at its summit, where
it is attached to the head. It is much broader in the vertical than in the ante-
rior posterior diameter, on account of the greater amount of resistance required in
sustaining the weight of the trunk. Its anterior surface, narrower than the
posterior, is perforated by numerous vascular foramina. Its posterior surface is
smooth, broader, and more concave than the anterior, and receives towards its
outer side the attachment of the capsular ligament of the hip. Its superior border
is short and thick, bounded externally by the great trochanter, and its surface
perforated by large foramina. Its inferior border, long and narrow, curves a
little backwards, to terminate at the lesser trochanter.
The Greater Trochanter is a large irregular quadrilateral eminence, situated at
the outer side of the neck, at its junction with the upper part of the shaft. It is
directed a little outwards and backwards, and rises less high than the head. It
presents for examination two surfaces and four borders.
Its external surface, quadrilateral in form, is broad, rough, convex, and marked
by a prominent diagonal line, which extends from the posterior superior to the
anterior inferior angle: this line serves for the attachment of the tendon of the
Gluteus medius. Above the line is a triangular surface, sometimes rough for
part of the tendon of the same muscle, sometimes smooth for the interposition of a
bursa between that tendon and the bone. Below and behind the diagonal line is
a smooth triangular surface, over which the tendon of the Gluteus maximus muscle
plays, a bursa being interposed. The internal surface is of much less extent than
the external, and presents at its base a deep depression, the digital or trochan-
teric fossa, for the attachment of the tendon of the Obturator externus muscle.
The superior border is free; it is thick and irregular, and marked by im-
pressions for the attachment of the Pyriformis behind, the Obturator internus and
Gemelli in front. >The inferior border is placed at the point of junction of the
trochanter with the outer surface of the shaft; it is rough, prominent, slightly
curved, and gives attachment to the upper part of the Vastus externus muscle.
The anterior border is prominent, somewhat irregular, as well as the surface of
bone immediately below it; it afiords attachment by its outer part to the Gluteus
minimus. The posterior border is very prominent, and appears as a free rounded
edge, which forms the back part of the digital fossa.
The Lesser Trochanter is a conical eminence, which varies in size in different
subjects; it is situated at the lower and back part of the base of the neck. Its
base is triangular, and connected with the adjacent parts of the bone by three
well-marked borders: of these the superior is continuous with the lower border of
the neck; \hQ posterior, with the posterior intertrochanteric line; and the inferior
with the middle bifurcation of the linea aspera. Its summit, which is directed
inwards and backwards, is rough, and gives insertion to the tendon of the Psoas
magnus. The Iliacus is inserted into the shaft below the lesser trochanter, be-
tween the Vastus internus in front, and the Pectineus behind. A well marked
prominence, but of variable size, situated at the upper and front part of the
neck, at its junction with the great trochanter, is called the tubercle of the
femur; it is the point of meeting of three- muscles, the Gluteus minimus exter-
nally, the Vastus externus below, and the tendon of the Obturator internus and
Gemelli above. Running obliquely downwards and inwards from the tubercle is
the spiral line of the femur, or anterior intertrochanteric line; it winds around the
inner side of the shaft, below the lesser trochanter, and terminates in the linea .
aspera, about two inches below this eminence. Its upper half is rough, and affords
attachment to the capsular ligament of the hip joint; its lower half is less promi-
nent and gives attachment to the upper part of the Vastus internus. The posterior
inter-trochanteric line is very prominent, and runs from the summit of the great
trochanter downwards and inwards to the upper and back part of the lesser tro-
chanter. Its upper half forms the posterior border of the great trochanter. A
FEMUR.
well-marked eminence commences about
the centre of the posterior inter-troclian-
teric line, and passes vertically down-
wards for about two inches along the
back part of the shaft: it is called the
linea quadrati, and gives attachment to
the Quadratus femoris, and a few fibres
of the Adductor magnus muscles.
The Shaft, almost perfectly cylindrical
in form, is a little broader above than in
the centre, and somewhat flattened from
before backwards below. It is curved from
before backwards, smooth and convex in
front, and strengthened behind by a pro-
minent longitudinal ridge, the linea
aspera. It presents for examination three
borders separating three surfaces. Of
the three borders, one, the linea aspera,
is posterior, the other two are placed
laterally.
The linea a5joera(fig.88) is a prominent
longitudinal ridge or crest, presenting on
the middle third of the bone an external
lip, an internal lip, and a rough inter-
mediate space. A little above the centre
of the shaft, this crest divides into three
lines; the most external one becomes
very rough, and is continued almost ver-
tically upwards to the base of the great
trochanter; the middle one, the least dis-
tinct, is continued to the base of the
trochanter minor; and the internal one
is lost above in the spiral line of the
femur. Below, the linea aspera divides
into two bifurcations, which enclose be-
tween them a triangular space (the po-
pliteal space), upon which rests the
popliteal artery. Of these two bifurca-
cations, the outer branch is the most
prominent, and descends to the summit
of the outer condyle. The inner branch
is less marked, presents a broad and
shallow groove for the passage of the
femoral artery, and terminates at a small
tubercle at the summit of the internal
condyle.
To the inner lip of the linea aspera,
its whole length, is attached the Vastus
internus; and to the whole length of the
outer lip the Vastus externus. The
Adductor magnus is also attached to the ^/o";
whole length of the linea aspera, being ^"]y^
connected with the outer lip above, and '""""
the inner lip belov/. Between the Vastus
externus and the Adductor magnus are
attached two muscles, viz., the Gluteus
maximus above, and the short head of the
I
-Right Femur. Posterior Surface.
V
,v^-
' rohlUeallSJiac
vtir'ffc^
- t^oovB' j'oT tcttMon
of
PaPI_ITEU5
°^«^
\¥'fk
■^^
'Art^'
114 OSTEOLOGY.
Biceps below. Between the Adductor magnus and the Vastus internus four
muscles are attached: the Iliacus and Pectineus above (the latter to the middle
division of the upper bifurcation) ; below these, the Adductor brevis and Adductor
longus. The linea aspera is perforated a little below its centre by the nutritious
canal, which is directed obliquely from below upwards.
The two lateral borders of the femur are only very slightly marked, the
external extending from the anterior inferior angle of the great trochanter to the
anterior extremity of the external condyle; the internal passes from the spiral
line, at a point opposite the trochanter minor, to the anterior extremity of the
internal condyle. The internal border marks the limit of attachment of the Cru-
rseus muscle internally.
The anterior surface includes that portion of the shaft which is situated be-
tween the two lateral borders. It is smooth, convex, broader above and below
than in the centre, slightly twisted, so that its upper part is directed forwards and
a little outwards, its lower part forwards and a little inwards. The upper three-
fourths of this surface serve for the attachment of the Crurseus; the lower fourth
is separated from this muscle by the intervention of the synovial membrane of the
knee-joint, and affords attachment to the Sub-crurasus to a small extent. The
external surface includes the portion of bone between the external border and the
outer lip of the linea aspera; it is continuous above with the outer surface of the
great trochanter, below with the outer surface of the external condyle: to its
upper three-fourths is attached the outer portion of the Crurseus muscle. The
internal surface includes the portion of bone between the internal border and the
inner lip of the linea aspera; it is continuous above with the lower border of
the neck, below with the inner side of the internal condyle: it is covered by the
Vastus internus muscle.
The Lower Extremity, larger than the upper, is of a cuboid form, flattened
from before backwards, and divided by an interval presenting a smooth depression
in front, and a notch of considerable size behind, into two large eminences, the
condyles. The interval is called the inter- condyloid notch. The external con-
dyle is the most prominent anteriorly, and is the broadest both in the antero-
posterior and transverse diameters. The internal condyle is the narrowest,
longest, and most prominent internally. This difference in the length of the two
condyles depends upon the obliquity of the thigh-bones, in consequence of their
separation above at the articulation with the pelvis. If the femur is held in this
oblique position, the surfaces of the two condyles will be seen to be nearly hori-
zontal. The two condyles are joined together anteriorly, and form a smooth
trochlear surface, the external border of which is more prominent, and ascends
higher than the internal one. This surface articulates with the patella. It pre-
sents a median groove, which extends downwards and backwards to the inter-
condyloid notch ; and two lateral convexities, of which the external is the broader,
more prominent, and prolonged farther upwards upon the front of the outer
condyle. The inter-condyloid notch lodges the crucial ligaments; it is bounded
laterally by the opposed surfaces of the two condyles, and in front by the lower
end of the shaft.
Outer Condyle. The outer surface of the external condyle presents, a little
behind its centre, an eminence, the outer tuberosity; it is less convex and pro-
minent than the inner tuberosity, and gives attachment to the external lateral
ligament of the knee. Immediately beneath it is a groove, which commences at
a depression a little behind the centre of the lower border of this surface: the
depression is for the tendon of origin of the Popliteus muscle; the groove in
which this tendon is contained is smooth, covered with cartilage in the recent
state, and runs upwards and backwards to the posterior extremity of the condyle.
The inner surface of the outer condyle forms one of the lateral boundaries of the
inter-condyloid notch, and gives attachment, by its posterior part, to the anterior
crucial ligament. The inferior surface is convex, smooth, and broader than that
of the internal condyle. The posterior extremity is convex and smooth : just
FEMUR.
"5
89. — Plan of the Development of the Femur,
by Five Centres.
Appears at i^yT -Vv*^!
J^f3iaftttioi(t18'}yV^
to'
Si
Ajijtears ateiTdofl.yV
Juins Shaft adout lS'}y '■
Appears 13 -14-* y^
^ Joins Simp about 18^ tjT
above the articular surface is a depression, for the tendon of the outer head of the
Gastrocnemius,
Inner Condyle. The inner surface of the inner condyle presents a convex
eminence, the inner tuberosity, rough, for the attachment of the internal lateral
ligament. Above this tuberosity, at the termination of the inner bifurcation of the
linea aspera, is a tubercle, for the insertion of the tendon of the Adductor magnus ;
and behind and beneath the tubercle a depression, for the tendon of the inner head
of the Gastrocnemius. The outer side of the inner condyle forms one of the lateral
boundaries of the inter- condyloid notch, and gives attachment, by its anterior
part, to the posterior crucial ligament. Its inferior or articular surface is con-
vex, and presents a less extensive surface than the external condyle.
Structure. Like that of the other cylindrical bones, the linear-aspera is com-
posed of a very dense, ivory-like, compact tissue.
Articulations. With three bones; the os innominatum, tibia, and patella.
Development (fig. 89). The femur
is developed by five centres ; one
for the shaft, one for each extre-
mity, and one for each trochanter.
Of all the long bones, it is the first to
show traces of ossification: this fi rst
commences in the shaft, at about the
fifth week of foetal life, the centre s of
ossification in the epiphyses appe ar-
ing in the following order. First , in
the lower end of the bone, at the
ninth month of foetal life ; from
this the condyles and tuberosities
are formed; in the head, at the end
of the first year after birth; in the
great trochanter, during the fourth
year; and in the lesser trochanter,
between the thirteenth and four-
teenth. The order in which the
epiphyses are joined to the shaft, is
the direct reverse of their appear-
ance; their junction does not com-
mence until after puberty, the lesser
trochanter being first joined, then
the greater, then the head, and,
lastly, the inferior extremity (the
first in which ossification com-
menced), which is not united until
the twentieth year.
Attachment of Muscles. To the great trochanter, the Gluteus medius. Gluteus
minimus, Pyriformis, Obturator internus. Obturator externus. Gemellus superior.
Gemellus inferior, and Quadratus femoris. To the lesser trochanter, the Psoas
magnus, and the Iliacus below it. To the shaft, its posterior surface, the Vastus
externus. Gluteus maximus, short head of the Biceps, Vastus internus, Adductor
magnus, Pectineus, Adductor brevis, and Adductor longus ; to its anterior surface,
the Crurseus and Sub-crui'£eus. To the condyles, the Gastrocnemius, Plantaris,
and Popliteus.
,'k
ovear'j- at
I'-fce-tal) ^^ ,,,.
Joins Shaft ae-ZO''-if:
THE LEG.
The Leg consists of three bones: the Patella, a large sesamoid bone, placed in
front of the knee, analogous to the olecranon process of the ulna; and the Tibia
and Fibula.
I 2
ii6
OSTEOLOGY.
Surface.
91- — Posteriot Surface.
The Patella. (Figs. 90, 91).
The Patella is a small, flat, triangular bone, situated at the anterior part of the
knee-joint. It resembles the sesamoid bones, from being developed in the tendon
of the Quadriceps extensor; but, in relation with the tibia, it may be regarded as
analogous to the olecranon process of the ulna, which occasionally exists as a sepa-
rate piece, connected to the shaft of that bone by a continuation of the tendon of
the Triceps muscle. It presents an anterior and posterior surface, three borders,
a base, and an apex.
The anterior surface is convex, perforated by small apertures, for the passage
of nutrient vessels, and marked by numerous rough,
90.— Eight Patella, Anterior longitudinal striee. This surface is covered, in the
recent state, by an expansion from the tendon of the
Quadriceps extensor, separated from the integument by
a synovial bursa, and gives attachment below to the
ligamentum patellae. The posterior surface presents a
smooth, oval-shaped, articular surface, covered with car-
tilage in the recent state, and divided into two facets by
a vertical ridge, which descends from the superior to-
wards the inferior angle of the bone. The ridge cor-
responds to the groove on the trochlear surface of the
femur, and the two facets to the articular surfaces of
the two condyles; the outer facet, for articulation with
the outer condyle, being the broader and deeper, serves
to indicate the leg to which the bone belongs. This
surface presents, infer iorly, a roup,h, convex, non-arti-
cular depression, the lower half of which gives attach-
ment to the ligamentum patellae; the upper half being
separated from the head of the tibia by adipose tissue.
Its superior and lateral borders give attachment to
the tendon of the Quadriceps extensor; to the superior
border, that portion of the tendon which is derived from
the Rectus and Crurjeus muscles; and to the lateral
borders, the portion derived from the external and in-
ternal Yasti muscles.
The base, or superior border, is thick, directed upwards, and cut obliquely at
the expense of its outer surface; it receives the attachment, as already mentioned,
of part of the Quadriceps extensor tendon.
The apex is pointed, and gives attachment to the ligamentum patellae.
Structure. It consists of loose cancellous tissue, covered by a thin compact
lamina.
Development. By a single centre, which makes its appearance, according to
Beclard, about the third year. In two instances, I have seen this bone cartilagi-
nous throughout, at a much later period (six years). More rarely, the bone is
developed by two centres, placed side by side.
Articulations. With the two condyles of the femur.
Attachment of Muscles. Four muscles are attached to the patella, viz., the
Rectus, Cruraius, Vastus internus, and Vastus externus. The tendons of these
muscles joined at their insertion, constitute the Quadriceps extensor cruris.
The Tibia.
The Tibia (figs. 92, 93) is situated at the anterior and inner side of the leg, and,
excepting the femur, is the longest and largest bone in the skeleton. It is pris-
moid in form, expanded above, where it enters into formation with the knee joint,
and more slightly below. In the male, its direction is vertical, and parallel with
TIBIA.
117
the bono of the opposite side,
hut in the female it has a slight
oblique direction downwards and
outwards, to compensate for the
oblique direction of the femur
inwards. It presents for exami-
nation a shaft and two extre-
mities.
The Superior Extremity, or
head, is large and expanded on
each side into two lateral emi-
nences, the tuberosities. Supe-
riorly, the tuberosities present
two smooth concave surfaces,
which articulate with the con-
dyles of the femur; the internal
articular surface is longer than
the external, oval from before
backwards, to articulate with the
internal condyle; the external
one being broader, flatter, and
more circular, to articulate with
the external condyle. Between
the two articular surfaces, and
nearer the posterior than the
anterior aspect of the bone, is an
eminence, the spinous process of
the tibia, surmounted by a pro-
minent tubercle on each side,
which give attachment to the
extremities of the semilunar
fibro-cartilages; and in front and
behind the spinous process, a
rough depression for the attach-
ment of the anterior and poste-
rior crucial ligaments and the
semilunar cartilages. Anteriorly
the tuberosities are continuous
with one another, presenting a
large and somewhat flattened
triangular surface, broad above,
and perforated by large vascular
foramina, narrow beloAV, where
it terminates in a prominent
oblong elevation of large size,
the tubercle of the tibia; the
lower half of this tubercle is
rough, for the attachment of the
ligamentum patellae; the upper
half is a smooth facet corres-
ponding, in the recent state, with
a bursa which separates this
ligament from the bone. Poste-
riorly, the tuberosities are sepa-
rated from each other above by
a shallow depression, the popli-
teal notch, which gives attach-
92. — Bones of the Eight Leg, Anterior Surface.
JI e a el
StyJeiiJ VTi
iEactexnrtl Nalleotus
ii8 OSTEOLOGY.
ment to the posterior crucial ligament. The posterior surface of the inner
tuberosity presents a deep transverse groove, for the insertion of the tendon of
the Semi-membranosus; and the posterior surface of the outer one, a flat articular
facet, nearly circular in form, directed downwards, backwards, and outwards, for
articulation with the fibula. The lateral surfaces are convex and rough, the internal
one, the most prominent, gives attachment below to the internal lateral ligament.
The Shaft of the tibia is of a triangular prismoid form, broad above, gradually
decreasing in size to the commencement of its lower fourth, its most slender part,
and then enlarges again towards its lower extremity. It presents for examination
three surfaces and three borders.
The anterior border, the most prominent of the three, is called the crest of the
tibia, or in popular language, the shin; it commeiKies above at the tubercle, and
terminates below at the anterior margin of the inner malleolus. This border is
very prominent in the upper two-thirds of its extent, smooth and rounded below.
It presents a very flexuous course, being curved outwards above, and inwards
below; it gives attachment to the deep fascia of the leg.
The internal border is smooth and rouiided above and below, but more promi-
nent in the centre ; it commences at the back part of the inner tuberosity, and
terminates at the posterior border of the internal malleolus; its upper third gives
attachment to the internal lateral ligament of the knee, and to some fibres of the
Popliteus muscle; its middle third, to some fibres of the Soleus and Flexor longus
digitorum muscles.
The external border is thin and prominent, especially its central part, and gives
attachment to the interosseous membrane; it commences above in front of the
fibular articular facet, and bifurcates below, forming the boundaries of a triangular
rough surface, for the attachment of the inferior interosseous ligament, connecting
the tibia and fibula.
The internal surface is smooth, convex, and broader above than below;
its upper third, directed forwards and inwards, is covered by the aponeurosis
derived from the tendon of the Sartorius, and by the tendons of the Gracilis
and Semi-tendinosus, all of which are inserted nearly as far forwards, as the ante-
rior border; in the rest of its extent it is sub-cutaneous.
The external surface is narrower than the internal, its upper two-thirds present
a shallow groove for the attachment of the Tibialis anticus muscle; its lower third is
smooth, convex, curves gradually forwards to the anterior part of the bone, and is
covered from within outwards by the tendons of the following muscles: Tibialis
anticus. Extensor proprius poUicis, Extensor longus digitorum, Peroneus tertius.
The posterior surface (fig. 93) presents at its upper part a prominent ridge, the
oblique line of the tibia, which extends from the back part of the articular facet for
the fibula, obliquely downwards, to the internal border, at the junction of its
upper and middle thirds. It marks the limit for the insertion of the Popliteus
muscle, and serves for the attachment of the popliteal fascia, and part of the
Soleus, Flexor longus digitorum, and Tibialis posticus muscles; the triangular
concave surface, above, and to the inner side of this line, gives attachment to
the Popliteus muscle. The middle third of the posterior surface is divided by a
vertical ridge into two lateral halves; the ridge is well marked at its commence-
ment at the oblique line, but becomes gradually indistinct below; the inner and
broadest half gives attachment to the Flexor longus digitorum, the outer and
narrowest, to part of the Tibialis posticus. The remaining part of the bone is
covered by the Tibialis posticus, Flexor longus digitorum, and Flexor longus
pollicis muscles. Immediately below the oblique line is the medullary foramen,
which is directed obliquely downwards.
The Lower Extremity, much smaller than the upper, is somewhat quadrilateral
in form, and prolonged downwards, on its inner side, into a strong process, the
internal malleolus. The inferior surface of the bone presents a quadrilateral
smooth surface, for articulation with the astragalus; narrow internally, where
it becomes continuous with the articular surface of the inner malleolus, broader
TIBIA.
119
externally, and traversed from
before backwards by a slight
elevation, separating two lateral
depressions. The anterior sur-
face is smooth and rounded
above, and covered by the ten-
dons of the Extensor muscles of
the toes; its lower margin presents
a rough transverse depression, for
the attachment of the anterior
ligament of the ankle joint. The
posterior surface presents a
superficial groove directed
obliquely downwards and in-
wards, continuous with a simi-
lar groove on the posterior ex-
tremity of the astragalus, it
serves for the passage of the
tendon of the Flexor longus
poUicis. The external surface
presents a triangular rough de-
pression, the lower part of which,
in some bones, is smooth, covered
with cartilage in the recent state
and articulates with the fibula,
the remaining part is rough for
the attachment of the inferior
interosseous ligament, which
connects it with the fibula.
This surface is bounded by two
prominent ridges, continuous
above with the interosseous
ridge; they afford attachment
to the anterior and posterior
tibio-fibular ligaments. The
internal surface is prolonged
downwards to form a strong
pyramidal- shaped process, flat-
tened from without inwards, the
inner malleolus ; its inner surface
is convex and subcutaneous. Its
outer surface, smooth and slight-
ly concave, deepens the articular
surface for the astragalus. Its
anterior border is rough, for the
attachment of ligamentous fibres.
Its posterior border presents a
broad and deep groove, directed
obliquely downwards and in-
wards; it is occasionally double,
and transmits the tendons of the
Tibialis posticus and Flexor
longus digitorum muscles. Its
summit is marked by a rough
depression behind, for the attach-
ment of the internal lateral liga-
ment of the ankle joint.
93. — Bones of the Right Leg. Posterior Surface.
'otHt Teiriiu^
■yiozc
120
OSTEOLOGY.
^:^er eoctremit^
ApjpeccTS out birth-
^oin.!/ Shaft abowt
Structure. Like that of the other long bones.
Development. By three centres (fig. 94): one for the shaft, and one for each
extremity. Ossification commences in the centre of the shaft about the same time
^, „,i TN 1 , P ji m-i • as in the femur, the fiftli week, and
04. — Plan of the Development 01 the iibia. in j^ i . 3 •l^
By Three Centres. gradually extends towards either ex-
tremity. The centre for the upper
epiphysis appears at birth; it is flat-
tened in form, and has a thin tongue-
Bhaj)ed process in front, which forms
the tubercle. That for the lower
epiphysis appears in the second year.
The lover epiphysis joins the shaft
at about the twentieth year, and the
upper one about the twenty-fifth
year. Two additional centres occa-
sionally exist, one for the tongue-
shaped process of the upper epiphysis,
the tubercle, and one for the inner
malleolus.
Articulations. With three bones:
the femur, fibula, and astragalus.
Attachment of Muscles. To the
inner tuberosity, the Semi-membra-
nosus. To the outer tuberosity, the
Tibialis anticus and Extensor longus
digitorum: to the shaft; its internal
surface, the Sartorius, Gracilis, and
Semi-tendinosus: to its external sur-
face, the Tibialis anticus: to its poste-
A2>2>£(irs at 2.7.'^ j^
Jains Shaft a hou/f
20^ ?/.?
^'/i'e.r extre'^>^^^'^J
rior surface, the Popliteus, Soleus, Flexor longus digitorum, and Tibialis posticus:
to the tubercle, the ligamentum patellae.
The Fibula.
The Fibula (fig. 92, 93) is situated at the outer side of the leg. It is the
smaller of the two bones, and, in proportion to its length, the most slender of all
the long bones; it is placed nearly parallel with the. tibia, its lower extremity
inclining a little forwards, so as to be on a plane anterior to that of the upper end.
It presents for examination a shaft and two extremities.
The Superior Extremity or Head, is of an irregular rounded form, presenting
above a flattened articular facet, directed upwards and inwards, for articulation
with a corresponding facet on the external tuberosity of the tibia. On the outer
side is a thick and rough prominence, continued behind into a pointed eminence,
the styloid process, which projects upwards from the posterior part of the head.
The prominence above mentioned gives attachment to the tendon of the Biceps
muscle, and to the long external lateral ligament of the knee, the ligament dividing
this tendon into two parts. The summit of the styloid process gives attachment
to the short external lateral ligament. The remaining part of the circumference
of the head is rough, for the attachment, in front, of the anterior superior tibio-
fibular ligament, and the upper and anterior part of the Peroneus longus; and
behind, to the posterior superior tibio-fibular ligament, and the upper fibres of the
outer head of the Soleus muscle.
The Lower Extremity, called the malleolus externus, is of a pyramidal form, some-
Avhat flattened from without inwards, and is longer, and descends lower than the
internal malleolus. Its external surface is convex, sub-cutaneous, and continuous
with a triangular (also sub-cutaneous) surface on the outer side of the shaft. The
internal surface presents in front a smooth triangular facet, broader above than
below, convex from above downwards, which articulates with a corresponding
FIBULA. 121
surface on the outer side of the astragalus. Behind and beneath the articular
surface is a rough depression, which gives attachment to the posterior fasciculus of
the external lateral ligament of the ankle. Its anterior border is thick and rough,
and marked below by a depression for the attachment of the anterior fasciculus of
the external lateral ligament. The posterior border is broad and marked by a
shallow groove, for the passage of the tendons of the Peroneus longus and brevis
muscles. Its summit is rounded, and gives attachment to the middle fasciculus of
the external lateral ligament.
The Shaft presents three surfaces, and three borders. The anterior border com-
mences above in front of the head, runs vertically downwards to a little below the
middle of the bone, and then curving a little outwards, bifurcates below into two
lines, which bound the triangular sub-cutaneous surface immediately above the outer
side of the malleolus externus. It gives attachment to an inter-muscular septum,
which separates the muscles on the anterior surface from those on the external.
The internal border or interosseous ridge, is situated close to the inner
side of the preceding, it runs nearly parallel with it in the upper third of its
extent, but diverges from it so as to include a broader space in the lower two-
thirds. It commences above just beneath the head of the bone (sometimes it is quite
indistinct for about an inch below the head), and terminates below at the apex of a
rough triangular surface immediately above the articular facet of the external mal-
leolus. It serves for the attachment of the interosseous membrane, and separates
the extensor muscles in front, from the flexor muscles behind. The portion of bone
included between the anterior and interosseous lines, forms the anterior surface.
The posterior border is sharp and prominent; it commences above at the base of
the styloid process, and terminates below in the posterior border of the outer mal-
leolus. It is directed outwards above, backwards in the middle of its course,
backwards and a little inwards below, and gives attachment to an aponeurosis
which separates the muscles on the outer from those on the inner surface of the shaft.
The portion of bone included bet-v^een this line and the interosseous ridge, forms
the internal surface. Its upper three-fourths are subdivided into two parts, an
anterior and a posterior, by a very prominent ridge, the oblique line of the tibia,
which commences above at the inner side of the head, and terminates by being
continuous with the interosseous ridge at the lower fourth of the bone. It attaches
an aponeurosis which separates the Tibialis posticus from the Soleus above, and
the Flexor longus poUicis below. This ridge sometimes ceases just before
approaching the interosseous ridge.
The anterior surface is the interval between the anterior and interosseous lines.
It is extremely narrow and flat in the upper third of its extent; broader and grooved
longitudinally in its lower third ; it serves for the attachment of three muscles, the
Extensor longus digitorum, Peroneus tertius, and Extensor longus pollicis.
The external surface, much broader than the preceding, is directed outwards in
the upper two-thirds of its course, backwards in the lower third, where it is con-
tinuous with the posterior border of the external malleolus. This surface is com-
pletely occupied by the Peroneus longus and brevis muscles.
The internal surface is the interval between the interosseous ridge and the
posterior border, and occupies nearly two-thirds of the circumference of the bone.
Its upper three-fourths are divided into an anterior and a posterior portion by a
very prominent ridge already mentioned, the oblique line of the fibula. The
anterior portion is directed inwards, and is grooved for the attachment of the
Tibialis posticus muscle. The posterior portion is continuous below with the
rough triangular surface above the articular facet of the outer malleolus; it is
directed backwards above, backwards and inwards at its middle, directly inwards
below. Its upper fourth is rough, for the attachment of the Soleus muscle; its
lower part presents a triangular rough surface, connected to the tibia by a strong
interosseous ligament, and between these two points", the entire surface is covered
by the fibres of origin of the Flexor longus pollicis muscle. At about the middle
of this surface is the nutritious foramen, which is directed downwards.
122
OSTEOLOGY.
95
Fibula.
v~ about lil'}y.^r^^\
'Pnttos about 26 ^'iiV.
In order to distinguish the side to which the bone belongs, hold it with the
m ..,1 T-w 1 J. i?j.T. lower extremity downwards, and the broad groove
— Plan of the Development of the „ ,, -r» . , t n i t , -^ ,-,
j^„ Three Centres. ^^^ ^^^ ir^eronei tendons backwards, towards the
holder, the triangular sub-cutaneous surface will
then be directed to theside to which thebone belongs.
Articulations. With two bones; the tibia and
astragalus.
Development. By three centres (fig. 95); one
for the shaft, and one for each extremity. Ossi-
fication commences in the shaft about the sixth
week of foetal life, a little later than in the tibia,
and extends gradually towards the extremities.
At birth both ends are cartilaginous. Ossification
commences in the lower end in the second year,
and in the upper one about the fourth year.
The lower epiphysis, the first in which ossification
commences, becomes united to the shaft about the
twentieth year, contrary to the law which appears
to prevail with regard to the junction of the
epiphyses with the shaft; the upper one is joined
about the twenty-fifth year.
Attachment of Muscles. To the head, the
Biceps, Soleus, and Peroneus longus: to the shaft,
its anterior surface, the Extensor longus digito-
» rum, Peroneus ;tertius, and Extensor longus pol-
licis: to the internal surface, the Soleus, Tibialis
posticus, and Flexor longus pollicis: to the exter-
nal surface, the Peroneus longus and brevis.
Appears aiZ V4ij^
THE FOOT.
The Foot (fig. 96, 97) is the terminal part of the inferior extremity; it serves to
support the body in the erect posture, and as an important instrument of locomo-
tion. It consists of three divisions: the Tarsus, Metatarsus, and Phalanges.
The Tarsus.
The bones of the Tarsus are seven in number; viz., the calcaneum, or os calcis,
astragalus, cuboid, scaphoid, internal, middle, and external, cuneiform bones.
These bones may be conveniently arranged into two lateral rows. The outer
row, remarkable for its great solidity and strength, forms the basis of support to
the foot; it consists of two bones, the os calcis and cuboid. The inner row, which
contributes chiefly to its elasticity, is formed by the astragalus, scaphoid, and three
cuneiform bones.
The Calcaneum.
The Calcaneum, or Os Calcis, is the largest bone of the tarsus. It is irregu-
larly cuboidal in form, and situated at the lower and back part of the foot. It
presents for examination six surfaces; superior, inferior, external, internal, ante-
rior, and posterior.
The superior surface is formed behind, of the upper edge of that process of the
OS calcis which projects backwards to foi-m the heel. This process varies in
length in different individuals; it is convex from side to side, concave from before
backwards, and corresponds above to a mass of adipose substance placed in front
of the tendo Achillis. In the middle of this surface are two (sometimes three)
articular facets, separated by a broad shallow groove, directed obliquely for-
wards and outwards, and rough for the attachment of the interosseous ligament
connecting the astragalus and os calcis. Of these two articular surfaces, the
TARSUS.
96.— Bones of the Right Foot. Dorsal Surface.
123
Grotyv^ far peromeus loncus
GhaOl'R fav PERONEUS BREVIS — V _ "^tei
PERONEUS TERTIU
PERONEUS BREVIS
C-roove for TCTi-oton, of
rLEXOB CONCaS POU.1CIS
Ta^rsus
Meta/t£Lrsws
Iiimr'niost tendon of
EXT.BREVIS OICITORUM
PJtojZcu'rvges
EXT.LONCUS POLLICIS
124 OSTEOLOGY. (j^
external is the larger, and situated upon the body of the bone; it is of an oblong
form, broader behind than in front, and convex from before backwards. The
infernal articular surface is supported on a projecting process of bone, called the
lesser process of the calcaneum (sustentaculum tali) ; it is of an oblong form, con-
cave longitudinally, and sometimes subdivided into two, which differ in size and
shape. More anteriorly is seen the upper surface of the greater process, marked
by a rough depression for the attachment of numerous ligaments, and the tendon
of origin of the Extensor brevis digitorum muscle.
The inferior surface is narrow, rough, uneven, broader behind than in front,
and convex from side to side ; it is bounded posteriorly by two tuberosities,
separated by a rough depression : the external, small, prominent, and rounded,
gives attachment to part of the Abductor minimi digiti; the internal, broader and
larger, for the support of the heel, gives attachment, by its prominent inner
margin, to the Abductor pollicis, and in front to the Flexor brevis digitorum
muscles, and the depression between the tubercles to the Abductor minimi digiti,
and plantar fascia. The rough surface in front of these tubercles gives attach-
ment to the long plantar ligament; and to a prominent tubercle nearer the anterior
part of the bone,. as well as to the transverse groove in front, is attached the short
plantar ligament.
The external surface is subcutaneous, and presents near its centre a tuber-
cle, for the attachment of the middle fasciculus of the external lateral liga-
ment. Behind the tubercle is a broad smooth surface, giving attachment, at its
upper and anterior part, to the external astragalo-calcanean ligament ; and in
front a narrow surface marked by two oblique grooves, separated by an elevated
ridge: the superior groove transmits the tendon Qf the Peroneus brevis; the infe-
rior, the tendon of the Peroneus longus; the intervening ridge gives attachment
to a prolongation from the external annular ligament.
The internal surface presents a deep concavity, directed obliquely downwards
and forwards, for the transmission of the plantar vessels and nerves and Flexor
tendons into the sole of the foot; it affords attachment to part of the Flexor
accessorius muscle. This surface presents in front an eminence of bone, the
lesser process, which projects horizontally inwards from the upper and front part
of this surface. This process is concave above, and supports the anterior articu-
lar surface of the astragalus; below, it is convex, and grooved for the tendon of
the Flexor longus pollicis. Its free margin is rough, for the attachment of liga-
ments.
The anterior surface, of a somewhat triangular form, is smooth, concavo-con-
vex, and articulates with the cuboid. It is surmounted, on its outer side, by a
rough prominence, which forms an important guide to the surgeon in the per-
formance of Chopart's operation.
The posterior surface is rough, prominent, convex, and wider below than
above. Its lower part is rough, for the attachment of the tendo Achillis; its
upper part smooth, coated with cartilage, and corresponds to a bursa which
separates this tendon from the bone.
Articulations. With two bones: the astragalus and cuboid.
Attachment of Muscles. Part of the Tibialis posticus, the tendo Achillis, Plan-
taris. Abductor pollicis. Abductor minimi digiti. Flexor brevis digitorum. Flexor
accessorius, and Extensor brevis digitorum.
The Cuboid.
The Cuboid bone is placed on the outer side of the foot, immediately in front
of the OS calcis. It is of a pyramidal shape, its base being directed upwards and
inwards, its apex downwards and outwards. It may always be known from all
the other tarsal bones, by the existence of a deep grove on its under surface, for
the tendon of the Peroneus longus muscle. It presents for examination six sur-
faces; three articular, and three non-articular: the non-articular surfaces are the
superior, inferior, and external.
I
TARSUS. 125
The superior or dorsal surface, directed upwards and outwards, is rough, for
the attacluiient of numerous ligaments. The inferior or plantar surface presents
in front a deep groove, which runs obliquely from without, forwards and inwards;
it lodges the tendon of the Peroneus longus, and is bounded behind by a promi-
nent ridge, terminating externally in an eminence, the tuberosity of the cuboid,
the surface of which presents a convex facet, for articulation with the sesamoid
bone of the tendon contained in the groove. The ridge and surface of bone
behind it are rough, for the attachment of the long and short plantar ligaments.
The external surface, the smallest and narrowest of the three, presents a deep
notch, formed by the commencement of the peroneal groove.
The articular surfaces are the posterior, anterior, and internal. The posterior
is a smooth, triangular, concavo-convex surface, for articulation with the anterior
surface of the os calcis. The anterior, of smaller size, but also irregularly trian-
gular, is divided by a vertical ridge into two facets; the inner quadrilateral in
form, to articulate with the fourth metatarsal bone; the outer larger and more
triangular, for articulation with the fifth metatarsal. The internal surface is
broad, rough, irregularly quadrilateral, presenting at its middle and upper part a
small oval facet, for articulation with the external cuneiform bone; and behind
this (occasionally) a smaller facet, for articulation with the scaphoid; it is rough
in the rest of its extent, for the attachment of strong interosseous ligaments.
To ascertain to which foot it belongs, hold the bone so that its under surface,
marked by the peroneal groove, looks downwards, and the large concavo-convex
articular surface backwards, towards the holder; the small non-articular surface
marked by the commencement of the peroneal groove, will point to the side to
which the bone belongs.
Articulations. With four bones: the os calcis, external cuneiform, and the
fourth and fifth metatarsal bones, occasionally with the scaphoid.
Attachment of Muscles. Part of the Flexor brevis pollicis.
The Astragalus.
The Astragalus (fig. 96), next to the os calcis, is the largest of the tarsal bones.
It is placed at the middle and upper part of the tarsus, supporting the tibia above,
articulating with the malleoli on either side, resting below upon the os calcis, and
joined in front to the scaphoid. This bone may easily be recognised by its large
rounded head, the broad articular facet on its upper convex surface, and by the
two articular facets separated by a deep groove on its under concave surface. It
presents six surfaces for examination.
The superior surface presents, behind, a broad smooth trochlear surface, for
articulation with the tibia; it is broader in front than behind, convex from be-
fore backwards, slightly concave from side to side. In front of the trochlea
is the upper surface of the neck of the astragalus, rough for the attachment of
ligaments. The inferior surface presents two articular facets separated by a deep
groove. The groove runs obliquely forwards and outwards, becoming gradually
broader and deeper in front: it corresponds with a similar groove upon the upper
surface of the os calcis, and forms, when articulated with that bone, a canal, filled
up in the recent state by the calcaneo-astragaloid interosseous ligament. Of the
two articular facets, the posterior is the larger, of an oblong form, and deeply
concave from side to side; the anterior, although nearly of equal length, is nar-
rower, of an elongated oval form, convex from side to side, and often subdivided
into two by an elevated ridge; the posterior articulates with the lesser process of
the 0^ calcis; the anterior, with the upper surface of the calcaneo-scaphoid ligament.
The internal surface presents at its upper part a pear-shaped articular facet for the
inner malleolus, continuous above with the trochlear surface; below the articular sur-
face is a rough depression, for the attachment of the deep portion of the internal
lateral ligament. The external surface presents a large triangular facet, concave
from aljove downwards, for articulation with the external malleolus; it is con-
126
OSTEOLOGY.
97. — Bones of the Eight Foot. Plantar Surface.
fLEXOR BREVIS POtllCIS
Tulierch: of
Sfeajpkoid
TIBIALIS ANTICUSI
/' FLEXOR 8i7EVIS
J & ABDUCTOR
(^ MiniMI DICITI
FLEXOR LONCUS
\/ QICITORUM
TARSUS.
127
tinuous above with the trochlear surface: in front is a deep rough margin, for the
attachment of the anterior fasciculus of the external lateral ligament. The
anterior surface, convex and rounded, forms the head of the astragalus; it is
smooth, of an oval form, and directed obliquely inwards and downwards; it is
continuous below with that part of the anterior facet on the under surface which
rests upon the calcaneo-scaphoid ligament. The head is surrounded by a con-
stricted portion, the neck of the astragalus. The posterior surface is narrow, and
traversed by a groove, which runs obliquely downwards and inwards, and trans-
mits the tendon of the Flexor longus pollicis.
To ascertain to which foot it belongs, hold the bone with the broad articular
surface upwards, and the rounded head forwards; the lateral triangular articular
surface for the external malleolus will then point to the side to which the bone
belongs.
Articulations. With four bones; tibia, fibula, os calcis, and scaphoid.
The Scaphoid.
The Scaphoid or Navicular bone, so called from its fancied resemblance to a
boat, is situated at the inner side of the tarsus, between the astragalus behind and
the three cuneiform bones in front. This bone may be distinguished by its boat-
like form, being concave behind, convex, and subdivided into three facets in
front.
The anterior surface, of an oblong from, is convex from side to side, and sub-
divided by two ridges into three facets, for articulation with the three cuneiform
bones. The posterior surface is oval, concave, broader externally than internally,
and articulates with the rounded head of the astragalus. The superior surface is
convex from side to side, and rough for the attachment of ligaments. The
inferior, somewhat concave, irregular, and also rough for the attachment of
ligaments. The internal surface presents a rounded tubercular eminence, the
tuberosity of the scaphoid, which gives attachment to part of the tendon of the
Tibialis posticus. The external surface is broad, rough, and irregular, for the
attachment of ligamentous fibres, and occasionally presents a small facet for articu-
lation with the cuboid bone.
To ascertain to which foot it belongs, hold the bone with the concave articular
surface backwards, and the broad dorsal surface upwards; the broad external
surface will point to the side to which the bone belongs.
Articulations. With four bones; astragalus and three cuneiform; occasionally
also with the cuboid.
Attachment of Muscles. Part of the Tibialis posticus.
The Cuneiform Bones have received their name from their wedge-like form.
They form the most anterior row of the inner division of the tarsus, being placed
between the scaphoid behind, the three innermost metatarsal bones in front, and
the cuboid externally. They are called ihe first, second, and third, counting from
the inner to the outer side of the foot, and from their position, internal, middle,
and external.
The Internal Cuneiform.
The Internal Cuneiform is the largest of the three. It is situated at the inner
side of the foot, between the scaphoid behind and the base of the first metatarsal
in front. It may be distinguished by its large size, as compared with the other
two, and from its more irregular wedge-like form. It presents for examination
six surfaces.
The internal surface is subcutaneous, and forms part of the inner border of the
foot; it is broad, quadrilateral, and presents at its anterior inferior angle a smooth
oval facet, over which the tendon of the Tibialis anticus muscle glides; rough in
the rest of its extent, for the attachment of ligaments. The external surface is
concave, presenting, along its superior and posterioi- borders, a narrow surface for
articulation with the middle cuneiform behind, and second metatarsal bone in
128 OSTEOLOGY.
front; in the rest of its extent, it is rough for the attachment of ligaments, and
prominent below, where it forms part of the tuberosity. The anterior surface,
reniform in shape, articulates with the metatarsal bone of the great toe. The
posterior surface is tinangular, concave, and articulates with the innermost and
largest of the three facets on the anterior surface of the scaphoid. The inferior
or plantar surface is rough, and presents a prominent tuberosity at its back part
for the attachment of part of the tendon of the Tibialis posticus. It also gives
attachment in front of this to part of the tendon of the Tibialis anticus. The
superior surface is the narrow pointed end of the wedge, which is directed upwai'ds
and outwards ; it is rough for the attachment of ligaments.
To ascertain to which side it belongs, hold the bone so that its superior narrow
edge looks upwards, and the long articular surface forwards; the external surface
marked by its vertical and horizontal articular facets will point to the side to
which it belongs.
Articulations. With four bones; scaphoid, middle cuneiform, and first and
second metatarsul bones.
Attachment of Muscles. The Tibialis anticus and posticus.
The Middle Cuneiform.
The Middle Cuneiform, the smallest of the three, is of very regular wedge-
like form; the broad extremity being placed upwards, the narrow end downwards.
It is situated between the other two bones of the same name, and corresponds to
the scaphoid behind, and the second metatarsal in front.
The anterior surface, triangular in form, and narrower than the posterior, articu-
lates with the base of the second metatarsal bone. The posterior surface, also
triangular, articulates with the scaphoid. The internal surface presents an articular
facet, running along the superior and posterior borders, for articulation with the
internal cuneiform, and is rough below for the attachment of ligaments. The
external surface presents posteriorly a smooth facet for articulation with the
external cuneiform bone. The superior surface forms the base of the wedge ; it
is quadrilateral, broader behind than in front, and rough for the attachment of
ligaments. The inferior surface, pointed and tubercular, is also rough for liga-
mentous attachment.
To ascertain to which foot the bone belongs, hold its superior or dorsal surface
upwards, the broadest edge being towards the holder, and the smooth facet
(limited to the posterior border) will point to the side to which it belongs.
Articulations. With four bones; scaphoid, internal and external cuneiform, and
second metatarsal bone.
The External Cuneiform.
The External Cuneiform, intermediate in size between the two preceding, is of
a very regular wedge-like form, the broad extremity being placed upwards, the
narrow end downwards. It occupies the centre of the front row of the tarsus
between the middle cuneiform internally, the cuboid externally, the scaphoid
behind, and the third metatarsal in front. It has six surfaces for examination.
The anterior surface triangular in form, articulates with the third metatarsal bone.
The posterior surface articulates with the most external facet of the scaphoid, and
is rough below for the attachment of ligamentous fibres. The internal surface pre-
sents two articular facets separated by a rough depression; the anterior one, situated
at the superior angle of the bone, articulates with the outer side of the base of the
second metatarsal bone; the posterior one skirts the posterior border, and articu-
lates with the middle cuneiform; the rough depression between the two gives
attachment to an interosseous ligament. The external surface also presents two
articular facets, separated by a rough non-articular surface; the anterior facet,
situated at the superior corner of the bone, is small, and articulates with the inner
side of the base of the fourth metatarsal; the posterior, and larger one, articulates
METATARSAL BONES. 129
with the cuboid; the rough non-articular surface serves for the attachment of an
interosseous ligament. The three facets for articulation with the three metatarsal
bones are continuous with one another, and covered by a prolongation of the same
cartilage; the facets for articulation with the middle cuneiform and scaphoid are
also continuous, but that for articulation with the cuboid is usually separate and
independent. The superior or dorsal surface, of an oblong form, is rough for the
attachment of ligaments. The inferior or plantar surface is an obtuse rounded
margin, and serves for the attachment of part of the tendon of the Tibialis posticus,
some of the fibres of origin of the Flexor brevis pollicis, and ligaments.
To ascertain to which side it belongs, hold the bone with the broad dorsal sur-
face upwards, the prolonged edge backwards; the separate articular facet for the
cuboid will point to the proper side.
Articulations. With six bones : the scaphoid, middle cuneiform, cuboid, and
second, third, and fourth metatarsal bones.
Attachment of Muscles. Part of Tibialis posticus, and Flexor brevis pollicis.
The Metatarsal Bones.
The Metatarsal bones are five in number; they are long bones, and subdivided
into a shaft, and two extremities.
The Shaft is prismoid in form, tapers gradually from the tarsal to the phalan-
geal extremity, and is slightly curved longitudinally, so as to be concave below,
slightly convex above.
The Posterior Extremity, or Base, is wedge-shaped, articulating by its terminal
surface with the tarsal bones, and by its lateral surfaces with the contiguous bones ;
its dorsal and plantar surfaces being rough, for the attachment of ligaments.
The Anterior Extremity, or Head, presents a terminal rounded articular sur-
face, oblong from above downwards, and extending further backwards below than
above. Its sides are flattened, and present a depression, surmounted by a tuber-
cle, for ligamentous attachment. Its under surface is grooved in the middle line,
for the passage of the Flexor tendon, and marked on each side by an articular
eminence continuous with the terminal articular surface.
Peculiar Metatarsal Bones.
The First is remarkable for its great size, but is the shortest of all the meta-
tarsal bones. The shaft is strong, and of well-marked prismoid form. The
posterior extremity presents no lateral articular facets; its terminal articular sur-
face is of large size, of semi-lunar form, and its circumference grooved for the
tarso-metatarsal ligaments; its inferior angle presents a rough oval prominence,
for the insertion of the tendon of the Peroneus longus. The head is of large size;
on its plantar surface are two grooved facets, over which glide sesamoid bones,
separated by a smooth elevated ridge.
The Second is the longest and largest of the remaining metatarsal bones; its
posterior extremity being prolonged backwards, into the recess formed between
the three cuneiform bones. Its tarsal extremity is broad above, narrow and rough
below. It presents four articular surfaces: one behind, of a triangular form, for
articulation with the middle cuneiform; one at the upper part of its internal
lateral surface, for articulation with the internal cuneiform; and two on its
external lateral surface, a superior and an inferior, separated by a rough depres-
sion. Each articular surface is divided by a vertical ridge into two parts; the
anterior segment of each facet articulates with the third metatarsal; the two pos-
terior (sometimes continuous) with the external cuneiform.
The Third articulates behind, by means of a triangular smooth surface, with
the external cuneiform; on its inner side, by two facets, with the second meta-
tarsal; and on its outer side, by a single facet, with the third metatarsal. This
facet is of circular form, and situated at the upper angle of the base.
K
130 OSTEOLOGY.
The Fourth is smaller in size than the preceding; its tarsal extremity presents
a terminal quadrilateral surface, for articulation with the cuboid; a smooth facet
on the inner side, divided by a ridge into an anterior portion for articulation with
the third metatarsal, and a posterior portion for articulation with the external
cuneiform; on the outer side a single facet, for articulation with the fifth metatarsal.
The Fifth is recognised by the tubercular eminence on the outer side of its
base; it articulates behind, by a triangular surface cut obliquely from without
inwards, with the cuboid, and internally with the fourth metatarsal.
Articulations. Each bone articulates with the tarsal bones by one extremity,
and by the other with the first row of phalanges. The number of tarsal bones
with which each metatarsal articulates, is one for the first, three for the second,
one for the third, two for the fourth, and one for the fifth.
Attachment of Muscles. To the first metatarsal bone, three: part of the Tibialis
anticus, Peroneus longus, and First dorsal interosseous. To the second, three:
the Adductor pollicis, and First and Second dorsal interosseous. To the third,
four : the Adductor pollicis. Second and Third dorsal interosseous, and First
plantar. To the fourth, four: the Adductor pollicis. Third and Fourth dorsal,
and Second plantar interosseous. To the fifth, five: the Peroneus brevis, Pero-
neus tertius. Flexor brevis minimi digiti. Fourth dorsal, and Third plantar inter-
osseous.
Phalanges.
The Phalanges of the foot, both in number and general arrangement, resemble
those in the hand; there being two in the great toe, and three in each of the
other toes.
The phalanges of the first row resemble closely those of the hand. The shaft
is compressed from side to side, convex above, concave below. The posterior
extremity is concave ; and the anterior extremity presents a trochlear-articular
surface, for articulation with the second phalanges.
The phalanges of the second roio are remarkably small and short, but rather
broader than those of the first row.
The ungual phalanges in form resemble those of the fingers; but they are
smaller, flattened from above downwards, presenting a broad base for articulation
with the second row, and an expanded extremity for the support of the nail and
end of the toe.
Articulations. The first row with the metatarsal bones, and second phalanges;
the second of the great toe with the first phalanx, and of the other toes with the
first and third phalanges; the third with the second row.
Attachment of Muscles. To the first phalanges, gi'eat toe: innermost tendon of
Extensor brevis digitorum. Abductor pollicis. Adductor pollicis, Flexor brevis
pollicis, Transversus pedis. Second toe: First and Second dorsal interosseae.
Third toe: Third dorsal and First plantar interosseae. Fourth toe: Fourth dor-
sal and Second plantar interossese. Fifth toe : Flexor brevis minimi digiti,
Abductor minimi digiti, and Third plantar interosseous. — Second phalanges,
great toe : Extensor longus pollicis. Flexor longus pollicis. Other toes : Flexor
brevis digitorum, one slip from the Extensor brevis digitorum and Extensor longus
digitorum. — Third phalanges: two slips from the common tendon of the Extensor
longus and Extensor brevis digitorum, and the Flexor longus digitorum.
Development of the Foot. (Fig. 98.)
The Tarsal bones are each developed by a single centre, excepting the os calcis,
which has an epiphysis for its posterior extremity. The centres make their
appearance in the following order: in the os calcis, at the sixth month of foetal
life ; in the astragalus, about the seventh month ; in the cuboid, at the ninth
month; external cuneiform, during the first year; internal cuneiform, in the third
year ; middle cuneiform, in the fourth year. The epiphysis for the posterior
SESAMOID BONES.
131
tuberosity of the os calcis appears at the tenth year, and unites with the rest of
the bone soon after puberty.
The Metatarsal bones are each developed by tioo centres: one for the shaft,
and one for the digital extremity in the four outer metatarsal; one for the shaft,
and one for the base in the metatarsal bone of the great toe. Ossification
98. — Plan of the Development of the Foot.
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commences in the centre of the shaft about the seventh week, and extends towards
either extremity, and in the digital epiphyses about the third year; they become
joined between the eighteenth and tAventieth years.
The Phalanges are developed by two centres for each bone: one for the shaft,
and one for the metatarsal extremity.
Sesamoid Bones.
These are small rounded masses, cartilaginous in early life, osseous in the
adult, which are developed in those tendons which exert a certain amount of
pressure upon the parts over which they glide. It is said that they are more
commonly found in the male than in the female, and in persons of an active mus-
cular habit than in those that are weak and debilitated. They are invested
throughout their whole surface by the fibrous tissue of the tendon in which they
are found, excepting upon that side which lies in contact with the part over which
they play, where they present a free articular facet. They may be divided into
K 2
132 OSTEOLOGY.
two kinds: those which glide over the articular surfaces of joints; those which
play over the cartilaginous facets found on the surfaces of certain bones.
The sesamoid bones of the joints are, in the lower extremity, the patella (already
described), which is developed in the tendon of the Quadriceps extensor. Two
small sesamoid bones are found opposite the metatarso-phalangeal joint of the
great toe in each foot, in the tendons of the Flexor brevis poUicis, and occasionally
one in the metatarso-phalangeal joints of the second toe, the little toe, and, still
more rarely, in the third and fourth toes.
In the upper extremity, there are two on the palmar surface, opposite the meta-
carpo-phalangeal joint in the thumb, developed in the tendons of the Flexor brevis
pollicis. Occasionally one or two opposite the metacarpo-phalangeal articulations
of the fore and little fingers, and, still more rarely^, one opposite the same joints of
the third and fourth fingers.
Those found in tendons which glide over certain bones occupy the following
situations. One in the tendon of the Peroneus longus, where it glides through the
groove in the cuboid bone. One appears late in life in the tendon of the Tibialis
anticus, opposite the smooth facet on the internal cuneiform bone. One in the
tendon of the Tibialis posticus, opposite the inner side of the astragalus. One in
the outer head of the Gastrocnemius, behind the outer condyle of the femur; and
one in the Psoas and Iliacus, where they glide over the body of the pubes. Occa-
sionally in the tendon of the Biceps, opposite the tuberosity of the radius; in the
tendon of the Gluteus maximus, as it passes over the great trochanter; and in the
tendons which wind around the inner and outer malleoli.
The Articulations.
THE various bones of which the Skeleton consists are connected together at
different parts of their surfaces, and such connection is designated by the
name of Joint or Articulation. If the joint is immoveable, as between the cranial
bones, their adjacent margins are applied in almost close contact, a thin layer of
fibrous membrane only being interj)osed; but in the moveable joints, the bones
forming the articulation are generally expanded for greater convenience of mutual
connexion, covered by an elastic structure, called cartilage, held together by strong
bands, or capsules, of fibrous tissue, called ligament, and lined throughout by a
membrane, the synovial membrane, which secretes a fluid which lubricates the
various parts of which the joint is formed, so that the structures which enter
into the formation of a joint are bone, cartilage, fibro- cartilage, ligament, and
synovial membrane.
Bone constitutes the fundamental element of all the joints. In the long bones
the extremities are the parts which form the articulations; they are generally some-
what enlarged and expanded, consisting of loose spongy cancellous tissue, with a
thin coating of compact substance, which forms their articular surface, and is
called the articular lamella. In the flat bones, the articulations usually take
place at the edges; and in the short bones, by various parts of their surface.
Cartilage is a firm, opaque, blueish-white substance, highly elastic, extremely
flexible, and possessed of considerable cohesive power. That form of cartilage
which enters into the formation of the joints is called articular cartilage; it forms
a thin incrustation upon the articular extremities, or surfaces, of bones, and is
admirably adapted, by its elastic property, to break the force of concussions, and
afford perfect ease and freedom of movement between the bones. Where it covers
the rounded ends of bones, as the extremities of the femur and humerus, it is thick
at the centre, and becomes gradually thinner towards the circumference: an oppo-
site arrangement exists where it lines the corresponding cavities. On the articular
surfaces of the short bones, as the carpus and tarsus, the cartilage is disposed in a
layer of uniform thickness throughout. The attached surface of articular cartilage
is closely adapted to the articular lamella; the free surface is smooth, polished,
and covered in the fcetus by an extremely thin prolongation of synovial membrane,
which, however, at a later period of life, cannot be demonstrated. Articular car-
tilage in the adult does not contain blood-vessels; its nutrition being derived from
the vessels of the synovial membrane which skirt the circumference of the carti-
lage, and from those of the adjacent bone, which are, however, separated from direct
contact with the cartilage by means of the articular lamella. Mr. Toynbee has
shown, that the minute vessels as they approach the articular lamella dilate, and
forming arches, return into the cancellous tissue of the bone. The vessels of the
synovial membrane advance forwards with it upon the circumference of the carti-
lage for a very short distance, and then return in loops; they are only found on the
parts not subjected to pressure. In the fcetus, and also in certain diseased condi-
tions of the joints, the vessels advance for some distance upon the cartilage. Lym-
phatic vessels and nerves have not, as yet, been traced in its substance.
Fibro-cartilage is also employed in the construction of the joints, contributing
to their strength and elasticity. This consists of a mixture of white fibrous and
cartilaginous tissues in various proportions; it is to the first of these two consti-
tuents that its strength and toughness is chiefly owing and to the latter Its elas-
ticity. The fibro-cartilages admit of arrangement into four groups, inter-articular,
inter-osseous, circumferential, and stratiform.
The Inter-articular fibro-cartilages {menisci) are flattened fibro-cartilaginous
plates, of a round, oval, or sickle-like form, interposed between the articular sur-
134 ARTICULATIONS.
faces of certain joints. They are free on both surfaces, thinner toward their
centre than at their circumference, and held in position by their exti-emities being
connected to the surrounding ligaments. The synovial membrane of the joint is
prolonged over them a short distance from their attached margin. They are found
in the temporo-maxillary, sterno-clavicular, acromio-clavicular, wrist and knee
joints.
The Inter-osseous fibro-cartilages are interposed between the bony surfaces of
those joints which admit of only slight mobility, as between the bodies of the
rertebrse and the symphysis of the pubes; they exist in the form of discs, inti-
mately adherent to the opposed surfaces, being composed of concentric rings of
fibrous tissue, with cartilaginous laminae interposed, the former tissue predomi-
nating towards the circumference, the latter towards the centre.
The Circumferential fihro-cartilages consist of a rim of fibro-cartilage, which
surrounds the margins of some of the articular cavities, as the cotyloid cavity of
the hip, and the glenoid cavity of the shoulder ; they serve to deepen the articular
surface and protect the edges of the bone.
The Stratiform fihro-cartilages are those which form a thin layer in the osseous
grooves, through which the tendons of certain muscles glide.
Ligaments are found in nearly all the moveable articulations; they consist of
bands of various forms, serving to connect together the articular extremities of
bones, and composed mainly of bundles of white fibrous tissue, placed parallel with,
or closely interlaced with, one another, and presenting a white, shining, silvery
aspect. Ligament is pliant and flexible, so as to allow of the most perfect freedom
of movement, but strong, tough, and inextensile, so as not readily to yield under the
most severely applied force; it is, consequently, admirably adapted to serve as the
connecting medium between the bones. There, are some ligaments which consist
entirely of yellow elastic tissue, as the ligamenta subflava, which connect together
the adjacent arches of the vertebrae.
Synovial Membrane is a thin, delicate membrane, which invests the arti-
cular extremities of the bones, and is then reflected on the inner surface of the
various ligaments which connect the articulating surfaces. It resembles the serous
membrane in being a shut sac, but difiers in the nature of its secretion, which is
thick, viscid, and glairy, like the white of egg ; and hence termed synovia. The
synovial membranes found in the body admit of subdivision into three kinds,
articular, bursal, and vaginal.
The Articular Synovial Membranes are found in all the freely moveable
(diarthrodial) joints. In the foetus, this membrane may be traced over the entire
surface of the cartilages; but in the adult it is wanting, excepting at their circum-
ference, upon which it encroaches for a short distance: it then invests the inner
surface of the capsular or other ligaments enclosing the joint, and is reflected over
the surface of any tendons passing through its cavity, as the tendon of the Popli-
teus in the knee, and the tendon of the Biceps in the shoulder. In some joints,
the synovial membrane is thrown into numerous folds, which project forward into
the cavity. These folds consist of a reduplication of the synovial membrane, some
of them containing fat, and, more rarely, isolated cartilage-cells; the free borders
of the longer processes being subdivided into vascular fringe-like processes, the
vessels of which have a convoluted arrangement. They are especially distinct in
the knee, where they are known as the mucous and alar ligaments, and were
described by Clop ton Havers as mucilaginous glands, and as the source of the
synovial secretion, a view lately revived by Mr. Eainey, who finds them in the
bursal and vaginal, as well as in the articular synovial membranes.
The Bursal Synovial Membranes {Burses mucosce) are found interposed be-
tween surfaces which move upon each other, producing friction, as in the gliding
of a tendon, or of the integument over projecting bony surfaces. They are small
shut sacs, connected by areolar tissue with the adjacent parts, and secreting a
fluid in their interior analogous to synovia. The bursse admit of a subdivision
into two kinds, subcutaneous and deep-seated. The subcutaneous are found in
STRUCTURE OF JOINTS.
135
various situations, as between the integument and front of the patella, over the
olecranon, the malleoli, and other prominent parts. The deep seated are more
numerous, and usually found interposed between muscles or their tendons as they
play over projecting bony surfaces, as between the Glutei muscles and surface of
the gi-eat trochanter. Where one of these exists in the neighbourhood of a joint,
it usually communicates with the cavity of the synovial membrane, as is generally the
case with the bursa between the tendon of the Psoas and Iliacus, and the capsular
ligament of the hip, or the one interposed between the under surface of the Sub-
scapularis and the neck of the scapula.
The Vaginal Synovial Membranes (synovial sheaths) serve to facilitate the
gliding of tendons in the osseo-fibrous canals through which they pass. The
membrane is here arranged in the form of a sheath, one layer of which adheres to
the wall of the canal, and the other is reflected upon the outer surface of the con-
tained tendon; the space between the two free surfaces of the membrane, being
partially filled with synovia. These sheaths are chiefly found surrounding the
tendons of the Flexor and Extensor muscles of the fingers and toes, as they pass
through the osseo-fibrous canals in the hand or foot.
Synovia is a transparent, yellowish-white, or slightly reddish fluid, viscid like
the white of Qgg, having an alkaline reaction, and slightly saline taste. It con-
sists, according to Frerichs, in the ox, of 94*85 water, o"56 mucus and epithelium,
0*07 fat, 3'5i albumen and extractive matter, and 0*99 salts.
The Articulations are divided into three classes: Synarthrosis, or immoveable;
Amphiarthrosis, or mixed; and Diarthrosis, or moveable,
I. Synarthrosis. Lmmoveable Articulations.
Synarthrosis {crvv, with, apOpov, a joint), or Immoveable Joints, include all those
articulations in which the surfaces of the bones are in almost direct contact, not se-
parated by an intervening synovial cavity, and immoveably connected with each
other, as between the bones of the cranium and face, excepting the lower jaw.
The varieties of synarthrosis are three in number: Sutura, Schindylesis, Gomphosis.
Sutura (a seam). Where the articulating surfaces are connected by a series
of processes and indentations interlocked together, it is termed sutura vera; of
which there are three varieties: sutura dentata, serrata, and limbosa. The sur-
faces of the bones are not in direct contact, being separated by a layer of mem-
brane continuous externally with the pericranium, internally with the dura mater.
The sutura dentata {dens, a tooth) is so called from the tooth-like form of the
projecting articular processes, as in the suture between the parietal bones. In
the sutura serrata {serra, a saw), the edges of the two bones forming the arti-
culation are serrated like the teeth of a fine saw, as between the two portions of
the frontal bone. In the sutura limbosa {limbus, a selvage), besides the den-
tated processes, there is a certain degree of bevelling of the articular surfaces, sc
that the bones overlap one another, as in the suture between the parietal and
occipital bones. Where the articulation is formed by roughened surfaces placed
in apposition with one another, it is termed the false suture, sutura notha, of
which there are two kinds: the sutura squamosa {squama, a scale), formed by
the overlapping of two contiguous bones by broad bevelled margins, as in the
temporo-parietal suture; and the sutura harmonia {apeiv, to adapt), where there
is simple apposition of two contiguous rough bony surfaces, as in the articulation
between the two superior maxillaiy bones, or of the palate processes of the palate
bones with each other. The sutures present a great tendency to obliteration as
age advances, the intervening fibrous-tissue becoming ossified. The frontal suture
seldom exists after puberty; and it rarely happens that all the others are distinct
in a skull beyond the age of fifty.
Schindylesis {<T')(^ivSv\rjac^, a fissure) is that form of articulation in which a
thin plate of bone is received into a cleft or fissure formed by the separation of
two laminge of another, as in the articulation of the rostrum of the sphenoid,
and descending plate of the ethmoid with the vomer, or in the reception of the
latter in the fissure between the superior maxillary and palate bones.
136 ARTICULATIONS.
Gomphosis (<yo/x(l>o<;, a nail) is an articulation formed by the insertion of a
conical process into a socket, as a nail is driven into a board; and is illustrated in
the articulation of the teeth in the alveoli of the maxillary bones.
2. Amphiarthrosis. Mixed Articulations.
Amp Mar thro sis (a//.<^4 'on all sides,' apOpov a 'joint'), or Mixed Articulation.
In this form of articulation, the contiguous osseous surfaces are connected together
by broad flattened discs of fibro- cartilage, which adhere to the ends of both bones,
as in the articulation between the bodies of the vertebrae, and first two pieces of
the sternum; or the articulating surfaces are covered with fibro-cartilage, lined by
a partial synovial membrane, and connected together by external ligaments, as in
the sacro-iliac and pubic symphyses; both these forms being capable of limited
motion in every direction. The former resemble the synarthrodia! joints in the
continuity of their surfaces, and absence of synovial sac; the latter, the diarthro-
dial. These joints occasionally become obliterated in old age: this is frequently
the case in the inter-pubic articulation, and occasionally in the intervertebral and
sacro-iliac.
3, Diarthrosis. Moveable Articulations.
Diarthrosis (Sia 'through,' apOpov 'a joint'). This form of articulation
includes the greater number of the joints in the body, mobility being their dis-
tinguishing character. They are formed by the approximation of two contiguous
bony surfaces, covered with cartilage, connected by ligaments, and having a syno-
vial sac interposed. The varieties of joints in this class, have been determined
by the kind of motion permitted in each; they are four in number: Arthrodia,
Enarthrosis, Ginglymus, Diarthrosis Rotatorius.,
Arthrodia is that form of joint which admits of a gliding movement; it is
formed by the approximation of plane surfaces, or one slightly concave, the other
slightly convex; the amount of motion between them being limited by the liga-
ments, or osseous processes, surrounding the articulation; as in the articular pro-
cesses of the vertebrae, temporo-maxillary, sterno and acromio-clavicular, inferior
radio-ulnar, carpal, carpo-metacarpal, superior tibio-fibular, tarsal, and tarso-meta-
tarsal articulations.
Enarthrosis is that form of joint which is capable of motion in all directions.
It is formed by the reception of a globular head into a deep cup-like cavity (hence
the name ' ball and socket '), the parts being kept in apposition by a capsular
ligament strengthened by accessory ligamentous bands, and the contiguous carti-
laginous surfaces having a synovial sac interposed. Examples of this form of
articulation are found in the hip and shoulder-joints.
Ginglymus, Hinge-joint {jL'yyXv/jiO'i, a hinge). In this form of joint, the
articular surfaces are moulded to each other in such a manner, as to permit
motion only in one direction, forwards and backwards, the extent of motion at the
same time being considerable. The articular surfaces are connected together by
strong lateral ligaments, which form their chief bond of union. The most
perfect forms of ginglymi are the elbow and ankle; the knee is less perfect, as it
allows a slight degree of rotation in certain positions of the limb: there are also
the metatarso-phalangeal and phalangeal joints in the lower extremity, metacarpo-
phalangeal and phalangeal joints in the upper extremity.
Diarthrosis rotatorius (Lateral G-inglymus). Where the mobility is limited to rota-
tion, the joint is formed by a pivot-like process turning within a ring, or the ring
on the pivot, the ring being formed partly of bone, partly of ligament. In the ar-
ticulation of the odontoid process of the axis with the atlas, the ring is formed in
front by the anterior arch of the atlas; behind, by the transverse ligament; here the
ring rotates around the odontoid process. In the superior radio-ulnar articulation,
the ring is formed partly by the lesser sigmoid cavity of the ulna; in the rest of its
extent, by the orbicular ligament; here, the neck of the radius rotates within the
ring.
SUBDIVISION INTO THREE CLASSES.
137
Subjoined, in a tabular form, are the names, distinctive characters, and examples
of the different kinds of articulations.
Dentata, having
tooth-like processes.
Inter-parietal su-
ture.
Serrata, having
serrated edges, like
the teeth of a saw.
Inter-frontal su-
ture.
Limbosa, having
bevelled margins,
and dentated pro-
cesses.
Occipito - parietal
suture.
Synarthrosis, or
immoveable joint.
Surfaces separated
by fibrous membrane,
no intervening syno-
vial cavity, and im-
moveably connected
with each other.
Example: bones of
cranium and face
(except lower jaw).
Sutura. Arti-
culation by pro-
cesses and indent-
ations interlocked
toarether.
Sutura vera
(true) articulate
by indented bor-
ders.
Sutura notha
(false) articulate <
^ by rough surfaces
Squamosa,^OTXXMe,dL
by thin bevelled mar-
gins overlapping
each other.
Temporo - parietal
suture.
Harmonia, formed
by the apposition of
contiguous rough
surfaces.
Inter-maxillary su-
^ture.
Schindylesis. Articulation formed by the reception of , a
thin plate of bone into a fissure of another.
Rostrum of sphenoid with vomer.
Gomphosis. An articulation formed by the insertion of a
conical process into a socket.
Tooth in socket.
Amphiarthrosis,
Mixed Articulation,
Diarthrosis,
Moveable Joint.
11. Surfaces connected by fibro-cartilage, not separated by
synovial membrane, and having limited motion. Bodies of
vertebras.
2. Surfaces connected by fibro-cartilage, lined by a partial
synovial membrane. Sacro-iliac and pubic symphyses.
Arthrodia. Gliding joint; articulation by plane surfaces,
which glide upon each other. As in sterno and acromio-
clavicular articulations.
Enarthrosis. Ball and socket joint; capable of motion in
all directions. Articulation by a globular head received into
a cup-like cavity. As in hip and shoulder joints.
Ginglymus. Hinge joint; motion limited to one direction,
forwards and backwards. Articular surfaces fitted together
so as to permit of movement in one plane. As in the elbow,
ankle, and knee.
Diarthrosis rotatorius. Articulation by a pivot process
turning within a ring, or ring "around a pivot. As in supe-
rior radio-ulnar articulation, and atlo-axoid joint.
138 AETICULATIONS.
The Kinds of Movement admitted in Joints.
The movements admissible in joints may' be divided into four kindb, gliding,
angular movement, circumduction, and rotation.
Gliding movement is the most simple kind of motion that can take place in a
joint, one surface gliding over another. This kind of movement is common to all
moveable joints; but in some, as in the articulations of the carpus and tarsus,
is the only motion permitted. This motion is not confined to plane surfaces, but
may exist between any two contiguous surfaces, of whatever form, limited by the
ligaments which enclose the articulation.
Angular movement occurs only between the long bones, and may take place in four
directions, forwards or backwards, constituting flexion and extension, or inwards
and outwards, which constitutes abduction and adduction. Flexion and extension
is confined to the strictly ginglymoid or hinge joints. Abduction and adduction,
combined with flexion and extension, are met with only in the most moveable
joints; as in the hip, shoulder, and thumb, and partially in the wrist and ankle.
Circumduction is that limited degree of motion which takes place between the
head of a bone and its articular cavity, whilst the extremity and sides of a limb
are made to circumscribe a conical space, the base of which corresponds with the
inferior extremity of the limb, the apex to the articular cavity; and is best seen
in the shoulder and hip joints.
Rotation is the movement of a bone upon its own axis, the bone retaining the
same relative situation with respect to the adjacent parts; as in the articulation
between the atlas and axis, where the odontoid process serves as a pivot around
which the atlas turns; or in the rotation of the radius against the humerus, and
also in the hip and shoulder.
The articulations may be arranged into those of the trunk, those of the upper
extremity, and those of the lower extremity.
ARTICULATIONS OF THE TRUNK.
These may be divided into the following groups viz.: — •
1. Of the vertebral column. 7. Of the cartilages of the ribs with the
2. Of the atlas with the axis. sternum, and with each other.
3. Of the atlas with the occipital bone. 8. Of the sternum.
4. Of the axis with the occipital bone. g. Of the vertebral column with the
5. Of the lower jaw. pelvis.
6. Of the ribs with the vertebra. 10. Of the Pelvis.
I. Articulations of the Vertebral Column.
The different segments of the vertebral column are connected together by ligaments,
which admit of the same arrangement as the vertebrae themselves. They may be
divided into five sets, i . Those connecting the bodies of the vertebrae. 2. Those
connecting the lamina. 3. Those connecting the articular processes. 4. The liga-
ments connecting the spinous processes. 5. Those of the transverse processes.
The articulation of the bodies of the vertebrae with each other, form a series of
amphiarthrodial joints; whilst those between the articular processes form a series
of arthrodial joints.
I. The Ligaments of the Bodies are
Anterior Common Ligament. Posterior Common Ligament.
Intervertebral Substance.
The Anterior Common Ligament (fig. 107) is a broad and strong band of ligamen-
tous fibres, which extends along the front surface of the bodies of the vertebrae, from
the axis to the sacrum. It is broader below than above, and thicker in the dorsal
than in the cervical or lumbar regions. It is attached, above, to the body of the
axis by a pointed process, which is connected with the tendon of origin of the
Longus colli muscle; and, as it descends, is somewhat broader opposite the centre
OF THE SPINE.
139
of the body of each vertebra, than opposite the intervertebral substance. It con-
sists of dense longitudinal fibres, which are intimately adherent to the interverte-
bral substance and prominent margins of the vertebras; but less closely with the
centre of the bodies. In this situation the fibres are exceedingly thick, and serve
to fill up the concavities on their front surface, and to make the anterior surface
of the spine more even. This ligament is composed of several layers of fibres, which
vary in their length, but are closely interlaced with each other. The most super-
99. — Vertical Section of two Vertebrae and their Ligaments,
from the Lumbar Region.
/INTERIOR
COMIViaN
LICT
POSTERIOR
COMMON
tICT
ficial or longest fibres extend between four or five vertebrae. A second subja-
cent set extend between two or three vertebras; whilst a third set, the shortest
and deepest, extend from one vertebra to the next. At the sides of the bodies,
this ligament consists of a few short fibres, which pass from one vertebra to the
next, separated from the median portion by large oval apertures, for the passage
of vessels.
The Posterior Common Ligament is situated within the spinal canal, and
extends along the posterior surface of the bodies of the vertebrae, from the body
of the axis above, where it is continuous with the occipito-axoid ligament, to the
sacrum below. It is broader at the upper than at the lower part of the spine,
and thicker in the dorsal than in the cervic.al or lumbar regions. In the situation
of the intervertebral substance and contiguous margins of the vertebrae, where
the ligament is more intimately adherent, it is broad, and presents a series of
dentations with intervening concave margins; but it is narrow and thick over the
centre of the bodies, from which it is separated by the vencs basis vertebrcB. This
ligament is composed of smooth, shining, longitudinal fibres, denser and more com-
pact than the anterior ligament, and composed of a superficial layer occupying the
interval between three or four vertebrse, and of a deeper layer, which extends
between one vertebra and the next adjacent to it. It is separated from the dura
mater of the spinal cord by some loose filamentous tissue, very liable to serous
infiltration.
The Intervertebral Substance (fig. 99) is a lenticular disc of fibro-cartilage, in-
terposed between the adjacent surfaces of the bodies of the vertebrae, from the axis
to the base of the sacrum. These discs vary in shape, size, and thickness, in
140
ARTICULATIONS.
different parts of the spine. In shape they accurately correspond with the surfaces
of the bodies between which they are placed, being oval in the cervical and lumbar
regions, circular in the dorsal. Their size is greatest in the lumbar region. In
thickness they vary not only in the different regions of the spine, but in different
parts of the same region: thus, they are uniformly thick in the lumbar region;
thickest in front in the cervical and lumbar regions which are convex forwards,
and behind, to a slight extent, in the dorsal region. They thus contribute, in a
great measure, to the curvatures of the spine in the neck and loins; whilst the
concavity of the dorsal region is chiefly due to the shape of the bodies of the
vertebrae. The intervertebral discs form about one-fourth of the spinal column,
exclusive of the first two vertebrae; they are not equally distributed, however,
between the various bones; the dorsal portion of the spine having, in proportion
to its length, a much smaller quantity than in the cervical and lumbar regions,
which necessarily gives to the latter parts greater pliancy and freedom of move-
ment. The intervertebral discs are adherent, by their surfaces, to the adjacent
parts of the bodies of the vertebrae; and by their circumference are closely con-
nected in front to the anterior, and behind to the posterior common ligament;
■whilst in the dorsal region they are connected laterally to the heads of those ribs
which articulate with two vertebrae, by means of the inter-articular ligament;
they consequently form part of the articular cavities in which the heads of these
bones are received.
The intervertebral substance is composed, at its circumference, of laminee of
fibrous tissue and fibro-cartilage; and at its centre of a soft, elastic, pulpy matter.
The laminae are arranged concentrically one within the other, with their edges
turned towards the corresponding surfaces of the vertebrae, and consist of alternate
plates of fibrous tissue and fibro-cartilage. These plates are not quite vertical in
their direction, those near the circumference being curved outwards and closely
approximated; whilst those nearest the centre curve in the opposite direction, and
are somewhat more widely separated. The fibres of which each plate is com-
posed, are directed, for the most part, obliquely from above downwards; the fibres
of an adjacent plate have an exactly opposite arrangement, varying in their direc-
tion in every layer ; whilst in some few they are horizontal. This laminar
arrangement belongs to about the outer half of each disc, the central part being
occupied by a soft, pulpy, highly elastic substance, of a yellowish colour, which
rises up considerably above the surrounding level, when the disc is divided hori-
zontally. This substance presents no concentric arrangement, and consists of
white fibrous tissue, having interspersed cells of variable shape and size. The
pulpy matter is separated from immediate contact with the vertebrae, by the
interposition of thin plates of cartilage.
2. Ligaments connecting- the Lamina.
Ligamenta Subflava.
The Ligamenta Subflava are interposed between the laminse of the vertebrae,
from the axis to the sacrum. They are most distinct when seen from the inner
surface of the spine; when viewed from the outer surface, they appear short,
being overlapped by the laminae. Each ligament consists of two lateral portions,
which commence on each side at the root of either articular process, and pass
backwards to the point where the laminae converge to form the spinous process,
where their margins are thickest, and separated by a slight interval, filled up
with areolar tissue. These ligaments consist of yellow elastic tissue, the fibres of
which, almost perpendicular in direction, are attached to the anterior surface of
the margin of the lamina above, and to the posterior surface, as well as to the
margin of the lamina below. In the cervical region, they are thin in texture,
but very broad and long; they become thicker in the dorsal region; and in the
lumbar acqviire very considerable thickness. Their highly elastic property serves
to preserve the upright posture, and to counteract the efforts of the Flexor muscles
of the spine. These ligaments do not exist between the occiput and atlas, or
between the atlas and axis.
OF THE ATLAS WITH THE AXIS. 141
3. Ligaments connecting the Articular Processes.
Capsular. Synovial Membranes.
The Capsular Ligaments are thin and loose bags of ligamentous fibre attached
to the contiguous margins of the articulating processes of each vertebra, through
the greater part of their circumference, and completed internally by the liga-
menta subflava. They are longer and more loose in the cervical than in the dorsal
or lumbar regions. The capsular ligaments are lined on their inner surface by a
delicate synovial membrane.
4. Ligaments connecting the Spinous Processes.
Inter-spinous. Supra- spinous.
The Inter-spinous Ligaments, thin and membranous, are interposed between the
spinous processes in the dorsal and lumbar regions. Each ligament extends from
the root to near the summit of each spinous process, and connects together their
adjacent margins. They are narrow and elongated in the dorsal region, broader,
quadrilateral in form, and thicker in the lumbar region.
The Supra-spinous Ligament is a strong fibrous cord, which connects together
the apices of the spinous processes from the seventh cervical to the spine of the
sacrum. It is thicker and broader in the lumbar than in the dorsal region, and
intimately blended, in both situations, with the neighbouring aponeuroses. The
most superficial fibres of this ligament connect three or four vertebrae ; those deeper
seated pass between two or three vertebrae; whilst the deepest connect the con-
tiguous extremities of neighbouring vertebrae.
5. Ligaments connecting the Transverse Processes.
Inter-transverse.
The Inter-transverse Ligaments consist of a few thin scattered fibres, interposed
between the transverse processes. They are generally wanting in the cervical
region; in the dorsal, they are rounded cords; in the lumbar region, thin and
membranous.
The two upper vertebrse, the Atlas and Axis, are connected together by liga-
ments distinct from those by which the rest are united.
2. Articulation of the Atlas with the Axis.
The articulation of the anterior arch of the atlas with the odontoid process
forms a lateral ginglymoid joint, whilst that between the articulating processes of the
two bones forms a double arthrodia. The ligaments of this articulation are the
Two Anterior Atlo-Axoid. Transverse.
Posterior Atlo-Axoid. Two Capsular.
Four Synovial Membranes.
Of the Two Anterior Atlo-Axoid Ligaments (fig. 1 00), the most superficial is
a rounded cord, situated in the middle line, attached, above, to the tubercle on the
anterior arch of the atlas ; below, to the base of the odontoid process and body of
the axis. The deeper ligament is a membranous layer, attached, above, to the
lower border of the anterior arch of the atlas ; below, to the base of the odontoid
process and body of the axis. These ligaments are in relation, in front, with the
Recti antici majores.
The Posterior Atlo-Axoid Ligament (fig. lOl) is a broad and thin membranous
layer, attached, above, to the lower border of the posterior arch of the atlas;
below, to the upper edge of the laminae of the axis. This ligament supplies the
place of the ligamenta subflava, and is in relation, behind, with the Inferior oblique
muscles.
142
ARTICULATIONS.
The Transverse Ligament (figs. 102, 103) is a thick and strong ligamentous band,
which arches across the ring of the atlas, and serves to retain the odontoid process
100. — Occipito-Atloid and Atlo-Axoid Ligaments. Front View.
CAPSULAR LIQT b
5YNOVIA1. MEMBRANE
CAPSULAR LICT &
YNOVIAL MEMBRANE
1 01. — Occipito-Atloid and Atlo-Axoid Ligaments. Posterior View.
Arch for passage ofVitft^iralA-fl
in firm connection with its anterior arch. This ligament is flattened from before
backwards, broader and thicker in the middle than at either extremity, and firmly
OF THE ATLAS WITH THE OCCH^ITAL BONE.
143
attached on each side of the atlas to a small tubercle on the inner surface of each
of its lateral masses. As it crosses the odontoid process, a small fasciculus is
derived from its upper and lower borders; the former, passing upwards to be
inserted into the ba- k .■ ^ .■ , , ^.
silar process of the 102.— Articulation between Odontoid Process and Atlas.
occipital bone ; the
latter, downwards, to
be attached to the
root of the odontoid
process: hence this
ligament has received
the name of cruci-
form. The transverse
ligament divides the
ring of the atlas into
two unequal parts:
of these, the poste-
rior and larger serves
for the transmission
of the cord and its membranes; the anterior and smaller serving to retain the
'odontoid process in its position. The lower border of the space formed between
the atlas and transverse ligament being smaller than the upper (on account of the
transverse ligament embracing firmly the narrow neck of the odontoid process),
while the central part of the odontoid process is larger than its base; this process
is still retained in firm connection with the anterior arch when all the other liga-
ments have been divided.
The Capsular Ligaments are two thin and loose capsules, connecting the
articular surfaces of the atlas and axis, the fibres being strongest on the anterior
and external part of the articulation.
There are four Synovial Membranes in this articulation. One lining the
inner surface of each of the capsular ligaments: one between the anterior surface
of the odontoid process and anterior arch of the atlas: and one between the poste-
rior surface of the odontoid process and the transverse ligament. This synovial
membrane often communicates with those between the condyles of the occipital
bone and the articular surfaces of the atlas.
Actions. This joint is capable of great mobility, and allows the rotation of the
atlas, and, with it, of the cranium upon the axis, the extent of rotation being
limited by means of the odontoid ligaments.
Articulation of the Spine with the Cranium.
The ligaments connecting the spine with the cranium may be divided into two
sets: Those connecting the occipital bone with the atlas; Those connecting the
occipital bone with the axis.
3. Articulation of the Atlas with the Occipital Bone.
This articulation is a double arthrodia. Its ligaments are the
Two Anterior Occipito-Atloid,
Posterior Occipito-Atloid.
•Two Lateral Occipito-Atloid.
Two Capsular and Synovial Membranes.
Of the Two Anterior Ligaments (fig. lOO), the most superficial is a strong,
narrow, rounded cord, attached, above, to the basilar process of the occiput; below,
to the tubercle on the anterior arch of the atlas: the deeper ligament is a broad and
thin membranous layer, which passes between the anterior margin of the foramen
magnum above, and the whole length of the upper border of the anterior arch of
the atlas below. This ligament is in relation, in front, with the Eecti antici
minores; behind, with the odontoid ligaments.
144
ARTICULATIONS.
The Posterior Occipito-Atloid Ligament (fig. lOi) is a very broad but thin mem-
branous lamina, intimately blended with the dura mater. It is connected, above, to
the posterior margin of the foramen magnum; below, to the central part of
the upper border of the posterior arch of the atlas. This ligament is incomplete
at each side, and forms, with the superior intervertebral notches, an opening for
the passage of the vertebral artery and sub-occipital nerve. It is in relation, be-
hind, with the Recti postici minores and Obliqui superiores; in front, with the
dura mater of the spinal canal, to which it is intimately adherent.
The Lateral Ligaments are strong bands of fibres, directed obliquely upwards
and inwards, attached, above, to the jugular process of the occipital bone; below,
to the base of the transverse process of the atlas.
The Capsular Ligaments surround the condyles of the occipital bone, and con-
nect them with the articular surfaces of the atlas; they consist of thin and loose
capsules, which enclose the synovial membrane of this articulation. The synovial
membranes between the occipital bone and atlas communicate occasionally with
that between the posterior surface of the odontoid process and transverse liga-
ment.
Actions. The movements permitted in this joint are flexion and extension, '
which give rise to the ordinary forward or backward nodding of the head, besides .
slight lateral motion to one or the other side. When either of these actions is
carried beyond a slight extent, the whole of the cervical portion of the spine assists
in its production.
4. Articulation of the Axis wjth the Occipital Bone.
Occipito-Axoid. Three Odontoid.
To expose these ligaments, the spinal canal should be laid open by removing the
posterior arch of the atlas, the laminae and spinous process of the axis, and that
portion of the occipital bone behind the foramen magnum, as seen in fig. 103.
The Occipito-Axoid Ligament (Apparatus ligamentosus colli) is situated at the
103. — Occipito-Axoid and Atlo-Axoid Ligaments. Posterior View.
tAe Vcrlical jiurfion
^ODONTOID UICT?
OCCIPITOJ CAPSULAR LIC T &
ATLOf CAPSULAR LICT &
Axo I D [ Synovial 'jne/nirane
I
TEMPORO-M AX ILL All Y.
H5
upper part of the front surface of the spinal canal. It is an exceedingly broad and
strong ligamentous band, which covers the odontoid process and its ligaments, and
appears to be a prolongation upwards of the posterior common ligament of the
spine. It is attached, below, to the posterior surface of the body of the axis, and
becoming broader and expanded as it ascends, is inserted into the basilar groove
of the occipital bone, in front of the foramen magnum.
Relations. By its anterior surface, it is intimately connected with the transverse
ligament; by its posterior surface, with the dura mater. By dividing this ligament
transversely across, and turning its ends aside, the transverse and odontoid liga-
ments are exposed.
The Odontoid or Check Ligaments are strong rounded fibrous cords, which
arise one on either side of the apex of the odontoid process, and passing obliquely
upwai'ds and outwards, are inserted into the rough depressions on the inner side
of the condyles of the occipital bone. In the triangular interval left between these
ligaments and the margin of the foramen magnum, a third strong ligamentous band
(ligamentum suspensorium) may be seen, which passes almost perpendicularly from
the apex of the odontoid process to the anterior margin of the foramen, being
intimately blended with the anterior occipito-atloid ligament.
Actions. The odontoid ligaments serve to limit the extent to which rotation
of the cranium may be carried; hence they have received the name of check
ligaments.
5. TeMPORO-M AXILLARY ARTICULATION.
This articulation is a double arthrodia. The parts entering into its formation
are, on each side, the anterior part of the glenoid cavity of the temporal bone and
the eminentia articularis above; with the condyle of the lower jaw below. The
ligaments are the following.
External Lateral. Capsular.
Internal Lateral. Inter-articular Fibro- cartilage.
Stylo-maxillary, Two Synovial Membranes.
104, — Temporo-Maxillary Articulation. External View.
146
ARTICULATIONS.
105. — Temporo-Maxillary Articulation. Internal View,
The External Lateral Ligament (fig, 1 04) is a short, thin, and narrow fasciculus,
attached above to the outer surface of the zygoma and to the rough tubercle on its
lower border; below, to the outer surface and posterior border of the neck of the
lower jaw. This ligament is a little broader above than below; its fibres are
placed parallel with one another, and directed obliquely downwards and backwards.
Externally, it is covered by the parotid gland and by the integument. Internally,
it is in relation with the inter-articular fibro-cartilage and the synovial
membranes.
The Internal Lateral lAgament (fig. 105) is a long, thin, and loose band,
attached above by its narrow extremity to the spinous process of the sphenoid
bone, and becoming
broader as it descends,
is inserted into the inner
margin of the dental
foramen. Its outer sur-
face is in relation above
with the External ptery-
goid muscle; lower down
it is separated from the
neck of the condyle by
the internal maxillary
artery; and still more
inferiorly the inferior
dental vessels and nerve
separate it from the ra-
mus of the jaw. Inter-
nally it is in relation
with the Internal ptery-
goid.
The Stylo-maxillary
Ligament is a thin apo-
neurotic cord, which
extends from near the
apex of the styloid pro-
cess of the temporal bone, to the angle and posterior border of the ramus of the
lower jaw, between the Masseter and Internal pterygoid muscles. This ligament
separates the parotid from the sub-maxillary gland, and has attached to its inner
side part of the fibres of origin of the Stylo-glossus muscle. Although usually
classed among the ligaments of the jaw, it can only be considered as an accessory
in the articulation.
The Capsular Ligament consists of a thin and loose ligamentous capsule,
attached above to the circumference of the glenoid cavity and the articular surface
immediately in front; below, to the neck of the condyle of the lower jaw. It
consists of a few thin scattered fibres, and can hardly be considered as a distinct
ligament; it is thickest at the back part of the articulation.
The Inter-articular Fibro-cartilage (fig. 106) is a thin plate of a transversely
oval form, placed horizontally between the condyle of the jaw and the glenoid
cavity. Its upper surface is concave from before backwards, and a little convex
transversely, to accommodate itself to the form of the glenoid cavity. Its under
surface, where it is in contact with the condyle, is concave. Its circumference is
connected externally to the external lateral ligament; internally, to the capsular
ligament; and in front to the tendon of the External pterygoid muscle. It is
thicker at its circumference, especially behind, than at its centre, where it is some-
times perforated. The fibres of which it is composed have a concentric arrange-
ment, more apparent at the circumference than at the centre. Its surfaces are
smooth, and divide the joint into two cavities, each of which is furnished with
CO STO- VERTEBRAL.
f47
.-.^.jaj'^
a separate synovial membrane. When the fibro-cartilage is perforated, the syno-
vial membranes are continuous with one another.
The Synovial Mem- _ . , ^
branes, two in number, '^^.-Vertical Section of Temporo-MaxiUary Articulation.
are placed one above,
and the other below the
fibro-cartilage. The
upper one, the larger
and looser of the two,
after lining the cartilage
covering the glenoid
cavity and eminentia
articulai'is, is continued
over the upper surface
of the fibro-cartilage.
The lower one is inter-
posed between the un-
der surface of the fibro-cartilage and the condyle of the jaw, being prolonged
downwards a little further behind than in front.
Actions. The movements permitted in this articulation are very extensive. Thus
the jaw may be depressed or elevated, or it may be carried forwards or backwards, or
from side to side. It is by the alternation of these movements performed in suc-
cession, that a kind of rotatory movement of the lower jaw upon the upper takes
place, which materially assists in the mastication of the food.
If the movement of depression is carried only to a slight extent, the condyles
remain in the glenoid cavities, their anterior part descending only to a slight extent,
but if depression is considerable, the condyles glide from the glenoid fossge on to
the eminentia articularis, carrying with them the inter-articular fibro-cartilages.
When the jaw is elevated, the condyles and fibro-cartilages are carried backwards
into their original position. When the jaw is carried forwards or backwards, a
horizontal gliding movement of the fibro-cartilages and condyles upon the glenoid
cavities takes place in the antero-posterior direction ; whilst in the movement from
side to side, this occurs in the lateral direction.
6. Articulation of the Ribs with the Vertebra.
The articulation of the ribs with the vertebral column, may be divided into two
sets. I. Those which connect the heads of the ribs with the bodies of the vertebrae
2. Those which connect the neck and tubercle of the ribs with the transverse
processes.
I. Articulation between the Heads of the Ribs and the Bodies of
THE Vertebra.
These form a series of angular ginglymoid joints, connected together by the
following ligaments: —
Anterior Costo-vertebral or Stellate.
Capsular.
Inter-articular.
Two Synovial Membranes.
The Anterior Costo-vertebral or Stellate Ligament (fig. 107) connects the ante-
rior part of the head of each rib, with the sides of the bodies of the vertebras, and
the intervening intervertebral disc. It consists of three flat bundles of liga-
mentous fibres, which radiate from the anterior part of the head of the rib. The
superior fasciculus passes upwards to be connected with the body of the vertebra
above; the inferior one descends to the body of the vertebra below; and the mid-
dle one, the smallest and least distinct, passes horizontally inwards to be attached
to the intervertebral substance.
L 2
148
ARTICULATIONS.
Relations. In front with the thoracic ganglia of the sympathetic, the pleura,
and on the right side, the vena azygos major; behind, with the inter-articular liga-
ment and synovial membranes.
In the first rib, which articulates with a single vertebra only, this ligament
does not present a dis-
tinct division into three
107. — Costo-vertebral and Costo-transverse Ariculations.
Anterior View.
fasciculi ; its superior
fibres, however pass to
be attached to the body
of the last cervical ver-
tebra, as well as to that
of the vertebra with
which the rib articu-
lates. In the eleventh
and twelfth ribs, which
also articulate with a
single vertebra, the
same division does not
exist, but the superior
fibres of the ligament,
in each case, are con-
nected with the verte-
bra above, as well as
that with which the ribs
articulate.
The Capsular Liga-
ment is a thin and
loose ligamentous bag,
which surrounds the
joint between the head of the rib and the articular cavity formed by the junction
of the vertebra3. It is very thin, firmly connected with the anterior ligament, and
most distinct at the upper and lower parts of the articulation.
The Inter -articular Ligament is situated in the interior of the articulation. It
consists of a short band of fibres, flattened from above downwards, attached by one
extremity to the sharp crest on the head of the rib, and by the other to the inter-
vertebral disc. It divides the joint into two cavities, which have no communica-
tion with one another, and are each lined by a separate synovial membrane.
In the first, eleventh, and twelfth ribs, the inter-articular ligament does not exist,
consequently there is but one synovial membrane.
Actions. The movements permitted in these articulations are limited to elevation,
depression, and slightly forwards and backwards. This movement varies however,
very much in its extent in different ribs. The first rib is almost entirely immov-
able, excepting in strong and violent inspirations. The movement of the second
rib is also not very extensive. In the other ribs, their mobility increases succes-
sively to the two last, which are very moveable. The ribs are generally more
moveable in the female than in the male.
2. Articulation between the Neck and Tubercle of the Ribs with
THE Transverse Processes.
The ligaments connecting these parts are —
Anterior Costo-Transverse.
Middle Costo-Transverse (Interosseous).
Posterior Costo-Transverse.
Capsular and Synovial Membrane.
The Ante7'ior Costo-Transverse Ligament (fig. 108.) is a bi'oad and strong
COSTO-TRANSVERSE.
149
band of fibres, attached below to the sharp crest on the upper border of the neck
of each rib, and passing obliquely upwards and outwards, to the lower border of
the transverse process immediately above. It is broader below than above,
broader and thinner between the lower ribs than between the upper, and more
distinct in front than behind. This ligament is in relation, in front, with the
intercostal vessels and nerves; behind, with the Longissimus dorsi. Its internal
io3. — Costo-Trausverse Articulation. Seen from above.
ANTERIOR COSTO-TRANSVERSE LIG-r DIVID
MIDDLE COSTO-TRANSVERSE 0»*,
INTEROSSEOUS
POSTERIOR COSTO-TRANSVERSE LIG'^
CAPSULAR MEMBRANE
border completes an aperture formed between it and the articular processes,
through which pass the posterior branches of the intercostal vessels and nerve.
Its external border is continuous with a thin aponeurosis, which covers the
External intercostal muscle.
The^r^^ and last ribs have no anterior costo-transverse ligament.
The Middle Costo- Transverse or Interosseous Ligament consists of short, but
sti'ong, fibres, which pass between the rough surface on the posterior part of the
neck of each rib, and the anterior surface of the adjacent transverse process. In
order fully to expose this ligament, a horizontal section should be made across the
transverse process and corresponding part of the rib; or the rib may be forcibly
separated from the transverse process, and its fibres torn asunder.
In the eleventh and tioelfth ribs, this ligament is quite rudimentary.
The Posterior Costo-Transverse Ligament is a short, but thick and strong,
fasciculus, which passes obliquely from the summit of the transverse process to
the rough non-articular portion of the tubercle of the rib. This ligament is
shorter and more oblique in the upper, than in the lower ribs. Those correspond-
ing to the superior ribs ascend, and those of the inferior ones slightly descend.
In the eleventh and twelfth ribs, this ligament is wanting.
The articular portion of the tubercle of the rib, and adjacent transverse process,
form an arthrodial joint, provided with a thin capsular ligament attached to
the circumference of the articulating surfaces, and enclosing a small synovial
membrane.
In the eleventh and twelfth ribs, this articulation is wr.nting.
Actions. The movement permitted in these joints, is limited to a slight gliding
motion of the articular surfaces one upon the other.
150
ARTICULATIONS.
7. Articulation of the Cartilages of the Ribs with the Sternum.
The articulation of the cartilages of the true ribs with the sternum are arthro-
dial joints. The ligaments connecting them are —
Anterior Costo- Sternal.
Posterior Costo- Sternal.
Capsular.
Synovial Membranes.
The Anterior Costo- Sternal Ligament (fig. 109) is a broad and thin membranous
109. — Costo-Sternal, Costo-Xiphoid, and Inter-costal Articulations. Anterior View.
17ic synovial cavities exposed
by a verttjcaL seetioti ffftjic SteviMin k Cki
coii/tuiuLoiu! vdth tStcrTbuvi
INTER-ARTICULAR llc!
two SiiTiovbal, 7ne7niraTte9
Single S/ytunM
MenAmnOM
band that radiates from the inner extremity of the cartilages of the true ribs, to the
anterior surface of the sternum. It is composed of fasciculi, which pass in differ-
1
COSTO-STERNAL, COSTO-XIPIIOID, AND INTER-COSTAL. 151
ent directions. The superior fasciculi ascend obliquely, the inferior pass obliquely
downwards, and the middle fasciculi horizontally. The superficial fibres of this
ligament are the longest; they intermingle with the fibres of the ligaments above
and beneath them, with those of the opposite side, and with the tendinous fibres
of origin of the Pectoralis major; forming a thick fibrous membrane, which covers
the surface of the sternum, but is more distinct at the lower than at the upper
part.
The Posterior Costo- Sternal Ligament, less thick and distinct than the ante-
rior, is composed of fibres which radiate from the posterior surface of the sternal
end of the cartilages of the true ribs, to the posterior surface of the sternum,
becoming blended with the periosteum.
The Capsular Ligament surrounds the joints formed between the cartilages of
the true ribs and the sternum. It is very thin, intimately blended with the
anterior and posterior ligaments, and strengthened at the upper and lower part of
the articulation by a few fibres, which pass from the cartilage to the side of the
sternum. These ligaments protect the synovial membranes.
Synovial Membranes. The cartilage of the first rib is directly continuous with
the sternum, the synovial membrane being absent. The cartilage of the second
rib articulates with the sternum by means of an inter-articular ligament, attached
by one extremity to the ridge which separates the two articular facets of the
cartilage of the second rib, and by the other extremity to the cartilage which
unites the first and second pieces of the sternum. This articulation is provided
with two synovial membranes. That of the third rib has also two synovial mem-
branes; and that of the fourth, fifth, sixth, and seventh, each a single synovial
membrane. These synovial membranes may be demonstrated by removing a thin
section from the anterior surface of the sternum and cartilages, as seen in the
figure. After middle life, the articular surfaces lose their polish, become rough-
ened, and the synovial membranes appear to be wanting. In old age, the articu-
lations do not exist, the cartilages of most of the ribs becoming firmly united to
the sternum. The cartilage of the seventh rib, and occasionally also that of the
sixth, is connected to the anterior surface of the ensiform appendix, by a band of
ligamentous fibres, which varies in length and breadth in different subjects. It is
called the costo-xiphoid ligament.
Actions. The movements which are permitted in the costo-sternal articulations,
are limited to elevation and dej)ression; and these only to a slight extent.
Articulation of the Cartilages of the Ribs with each other.
The cartilages of the sixth, seventh, and eighth ribs articulate, by their lower
borders, with the corresponding margin of the adjoining cartilages, by means of a
small, smdoth, oblong-shaped facet. Each articulation has a perfect synovial
membrane enclosed in a thin capsular ligament, strengthened externally and
internally by some ligamentous fibres (intercostal ligaments), which pass from one
cartilage to the other, and which are intimately united to the perichondrium.
Sometimes the cartilage of the fifth rib, more rarely that of the ninth, articulate,
by their lower borders, with the corresponding cartilages by small oval facets;
more frequently they are connected together by a few ligamentous fibres. Occa-
sionally, the articular surfaces above mentioned are found wanting.
Articulation of the Ribs with their Cartilages.
The outer extremity of each costal cartilage is received into a depression in
the sternal end of the ribs, and held together by the periosteum.
8. Ligaments of the Sternum.
The first and second pieces of the Sternum are united by a layer of cartilage
which rarely ossifies, except at an advanced period' of life. These two segments
are connected by an anterior and posterior ligament.
152
ARTICULATIONS.
The anterior sternal ligament consists of a layer of fibres, having a longi-
tudinal direction; they blend with the fibres of the anterior costo-sternal liga-
ments on both sides, and with the aponeurosis of origin of the Pectoralis major.
This ligament is rough, irregular, and much thicker at the lower than at the
upper part of this bone.
The posterior sternal ligament is disposed in a somewhat similar manner on
the posterior surface of the articulation.
9. Articulation of the Pelvis with the Spine.
The ligaments connecting the last lumbar vertebra with the sacrum are similar
to those which connect the segments of the spine with each other, viz. I. The con-
tinuation downwards of the anterior and posterior' common ligaments. 2. The
inter-vertebral substance connecting the flattened oval surfaces of the two bones,
thus forming an amphiarthrodial joint. 3. Ligamenta subflava, connecting the
arch of the last lumbar vertebra with the posterior border of the sacral canal.
4. Capsular ligaments and synovial membranes connecting the articulating pro-
cesses and forming a double arthrodia. 5. Inter- and supra-spinous ligaments. '
The two proper ligaments connecting the pelvis with the spine are the lumbo-
sacral amd lumbo-iliac.
1 10. — Articulatious of Pelvis and Hip. Anterior View.
ofeoTm
<>J PSOAS m ILIACU5
The Lumbosacral Ligament (fig. no) is a short, thick, triangular fasciculus,
connected above to the lower and front part of the transverse process of the last
lumbar vertebra, and passing obliquely outwards, is attached below to the lateral
surface of the base of the sacrum; becoming blended with the anterior sacro-iliac
ligament. This ligament is in relation anteriorly with the Psoas muscle.
The Lumbo-iliac Ligament (fig. no) passes horizontally outwards from the
SACRO-ILIAC.
153
apex of the transverse process of the last lumbar vertebra, to that portion of the
crest of the ilium immediately in front of the sacro-iliac articulation. It is of a
triangular form, thick and narrow internally, broad and thinner externally; and is
in relation, in front, with the Psoas muscle; behind, with the muscles occupying
the vertebral groove; above, with the Quadratus lumborum.
10. Articulations of the Pelvis.
The Ligaments connecting the bones of the pelvis with each other may be
divided into four groups, i. Those connecting the sacrum and ilium. 2. Those
passing between the sacrum and ischium. 3. Those connecting the sacrum and
coccyx. 4. Those between the two pubic bones.
I. Articulation of the Sacrum and Ilium.
The sacro-iliac articulation is an amphiarthrodial joint, formed between the
lateral surfaces of the sacrum and ilium. The anterior or auricular portion of the
articular surfaces is covered with a thin plate of cartilage, thicker on the sacrum
than on the ilium. The surfaces of these cartilages in the adult are rough and
irregular, and separated from one another by a soft yellow pulpy substance. At
an early period of life, occasionally in the adult, and in the female during preg-
1 1 1. — Articulations of Pelvis and Hip. Posterior View.
: on LESSER
SACRO-SCiATIC L I aT .
nancy, 'they are smooth and lined by a delicate synovial membrane. The ligaments
connecting these surfaces are the anterior and posterior sacro-iliac.
The Anterior Sacro-iliac Ligament consists of numerous thin ligamentous bands,
which connect the anterior surfaces of the sacrum and ilium.
The Posterior Sacro-iliac (fig. Ill) is a strong interosseous ligament, situated
in the deep depression between the sacrum and ilium behind, and forming the
154 ARTICULATIONS.
chief bond of connexion between these bones. It consists of numerous strong
fasciculi, which pass between the bones in various directions. Three of these are
of large size; the two superior, nearly horizontal in direction, arise from the first
and second transverse tubercles on the posterior surface of the sacrum, and are
inserted into the rough uneven surface at the posterior part of the inner surface
of the ilium. The third fasciculus, oblique in direction, is attached by one extre-
mity to the third or fourth transverse tubercle on the posterior surface of the
sacrum, and by the other to the posterior superior spine of the ilium; it is some-
times called the oblique sacro-iliac ligament.
2. Akticulation op the Sacrum and Ischium.
The Great Sacro- Sciatic (Posterior).
The Lesser Sacro- Sciatic (Anterior).
The Great or Posterior Sacro- Sciatic Ligament is situated at the posterior
and inferior part of the pelvis. It is thin, flat, and triangular in form; narrower
in the middle than at the extremities; attached by its broad base to the posterior
inferior spine of the ilium, to the third and fourth transverse tubercles on the
sacrum, and to the lower part of the lateral margin of that bone and the coccyx;
passing obliquely downwards, outwards, and forwards, it becomes narrow and
thick; and at its insertion into the inner margin of the tuberosity, it increases in
breadth, and is prolonged forwards along the inner margin of the ramus forming
the falciform ligament. The free concave edge of this ligament has attached to
it the obturator fascia, with which it forms a kind of groove, protecting the
internal pudic vessels and nerve. One of its surfaces is turned towards the peri-
naeum, the other towards the Obturator internus muscle.
The posterior surface of this ligament gives origin, by its whole extent, to
fibres of the Gluteus maximus. Its anterior surface is united to the lesser sacro-
sciatic ligament. Its superior border forms the lower boundary of the lesser
sacro-sciatic foramen. Its loioer border forms part of the boundary of the peri-
neum. This ligament is pierced by the coccygeal branch of the sciatic artery.
The Lesser or Anterior Sacro- Sciatic Ligament, much shorter and smaller
than the preceding, is thin, triangular in form, attached by its apex to the spine
of the ischium, and internally, by its broad base, to the lateral margins of the
sacrum and coccyx, anterior to the attachment of the great sacro-sciatic ligament,
with which its fibres are intermingled.
It is in relation, anteriorly, with the Coccygeus muscle; posteriorly, it is
covered by the posterior ligament, and crossed by the pudic vessels and nerves.
Its superior border forms the lower boundary of the great sacro-sciatic foramen.
Its inferior border, part of the lesser sacro-sciatic foramen.
These two ligaments convert the sacro-sciatic notches into foramina. The
superior or larger sacro-sciatic foramen is bounded, in front and above, by the
posterior border of the os innominatum; behind, by the great sacro-sciatic liga-
ment; and below, by the lesser ligament. It is partially filled up, in the recent
state, by the Pyriformis muscle. Above this muscle, the gluteal vessels and
nerve emerge from the pelvis; and below it; the ischiatic vessels and nerves, the
internal pudic vessels and nerve, and the nerve to the Obturator internus. The
inferior or smaller sacro-sciatic foramen is bounded, in front, by the tuber ischii ;
above, by the spine and lesser ligament; behind, by the greater ligament. It
transmits the tendon of the Obturator internus muscle, its nerve, and the pudic
vessels and nerve.
3. Articulation of the Sacrum and Coccyx.
This articulation is an amphiarthrodial joint, formed between the oval surface
on the summit of the sacrum, and the base of the coccyx. It is analogous to the
SACRO-COCCYGEAL. 155
joints between the bodies of the vertebrae, and is connected by similar ligaments.
They are the
Anterior Sacro- Coccygeal.
Posterior Sacro-Coccygeal.
Inter-articular Fibro-Cartilage.
The Anterior Sacro-Coccygeal Ligament consists of a few irregular fibres,
which descend from the anterior surface of the sacrum to the front of the coccyx,
becoming blended with the periosteum.
The Posterior Sacro-Coccygeal Ligament is a flat band of ligamentous fibres,
of a pearly tint, which arises from the margin of the lower orifice of the sacral
canal, and descends to be inserted into the posterior surface of the coccyx. This
ligament completes the lower and back part of the sacral canal. Its superficial fibres
are much longer than the deep-seated; the latter extend from the apex of the sacrum
to the upper cornua of the coccyx. Anteriorly, it is in relation with the arach-
noid membrane of the sacral canal, a portion of the sacrum, and almost the whole
of the posterior surface of the coccyx; posteriorly, with some aponeurotic fibres
from the Gluteus maximus.
An Inter-articular Fibro-Cartilage is interposed between the contiguous sur-
faces of the sacrum and coccyx ; it differs from that interposed between the bodies
of the vertebrae, in being thinner, and its central part more firm in texture. It is
somewhat thicker in front and behind, than at the sides. Occasionally a synovial
membrane is found where the coccyx is freely movable, which is more especially
the case during pregnancy.
The different segments of the coccyx are connected together by an extension
downwards of the anterior and posterior sacro-coccygeal ligaments, a thin annular
disc of fibro-cartilage being interposed between each of the bones. In the adult
male, all the pieces become ossified; but in the female, this does not commonly
occur until a later period of life. The separate segments of the coccyx are first
united, and at a more advanced age the joint between the sacrum and the
coccyx.
Actions. The movements which take place between the sacrum and coccyx,
and between the different pieces of the latter bone, are slightly forwards and back-
wards; they are very limited. Their mobility increases during pregnancy.
4. Articulation of the Pubes.
The articulation between the ossa pubis is an amphiarthrodial joint, formed by
the junction of the two oval surfaces which have received the name of the sym-
physis. The ligaments of this articulation are the
Anterior Pubic. Posterior Pubic.
Superior Pubic. Sub-Pubic.
Inter-articular Fibro-Cartilage.
The Anterior Pubic Ligament consists of several superimposed layers, which
pass across the anterior surface of the articulation. The superficial fibres pass
obliquely from one bone to the other, decussating and forming an interlacement
with the fibres of the aponeurosis of the External oblique muscle. The deep
fibres pass transversely across the symphysis, and are blended with the inter-
articular fibro-cartilage.
The Posterior Pubic Ligament consists of a few thin, scattered fibres, which
unite the two pubic bones posteriorly.
The Superior Pubic Ligament is a band of fibres, which connects together the
two pubic bones superiorly.
The Sub-Pubic Ligament is a thick, triangular arch of ligamentous fibres, con-
necting together the two pubic bones below, and forming the upper boundary of
the pubic arch. Above, it is blended with the • inter-articular fibro-cartilage;
laterally, with the rami of the pubes. Its fibres are of a yellowish colour, closely
connected, and have an arched direction.
156
ARTICULATIONS.
The Inter-articular Fibro- Cartilage consists of two oval-shaped plates, one
covering the surface of each symphysis pubis. They vary in thickness in
different subjects, and project somewhat beyond the level of the bones, espe-
cially behind. The outer surface of each is firmly connected to the bone by a
series of nipple-like processes, which accurately fit within corresponding depres-
sions on the osseous surface. Their opposed surfaces are connected, in the greater
part of their extent, by an intermediate fibrous elastic-tissue; and by their cir-
cumference to the various ligaments surrounding the joint. An interspace is left
between the two plates at the upper and back part of the articulation, where the
1 1 2. — Vertical Section of the Symphysis Pubis.
Made near its Posterior Surface.
Xii/o Fthiro-Ca/rtiiacjinoas jplntes
Xnte/rmcdiate
Sytimfuil cavity
fibrous-tissue is deficient, and the surface of the fibro-cartilage lined by epithelium.
This space is found at all periods of life, both in the male and female; but it is
larger in the latter, especially during pregnancy, and after parturition. It is
most frequently limited to the upper and back part of the joint; but it occasion-
ally reaches to the front, and may extend the entire length of the cartilages.
This structure may be easily demonstrated, by making a vertical section of the
symphysis pubis near its posterior surface.
The Obturator Ligament is a dense membranous layer, consisting of fibres
which interlace in various directions. It is attached to the circumference of the
obturator foramen, which it closes completely, except at its upper and outer part,
where a small oval canal is left for the passage of the obturator vessels and nerve.
It is in relation, in front, with the Obturator externus ; behind, with the Obtura-
tor internus; both of which muscles are in part attached to it.
ARTICULATIONS OF THE UPPER EXTREMITY.
The articulations of the Upper Extremity may be arranged into the following
groups: — I. Sterno-clavicular articulation. 2. Scapulo-clavicular articulation.
3. Ligaments of the Scapula. 4. Shoulder-joint. 5. Elbow-joint. 6. Radio-
ulnar articulation, 7. Wrist-joint. 8. Articulation of the Carpal bones. 9.
Carpo-metacarpal articulation. 10. Metacarpo-phalangeal articulation. 1 1. Arti-
culation of the Phalanges.
I. Sterno-Clavicular Articulation.
The Sterno-Clavicular is an arthrodial joint. The parts entering into its
formation are the sternal end of the clavicle, the upper and lateral part of the
STERNO-CLAVICULAR.
157
first piece of the sternum, and tile cartilage of the first rib. The articular surface
of the clavicle is much longer than that of the sternum, and invested with a
113. — Sterno-CIavicular Articulation. Anterior View.
layer of cartilage, which is considerably thicker than that on the latter bone.
The ligaments of this joint are the
Anterior Sterno-CIavicular.
Posterior Sterno-CIavicular.
Inter- Clavicular.
Costo-Clavicular (rhomboid).
Inter- Articular Fibro-Cartilage.
Two Synovial Membranes.
The Anterior Sterno-CIavicular Ligament is a broad band of ligamentous
fibres, which covers the anterior surface of the articulation, being attached, above,
to the upper and front part of the inner extremity of the clavicle; and, passing
obliquely downwards and inwards, is attached, below, to the front and upper part
of the first piece of the sternum. This ligament is covered anteriorly by the
sternal portion of the Sterno-cleido-mastoid and the integument; behind, it is in
relation with the inter-articular fibro-cartilage and the two synovial membranes.
The Posterior Sterno-CIavicular Ligament is a broad band of fibres, which
covers the posterior surface of the articulation, being attached, above, to the pos-
terior part of the inner extremity of the clavicle; and, passing obliquely down-
wards and inwards, to be connected, below, to the posterior and upper part of the
sternum. It is in relation, in front, with the inter-articular fibro-cartilage and
synovial membranes; behind, with the Sterno-hyoid and Sterno-thyroid muscles.
The Inter- Clavicular Ligament is a flattened ligamentous band, which varies
considerably in form and size in different individuals; it passes from the superior
part of the inner extremity of one clavicle to the other, and is closely attached to
the upper margin of the sternum. It is in relation, in front, with the integu-
ment; behind, with the Sterno-thyroid muscles.
The Costo-Clavicular Ligament {rhomboid^ is a short, flat, and strong band of
ligamentous fibres of a rhomboid form, attached, below, to the upper and inner
part of the cartilage of the first rib; and, ascending obliquely backwards and out-
wards,' to be attached, above, to the rhomboid depression on the under surface
of the inner extremity of the clavicle. It is in relation, in front, with the tendon
of origin of the Subclavius; behind, with the subclavian vein.
The Inter- articular Fibro-Cartilage is a flat and nearly circular disc, inter-
posed between the articulating surfaces of the sternum and clavicle. It is attached
above, to the upper and posterior border of the clavicle; below, to the cartilage of
158 AETICULATIONS.
the first rib, at its junction with the sternum; and by its circumference to the
anterior and posterior sterno-clavicular ligaments. It is thicker at the circum-
ference, especially its upper and back pai't, than at its centre, or below. It
divides the joint into two cavities, each of which is furnished with a separate
synovial membrane; when the fibro-cartilage is perforated, which not unfrequently
occurs, the synovial membranes communicate.
Of the two Synovial Membranes found in this articulation, one is reflected over
the sternal end of the clavicle, the adjacent surface of the fibro-cartilage, and
cartilage of the first rib; the other is placed between the articular surface of the
sternum and adjacent surface of the fibro-cartilage; the latter is the more loose of
the two. TJtiey seldom contain much synovia.
Actions. This articulation is the centre of the movements of the shoulder, and
admits of motion in nearly every direction — upwards, downwards, backwards,
forwards, as well as circumduction; the sternal end of the clavicle and the inter-
articular cartilage gliding on the articular surface of the sternum.
2. ScAPULO- Clavicular Articulation.
The Scapulo- Clavicular is an arthrodial joint, formed between the outer
extremity of the clavicle, and the upper edge of the acromian process of the
scapula. Its ligaments are the
Superior Acromio-Clavicular.
Inferior Acromio-Clavicular,
{Trapezoid
and
Conoid.
Inter-articular Fibro-Cartilage.
Two Synovial Membranes.
The Superior Acromio-Clavicular Ligament is a broad band of fibres, of a
quadrilateral form, which covers the superior part of the articulation, extending
between the upper part of the outer end of the clavicle, and the superior part of
the acromion. It is composed of parallel fibres, which interlace, above, with the
aponeurosis of the Trapezius and Deltoid muscles; below, it is in contact with the
inter-articular fibro-cartilage and synovial membranes.
The Inferior Acromio-Clavicular Ligament, somewhat thinner than the pre-
ceding, covers the inferior part of the articulation, and is attached to the adjoining
surfaces of the two bones. It is in relation, above, with the inter-articular fibro-
cartilage (when it exists) and the synovial membranes; below, with the tendon of
the Supra- spinatus. These two ligaments are continuous with each other in front
and behind, and form a complete capsule around the joint.
The Coraco- Clavicular Ligament serves to connect the clavicle with the
coracoid process of the scapula. It consists of two distinct fasciculi, which have
received separate names.
The Trapezoid Ligament, the anterior and external fasciculus, is a broad, thin,
quadrilateral-shaped band of fibres, placed obliquely between the acromian process
and the clavicle. It is attached, below, to a rough line at the inner and back
part of the upper surface of the coracoid process; above, to the oblique line on
the under surface of the clavicle. Its anterior border is free; its posterior is
joined with the conoid ligament, forming by their junction a projecting angle.
The Conoid lAgament, the posterior and internal fasciculus, is a dense band of
fibres, conical in form, the base being turned upwards, the summit downwards.
It is attached by its apex to a rough depression at the anterior and inner side of
the base of the coracoid process, internal to the preceding; above, by its expanded
base, to the rough tubercle on the under surface of the clavicle. These ligaments
are in relation, in front, with the Subclavius; behind, with the Trapezius: they
serve to limit rotation of the scapula forwards and backwards.
PROPER LIGAMENTS OF SCAPULA.
159
The Inter- articular Fibro- Cartilage is most frequently absent in this articula-
tion. When it exists, it generally only partially separates the articular surftxces,
and occupies the upper part of the articulation. More rarely, it completely sepa-
rates this joint into two cavities.
114. — The Left Shoulder- Joint, Scapulo-Clavicular Articulations,
and Proper Ligaments of Scapula.
There are tico Synovial Membranes where a complete inter-articular cartilage
exists; more frequently there is only one synovial membrane.
Actions. The movements of this articulation are of two kinds. I. A gliding
motion of the articular end of the clavicle on the acromion. 2. Rotation of the
scapula forwards and backwards upon the clavicle, the extent of this rotation being
limited by the two portions of the coraco-clavicular ligament.
3. Proper Ligaments of the Scapula.
The proper ligaments of the scapula are the
Coraco-acromial. Transverse (Coracoid).
The Coraco-acromial Ligament is a broad, thin, and flat band, of a triangular
shape, extended transversely across the upper part of the shoulder-joint, between
the coracoid process and the acromion. It is attached by its apex to the summit
of the acromion just in front of the articular surface for the clavicle, and by its
broad base to the whole length of the outer border of the coracoid process. Its
posterior fibres are directed obliquely backwards and outwards, its anterior fibres
transversely. This ligament completes the vault formed by the acromion and cora-
coid processes for the protection of the head of the humerus. It is in relation,
above, with the clavicle and under surface of the deltoid ; below, with the tendon of
i6o ARTICULATIONS.
the Supra- spinatus itmscle, a bursa being interposed. Its anterior border is con-
tinuous with a dense cellular lamina that passes beneath the deltoid upon the
tendons of the Supra- and Infra-spinati muscles.
The Transverse or Coracoid Ligament, is a thin and flat fasciculus, narrower
at the middle than at the extremities, attached by one end to the base of the cora-
coid process, and by the other, to the inner extremity of the scapular notch, which
it converts into a foramen. The supra- scapular nerve passes through this foramen,
its accompanying vessels above it.
4. Shoulder Joint.
The Shoulder is an enarthrodial or ball and socket joint. The bones en-
tering into its formation are the large globular head of the humerus, which is
received into the shallow glenoid cavity of the scapula, an arrangement which
permits of very considerable movement, whilst the joint itself is protected against
displacement by the strong ligaments and tendons which surround it, and above by
an arched vault, formed by the under surface of the coracoid and acromion processes,
and the coraco-aci'omion ligament. The two articular surfaces are covered by a
layer of cartilage, which on the head of the humerus is thicker at the centre than
at the circumference, the reverse being observed in the glenoid cavity. Its liga-
ments are the
Capsular. Glenoid.
Coraco-humeral. Synovial Membrane.
The Capsular Ligament completely encircles this articulation; being attached,
above, to the circumference of the glenoid cavity beyond the glenoid ligament; below,
to the margin of the neck of the humerus, approaching nearer to the articular carti-
lage above, than in the rest of its extent. It is thicker above than below, remark-
ably loose and lax, and much larger and longer than is necessary to keep the bones
in contact, allowing them to be separated from each other more than an inch, an
evident provision for that extreme freedom of movement which is peculiar to
this articulation. Its external surface is strengthened above by the Supra spi-
natus; above and internally by the coraco-humeral ligament; below, where it is
thin and weak, the long tendon of the Triceps is separated from it by a little loose
areolar tissue; externally the tendons of the Infra- spinatus and Teres minor are
firmly attached to it; and internally, the tendon of the Sub-scapularis. The cap-
sular ligament usually presents three openings; one at its inner side, partially
filled up by the tendon of the Sub-scapularis; it establishes a communication be-
tween the synovial membrane of the joint, and a bursa beneath the tendon of that
muscle; a second, not constant, at its external part, where a communication
exists between the joint and a bursal sac belonging to the Infra- spinatus muscle.
The third is seen in the lower border of the ligament, between the two tuberosities,
for the passage of the tendon of the Biceps muscle.
The Coraco-humeral or Accessory Ligament, is a broad band which strengthens
the upper and inner part of the capsular ligament. It arises from the outer border
of the coracoid process, and descends obliquely downwards and outwards to the
anterior part of the great tuberosity of the humerus, being blended with the tendon
of the Supra-spinatus muscle. This ligament is intimately united to the capsular
in the greater part of its extent.
The Glenoid Ligament is a fibro-cartilaginous band attached around the margin
of the glenoid cavity. It is triangular on section, the thickest portion being fixed to
the circumference of the cavity, the free edge being thin and sharp. It appears
to be mainly formed of the fibres of tlae long tendon of the Biceps muscle, bifur-
cating at the upper part of the glenoid cavity into two fasciculi, which encircle
its margin and unite at its lower part. This ligament deepens the cavity for articu-
lation, and protects the edges ofthe bone. It is lined by the synovial membrane.
The Synovial Membrane lines the glenoid cavity and the fibro-cartilaginous rim
I
ELBOW JOINT.
i6i
surrounding it; it is then reflected over the internal surface of the capsular liga-
ment, lines the lower part and sides of the neck of the humerus, and is con-
tinued over the cartilage covering the head of this bone. The long tendon of the
Biceps muscle which passes through the joint, is enclosed in a tubular sheath of
synovial membrane, which is reflected upon it at the point where it perforates the
capsule, and is continued around it as far as the summit of the glenoid cavity,
where it is continuous with that portion of the membrane which covers its surface.
The tendon of the Biceps is thus enabled to traverse the articulation, but is not
contained in the interior of the synovial cavity. The synovial membrane commu-
nicates with a large bursal sac beneath the tendon of the Sub-scapularis, by an
opening at the inner side of the capsular ligament; it also occasionally communi-
cates with another bursal sac, beneath the tendon of the Infra-spinatus, through an
orifice Tit its upper part. A third bursal sac, which does not communicate with
the joint is placed between the under surface of the deltoid and the outer surface
of the capsule.
The Muscles in relation with this joint are, above, the Supra-spinatus; below,
the long tendon of the Triceps; internally, the Sub-scapularis; externally, the Infra-
spinatus and Teres minor; within, the long tendon of the Biceps. The Deltoid is
placed most externally, and covers the articulation on its outer side, and in front
and behind.
The Arteries supplying this joint are articular branches of the anterior and
posterior circumflex, and supra- scapular.
The Nerves are dei'ived from the cir-
cumflex and supra-scapular.
Actions. The shoulder joint is capable
of movement in almost any direction, for-
wards, backwards, abduction, adduction,
circumduction, and rotation.
5. Elbow Joint.
The Elbow is a gi?igli/nioid or hinge
joint. The bones entering into its forma-
tion are the trochlear surface of the
humerus, which is received in the greater
sigmoid cavity of the ulna, and admits
of the movements peculiar to this joint,
those of flexion and extension, whilst the
cup-shaped depression of the head of the
radius articulates with the radial tubero-
sity of the humerus, its circumference Avith
the lesser sigmoid cavity of the ulna, al-
lowing of the movement of I'otation of the
radius on the ulna, the chief action of the
superior radio-ulnar articulation. These
various articular surfaces are covered with
a thin layer of cartilage, and connected
together by the following ligaments.
Anterior Ligament.
Posterior Ligament.
Internal Lateral.
External Lateral,
Synovial Membrane.
The Anterior Ligament (fig. 115) is a
broad and thin membranous layer, which
covers the anterior surface of the joint.
It is attached to the humerus immediately
1 1 5. — Left Elbow- Joint, showing Anterior
and Internal Ligaments.
1 62
ARTICULATIONS.
1 1 6. — Left Elbow-Joint, shewing Pos-
terior and External Licraments.
above the coronoid fossa; below, to the anterior surface of the coronoid process of
the ulna and orbicular ligament, being continuous on each side with the lateral
ligaments. Its superficial or oblique fibres pass from the internal tuberosity of
the humerus outwards to the orbicular ligament. The middle fibres, vertical
in direction, pass from the upper part of the coronoid depression, and become
blended with the preceding. A third, or transverse set, intersect these at right
angles. This ligament is in relation, in front, with the Brachialis anticus; behind,
with the synovial membrane.
The Posterior Ligament is a thin and loose membranous fold, attached, above,
to the lower end of the humerus, immediately above the olecranon depression;
below, to the margin of the olecranon. The superficial or transverse fibres pass
between the adjacent margins of the olecranon fossa. The deeper portion consists
of vertical fibres, which pass from the upper pa^rt of the olecranon fossa to the
margin of the olecranon. This ligament is in relation, behind, with the tendon of
the Triceps and Anconeus; in front, with the synovial membrane.
The Internal Lateral I^igament is a thick triangular band of ligamentous
fibres, consisting of two distinct portions, an anterior and posterior. The ante-
rior portion, directed obliquely forwards, is attached, above, by its apex, to
the front part of the internal condyle of the humerus; and, below, by its broad
base to the inner margin of the coronoid process. The posterior portion, also of
triangular form, is attached, above, by its apex to the lower and back part of the
internal condyle; below, to the inner margin of the olecranon. This ligament is
in relation, internally, with the Triceps and Flexor carpi ulnaris muscles and the
ulnar nerve.
The External Lateral lAgament (fig. 1 1 6) is a short and narrow fibrous fasci-
culus, less distinct than the internal, attached,
above, to the external condyle of the hume-
rus; below, to the orbicular ligament, some
of its most posterior fibres passing over that
ligament to be inserted into the outer margin
of the greater sigmoid cavity. This ligament
is intimately blended with the tendon of origin
of the Supinator brevis muscle.
The Synovial Membrane is very extensive.
It covers the articular surface of the humerus,
and lines the coronoid and olecranon depres-
sions on that bone ; from these points, it is
reflected over the anterior, posterior and lateral
ligaments; lines the greater sigmoid cavity, the
concave depression on the head of the radius;
and forms a pouch between the lesser sigmoid
cavity, the internal surface of the annular liga-
ment, and the circumference of the radius.
The Muscles in relation with this joint are,
in front, the Brachialis anticus; behind, the
Triceps and Anconeus; externally, the Supina-
tor brevis, and the common tendon of origin of
the Extensor muscles; internally, the common
tendon of origin of the Flexor muscles, the
Flexor carpi ulnaris, and ulnar nerve.
The Arteries supplying this joint are derived
from the communicating branches between the
superior profunda, inferior profunda, and ana-
stomatic branches of the Brachial, with the
anterior, posterior and interosseous recurrent
branches of the Ulnar, and the recurrent branch
of the Radial. These vessels form a complete
chain of inosculation around this joint.
RADIO-ULNAR. 163
The Nerves are derived from the ulnar, as it passes between the internal condyle
and the olecranon.
Actio?is. The elbow is one of the most perfect hinge-joints in the body; its
movements are consequently limited to flexion and extension, the exact apposition
of the articular surfaces preventing the least lateral motion. The movement of
flexion is limited by the coronoid process, and that of extension by the olecranon
process.
6. Radio-Ulnar Articulations.
The articulation of the radius with the ulna is effected by ligaments, which
connect together both extremities as well as the centre of these bones. They may,
consequently, be subdivided into three sets: I, the superior radio-ulnar; 2, the
middle radio-ulnar; and, 3, the inferior radio-ulnar articulations.
1. Superior Radio-Ulnar Articulation.
This articulation is a lateral ginglymoid joint. The bones entering into its
formation are the inner side of the circumference of the head of the radius, which
is received into the lesser sigmoid cavity of the ulna. These surfaces are covered
with cartilage, and invested with a duplicature of synovial membrane, continuous
with that which lines the elbow-joint. Its only ligament is
The Annular or Orbicular.
The Orbicular Ligament {^g. II 6) is a strong flat band of ligamentous fibres, which
surrounds the head of the radius, and retains it in firm connection with the lesser
sigmoid cavity of the ulna. It forms about three-fourths of a fibrous ring, attached
by each end to the extremities of this cavity, and is broader at the upper part of
its circumference than below, which serves to hold the head of the radius more
securely in its position. Its outer surface is strengthened by the external lateral
ligament, and affords partial origin to the Supinator brevis mwscle. Its internal
surface is smooth, and lined by the synovial membrane of the elbow-joint.
Actions. The movement which takes place in this articulation is limited to rota-
tion of the inner part of the head of the radius within the orbicular ligament, and
upon the lesser sigmoid cavity of the ulna; rotation forwards being called prona-
tion; rotation backward, supination.
2. Middle Radio-Ulnar Articulation.
The interval between the radius and ulna in the middle of the forearm is occu-
pied by two ligaments.
Oblique. Interosseous.
The Oblique or Round Ligament (fig. 115) is a small round fibrous cord, which
extends obliquely downwards and outwards, from the tubercle of the ulna at the
base of the coronoid process, to the radius a little below the bicipital tuberosity.
Its fibres run in the opposite direction to those of the interosseous ligament; and
it appears to be placed as a substitute for it in the upper part of the interosseous
interval.
The Interosseous Ligament is a broad and thin plane of aponeurotic fibres, de-
scending obliquely downwards and inwards, from the interosseous ridge on the
radius to that on the ulna. It is deficient above, commencing about an inch be-
neath the tubercle of the radius; broader in the middle than at either extremity;
and presents an oval aperture just above its lower margin for the passage of the
anterior interosseous vessels to the back of the forearm. This ligament serves to
connect the bones, and to increase the extent of surface for the attachment of the
deep muscles. Between its upper border and the oblique ligament an interval
exists, through which the posterior interosseous vessels pass. Two or three fibrous
bands are occasionally found on the posterior surface of this membrane, which
M 2
1 64 ARTICULATIONS.
descend obliquely from the ulna towards the radius, and which have consequently
a direction contrary to that of the other fibres. It is in relation, in front, by its
upper three-fourths (radial margin) with the Flexor longus pollicis (ulnar margin),
with the Flexor profundus digitorum (lying upon the interval between which are
the anterior interosseous vessels and nerve), by its lower fourth with the Pronator
quadratus; behind, with the Supinator brevis. Extensor ossis metacarpi pollicis,
Extensor primi internodii pollicis. Extensor secundi internodii pollicis. Extensor
indicis; and, near the wrist, with the anterior interosseous artery and posterior
interosseous nerve.
3. Inferior Radio-Ulnar Articulation.
This is a lateral ginglymoid joint, formed by the head of the ulna being received
into the sigmoid cavity at the inner side of the ' lower end of the radius. The
articular surfaces are invested by a thin layer of cartilage, and connected together
by the following ligaments.
Anterior radio-ulnar.
Posterior radio-ulnar.
Triangular Inter-articular Fibro-cartilage.
, Synovial Membrane.
The Anterior Radio-ulnar Ligament (fig. 117) is a narrow band of fibres, ex-
tending from the anterior margin of the sigmoid cavity of the radius to the ante-
rior surface of the head of the ulna.
Q\ The Posterior Radio-ulnar Ligament (ijg. 118) extends between the same
points on the posterior surface of the articulation.
The Lnter-articular Fibro-cartilage (fig. i ig^-is a thick fibro-cartilaginous lamella,
of a triangular form, placed transversely, completing the wrist-joint, and binding
the lower ends of the radius and ulna firmly together. Its circumference is more
dense than its centre, which is thin and occasionally perforated; and it is thinner
and broader extei^ially than internally. It is attached by its apex to a depres-
sion which separates the styloid process of the ulna from the head of that bone;
by its base, which is thin, to the prominent edge of the radius, which sepa-
rates the sigmoid cavity from the carpal articulating surface, and by its anterior
and posterior margins to the ligaments of the radio-carpal articulation. Its
upper surface, smooth and concave, is contiguous with the head of the ulna; its
under surface, also concave and smooth, with the cuneiform bone. Both surfaces
are lined by a synovial membrane: the superior surface, by one peculiar to the
radio-ulnar ^.rticulation ; the inferior surface, by the synovial membrane of the
wrist.
The Synovial Membrane of this articulation has been called, from its extreme
looseness, the membrana sacciformis; it covers the articular surface of the head
of the ulna, and where reflected from this bone on to the radius, forms a very loose
cul-de-sac; from the radius it is continued over the upper surface, of the fibro-
cartilage. The quantity of synovia which it contains is usually considerable.
When the fibro-cartilage is perforated, this synovial membrane is continuous with
that which lines the wrist-joint.
Actions. The movement which occurs in .the inferior radio-ulnar articulation is
just the inverse of that which takes place between the two bones above; it is limited
to rotation of the radius around the head of the nlna; rotation forwards being
termed pronation, rotation backwards supination. In pronation, the sigmoid cavity
glides forward on the articular edge of the ulna; in supination, it rolls in the
opposite direction, the extent of these movements being limited by the anterior
and posterior ligaments.
7. Wrist Joint.
The Wrist presents most of the characters of an enarthrodial joint. The parts
entering into its formation are the lower end of the radius, and under surface
WRIST JOINT.
165
of the triangular interarticular fibro-cartilage, above; and the scaphoid, eomilunar,
and cuneiform bones below. The articular surfaces of the radius and interarticular
117. — Ligaments of Wrist and Hand. Anterior View.
INFERIOR RADIO-Ui-NAR ARTIC"
WRIST-JOiNT
CARPAL ARTICJ?
CARPO-METACARPAL ARTIC '
fibro-cartilage form a transversely elliptical concave surface. The radius is sub-
divided into two parts by a line extending from before backwards; and these,
together with the interarticular cartilage, form three facets, one for each carpal
1 18. — Ligaments of Wrist and Hand. Posterior View.
Carp o-MMctcaimal /y j
bone. The three carpal bones are connected together, and form a rounded convex
surface, which is received into the cavity above mentioned. All the bony surfaces
1 66 ARTICULATIONS.
of this articulation are covered with cartilage, and connected together by the
following ligaments.
External Lateral. Anterior.
Internal Lateral. Posterior.
Synovial Membrane.
The External Lateral Ligament extends from the summit of the styloid pro-
cess of the radius to the outer side of the scaphoid, some of its fibres being
prolonged to the trapezium and annular ligament.
The Internal Lateral Ligament is a rounded cord, attached, above, to the ex-
tremity of the styloid process of the ulna; below, it divides into two fasciculi,
which are attached, one to the inner side of the cuneiform bone, the other to the
pisiform bone and annular ligament.
The Anterior Ligament is a broad membranous band, consisting of three fasci-
culi, attached, above, to the anterior margin of the lower end of the radius, its
styloid process, and the ulna; its fibres pass downwards and inwards, to be
inserted into the anterior surface of the scaphoid, semilunar, and cuneiform bones.
This ligament is perforated by numerous apertures for the passage of vessels, and
is in relation, in front, with the tendons of the Flexor profundus digitorum and
Flexor longus pollicis; behind, with the synovial membrane of the wrist-joint.
The Posterior Ligament, less thick and strong than the anterior, is attached,
above, to the posterior border of the lower end of the radius; its fibres descend
obliquely downwards and inwards to be attached to the posterior surface of the
scaphoid, semilunar, and cuneiform bones, its fibres being continuous with those
of the dorsal carpal ligaments. This ligament is in relation, behind, with the
extensor tendons of the fingers; in front, with the synovial membrane of the
wrist.
The Synovial Membrane lines the lower end of the radius and under surface of
the triangular inter-articular fibro-cartilage above; and being reflected on the
inner surface of the ligaments above mentioned, covers the convex surface of the
scaphoid, semilunar, and cuneiform bones below.
Relations. The wrist-joint is covered in front by the flexor, and behind by the
extensor tendons; it is also in relation with the radial and ulnar arteries.
The Arteries supplying this joint are the anterior and posterior carpal branches
of the Radial and Ulnar, the anterior and posterior interosseous, and some
ascending branches from the deep palmar arch.
The Nerves are derived from the posterior interosseous.
Actions. The movements permitted in this joint are flexion, extension, abduc-
tion, adduction, and circumduction. It is totally incapable of rotation, one of the
characteristic movements in true enarthrodial joints.
8. Articulations of the Carpus.
These articulations may be subdivided into three sets.
1. The articulation of the first row of carpal bones.
2. The articulation of the second row of carpal bones.
3. The articulation of the two rows with each other.
I. Articulation of the First Row of Carpal Bones.
These are arthrodial joints. The articular surfaces are covered with cartilage,
and connected together by the following ligaments.
Two Dorsal. Two Palmar.
Two Interosseous.
The Dorsal Ligaments, two in number, are placed transversely behind the bones
of the first row; they connect the scaphoid and semilunar, and the semilunar and
■ cuneiform.
The Palmar Ligaments, also two in number, connect the scaphoid and semi-
I
OF THE CARPUS. 167
lunar, and the semilunar and cuneiform bones; they are less strong than the dorsal,
and placed very deep under the anterior ligament of the wrist.
The Interosseous Ligaments (fig. 1 19) are two narrow bundles of dense fibrous
tissue, connecting the semilunar bone, on one side with the scaphoid, on the other
with the cuneiform bone. They close the upper part of the interspaces between
the scaphoid, semilunar, and cuneiform bones, their upper surfaces being smooth,
and lined by the synovial membrane of the wrist-joint.
The articulation of the pisiform with the cuneiform is provided with a separate
synovial membrane, protected by a thin capsular ligament. There are also two
strong fibrous fasciculi, which connect this bone to the unciform, and base of the
fifth metacarpal bone.
2. Articulation of the Second Row or Carpal Bones.
These are also arthrodial joints, the articular surfaces being covered with carti-
lage, and connected by the following ligaments.
Three Dorsal. Three Palmar.
Two Interosseous.
The three Dorsal Ligaments extend transversely from one bone to another on
the dorsal surface, connecting the trapezium with the trapezoid, the trapezoid with
the OS magnum, and the os magnum with the unciform.
The three Palmar Ligaments have a similar arrangement on the palmar surface.
The tioo Interosseous Ligaments, much thicker than those of the first row, are
placed one on each side of the os magnum, connecting it with the trapezoid exter-
nally, and the unciform internally. The former is less distinct than the latter.
3. Articulation of the Two Rows of Carpal Bones with each other.
The articulation between the two rows of the carpus consists of an enarthrodial
joint in the middle, formed by the reception of the os magnum into a cavity
formed by the scaphoid and semilunar bones, and of an arthrodial joint on each
side, the outer one formed by the articulation of the scaphoid with the trapezium
and trapezoid, the internal one by the articulation of the cuneiform and unciform.
The articular surfaces are covered by a thin layer of cartilage, and connected by
the following ligaments.
Anterior or Palmar. External Lateral.
Posterior or Dorsal. Internal Lateral.
Synovial Membranes.
The Anterior or Palmar Ligaments consist of short fibres, which pass obliquely
between the bones of the first and second row on the palmar surface.
The Posterior or Dorsal Ligaments have a similar arrangement on the dorsal
surface of the carpus.
The Lateral Ligaments are very short; they are placed, one on the radial, the
other on the ulnar side of the carpus; the former, the stronger and more distinct,
connecting the scaphoid and trapezium bones, the latter the cuneiform and unci-
form: they are continuous with the lateral ligaments of the wrist-joint.
There are two Synovial Membranes found in the articulation of the carpal
bones with each other. The first of these, the more extensive, lines the under
surface of the scaphoid, semilunar, and cuneiform bones, sending upwards two
prolongations between their contiguous surfaces; it is then reflected over the
bones of the second row, and sends down three prolongations between them, which
line thfeir contiguous surfaces, and invest the carpal extremities of the four outer
metacarpal bones. The second is the synovial membrane between the pisiform
and cuneiform bones.
Actions. The partial movement which takes place between the bones of each
row is very inconsiderable; the movement between the two rows is more marked,
but limited chiefly to flexion and extension.
1 68
ARTICULATIONS.
9. Carpo Metacarpal Articulations.
Articulation of the First Metacarpal Bone with the Trapezium.
This is an enarthrodial joint. Its ligaments are a capsular and synovial mem-
brane. The capsular ligament is a thick but loose capsule, which passes from
the circumference of the upper extremity of the metacarpal bone, to the rough
edge bounding the articular surface of the trapezium; it is thickest externally and
behind, and lined by a separate synovial membrane.
Articulation of the Four inner Metacarpal Bones with the Carpus.
The joints formed between the carpus and four inner metacarpal bones, are con-
nected together by dorsal, palmar, and interosseous ligaments.
The Dorsal Ligaments, the strongest and most distinct, connect the carpal and
metacarpal bones on their dorsal surface. The second metacarpal bone receives
two fasciculi, one from the trapezium, the other from the trapezoid; the third me-
tacarpal receives one from the os magnum; the fourth two, one from the os mag-
num, and one from the unciform; the fifth receives a single fasciculus from the
imciform bone.
The Palmar Ligaments have a somewhat similar arrangement on the palmar
surface, with the exception of the third metacarpal, which has three ligaments, an
external one from the trapezium, situated above the sheath of the tendon of the
Flexor carpi radialis ; a middle one, from the os magnum ; and an internal one, from
the unciform.
The Interosseous Ligaments consist of short thick fibres, which are limited to
one part of the carpo-metacarpal articulation; they connect the inferior angles of
the OS magnum and unciform, with the adjacent surfaces of the third and fourth
metacarpal bones.
The Synovial 3Iembrane is a continuation of that between the two rows of
carpal bones. Occasionally the unciform has a separate synovial membrane, lining
it and the fourth and fifth metacarpal bones.
The Synovial Membranes of the wrist (fig. 119) are thus seen to be five in
119. — Vertical Section through the Articulations at the Wrist, showing the five
Synovial Membranes.
CARPO-METACARPAL AND METACARPO-PHALANGEAL. 169
number. The first, the membrana sacciformis, lining the lower end of the ulna,
the sigmoid cavity of the radius, and upper surface of the triangular inter-articular
iibro-cartilage. The second lines the lower end of the radius and inter-articular
fibro-cartilage above, and the scaphoid, semilunar, and cuneiform bones below. The
third, the most extensive, covers the contiguous surfaces of the two rows of carpal
bones, and passing between the bones of the second range, lines the carpal extre-
mities of the four inner metacarpal bones. The fourth lines the adjacent sur-
fiices of the trapezium and metacarpal bone of the thumb. And the fifth the
adjacent surfaces of the cuneiform and pisiform bones.
Actions. The movement permitted in the carpo-metacarpal articulations is limited
to a slight gliding of the articular surfaces upon each other, the extent of which
varies in the diiFerent joints. Thus the articulation of the metacarpal bone of the
thumb with the trapezium is most moveable, then the fifth metacarpal, and then
the fourth. The second and third are almost immoveable. In the articulation of
the metacarpal bone of the thumb with the trapezium, the movements permitted
are flexion, extension, adduction, abduction, and circumduction.
Articulation of the Metacaepal Bones with each other.
The carpal extremities of the metacarpal bones of the fingers, articulate with
one another at each side by small surfaces covered with cartilage, and connected
together by dorsal, palmar, and interosseous ligaments.
The Dorsal or Palmar Ligaments pass transversely from one bone to another
on the dorsal and palmar surfaces. The Interosseous Ligaments passing between
their contiguous surfaces, just beneath their lateral articular facets.
The Synovial Membrane lining the lateral facets, is a reflection of that between
the two rows of carpal bones.
The digital extremities of the metacarpal bones of the fingers, are connected
together by the transverse ligament, a narrow fibrous band, passing transversely
across their under surfaces, and blended with the ligaments of the metacarpo-pha-
langeal articulations. Its anterior surface presents four grooves for the passage
of the flexor tendons, and its sides are continuous with their sheaths. Its poste-
rior surface blends with the ligaments of the metacarpo-phalangeal articulation.
10. Metacarpo-phalangeal Articulations (fig. 120).
These ai-ticulations are of the ginglymoid kind, formed by the reception of each
of the rounded heads of the metacarpal bones of the four fingers, into a superficial
cavity in the extremity of the first phalanges. They are connected by the fol-
lowing ligaments,
Anterior. Two Lateral.
Synovial Membrane.
The Anterior Ligaments are very thick and dense, they are placed on the
palmar surface of the joint in the interval between the lateral ligaments, to which
they are connected; they are loosely united to the metacarpal bone, but very
firmly to the base of the first phalanges. Their palmar surface is intimately
united to the transverse ligament, each ligament forming with it a groove for the
passage of the flexor tendons, the sheath surrounding which is connected to it at
each side. By their internal surface they form part of the articular surface for
the head of the metacarpal bone, and are lined by a synovial membrane.
The Lateral Ligaments are thick and strong rounded cords, placed one on each
side of the joint, attached by one extremity to the sides of the head of the meta-
carpal bones, and by the other, to the contiguous extremity of the phalanges.
The Posterior Ligament is supplied by the extensor tendon of the fingers placed
over the back of each joint.
Actions. The movements which occur in these joints are flexion, extension,
adduction, abduction, and circumduction ; the lateral movements are very limited.
170
ARTICULATIONS.
LATERAL LICAMCNT-
Metacar^o - jJuvla.Tic/ml
1 1 . Articulations of the Phalanges.
These are ginglymoid joints, connected by the following ligaments;
120.— Articulations of the Phalanges. ;^"*^ x^^/ .
iwo Lateral.
Synovial Membrane.
The arrangement of these liga-
ments is similar to those in the
preceding articulations; the exten-
sor tendon supplies the place of a
posterior ligament.
Actions. The only movements
permitted in the phalangeal joints
are flexion and extension; these
movements are more extensive be-
tween the first and second phalanges
than between the second and third.
The movement of flexion is very ex-
tensive, but extension is limited by
the anterior and lateral ligaments.
ARTICULATIONS OF THE
LOWER EXTREMITY.
'The articulations of the lower
extremity comprise the following
groups. I. The hip joint. 2. The
knee joint. 3. The articulations
between the tibia and fibula.
4. The ankle joint. 5. The arti-
culations of the tarsus. 6. The
tarso-metatarsal articulations. 7.
The metatarso phalangeal articula-
tions. 8. The articulation of the
phalanges.
I. Hip Joint, (fig. 121).
This articulation is an enarthro-
dial, or ball and socket joint, formed by the reception of the globular head of
the femur into the cup-shaped cavity of the acetabulum. These two articulating
surfaces are covered with cartilage, that on the head of the femur being thicker
at the centre than at the circumference, and covering the entire surface with the
exception of a depi-ession just below its centre for the ligamentum teres; that
covering the acetabulum is much thinner at the centre than at the circumference,
and is deficient in the situation of the circular depression at the bottom of this
cavity. The ligaments of this joint are the •
Capsular. Cotyloid.
Uio-femoral. Transverse.
Teres. Synovial Membrane.
The Capsular Ligament is a strong, dense, ligamentous capsule, embracing the
margin of the acetabulum above, and surrounding the neck of the femur below.
Its upper circumference is attached to the acetabulum two or three lines extei'nal
to the cotyloid ligament; but opposite the notch where the margin of this cavity
is deficient, it is connected with the transverse ligament, and by a few fibres to the
edge of the obturator foramen. Its lower circumference surrounds the neck of
PJi eoTa,ji (f eal
Artie Vf
HIP JOINT.
171
the femur, being attached, in front, to the spiral or anterior inter-trochanteric line;
above, to the base of the neck; behind, to the middle of the neck of the bone,
about thi'ee quarters of an inch from the posterior inter-trochanteric line. It is
izi. — Left Hip Joint laid open.
much thicker at the upper and anterior part of the joint where the greatest amount
of resistance is required, than below, where it is thin, loose, and longer than in
any other situation. Its external surface is rough, covered by numerous muscles,
and separated in front from the Psoas and Iliacus by a synovial bursa, which not
unfrequently communicates by a circular aperture with the cavity of the joint. It
differs from the capsular ligament of the shoulder, in being much less loose and
lax, and in not being perforated for the passage of a tendon.
The Ilio-femoral Ligament (fig. no) is an accessory band of fibres, extending
obliquely across the front of the joint: it is intimately connected with the capsular
ligament, and serves to strengthen it in this situation. It is attached above to the
anterior inferior spine of the ilium, below, to the anterior inter-trochanteric line.
The Ligamentum Teres is a flat triangular band of fibres, implanted by its
apex into the depression just below the middle of the head of the femur, and by
its broad base, which consists of two bundles of fibres, into the margins of the
notch at the bottom of the acetabulum, becoming blended with the transverse
ligament. It is formed of a bundle of fibres, the thickness and strength of which
is very variable, surrounded by a tubular sheath of synovial membrane. Some-
times the synovial fold only exists, or the ligament may be altogether absent.
The Cotyloid Ligament is a fibro-cartilaginous rim attached to the margin of the
acetabulum, the cavity of which it deepens, at the same time it protects the edges
of the bone, and fills up the inequalities on its surface. It is prismoid in form, its
base being attached to the margin of the acetabulum, its opposite edge being free
and sharp; whilst its two surfaces are invested by synovial membrane, the external
172
ARTICULATIONS.
one being in contact with the capsular ligament, the internal being inclined inwards
so as to narrow the acetabulum and embrace the cartilaginous surface of the head
of the femur. It is much thicker above and behind than below and in front, and
consists of close, compact fibres, which arise from different points of the circum-
ference of the acetabulum, and interlace with each other at very acute angles.
The Transverse Ligament is a strong flattened band of fibres, which crosses
the notch at the lower part of the acetabulum, and converts it into a foramen. It
is continuous at each side with the cotyloid ligament, and consists of fibres which
arise from each side of the notch, and pass across each other. An interval is left
beneath this ligament for the passage of nutrient vessels to the joint.
The Synovial Membrane is very extensive. It invests the cartilaginous sur-
face of the head of the femur, and all that portion of the neck which is contained
within the joint; from this point it is reflected on the internal surface of the cap-
sular ligament, covers both surfaces of the cotyloid ligament, and lines the cavity
of the acetabulum, covers the mass of fat contained in the fossa at the bottom of
this cavity, and is prolonged in the form of a tubular sheath around the liga-
nientum teres on to the head of the femur.
The Muscles in relation with this joint are, in front, the Psoas and Iliacus,
separated from the capsular ligament by a synovial bursa; above, the short head of
the Rectus and Gluteus minimus, the latter being closely adherent to it; internally,
the Obturator externus and Pectineus; behind, the Pyriformis, G-emellus superior,
Obturator internus. Gemellus inferior. Obturator externus, and Quadratus femoris.
The Arteries supplying it are derived from the obturator, sciatic, internal cir-
cumflex, and gluteal.
The Nerves are articular branches from the sacral plexus, great sciatic, obtu-
rator, and accessory obturator nerves.
Actions. The movements of
122. — Eight Knee Joint.
the hip, like all enarthrodial
joints, are very extensive; they
are flexion, extension, adduction,
abduction, circumduction, and
rotation.
2. The Knee Joint.
The knee is a ginglymoid, or
hinge joint; the bones entering
into its formation are the con-
dyles of the femur above, the
head of the tibia below, and the
patella in front. The articular
surfaces are covered with car-
tilage, lined by synovial mem-
brane, and connected together
by ligaments, some of which are
placed on the exterior of the
joint, whilst others occupy its
interior.
External Ligaments.
Anterior, or Ligamentum Pa-
tellae.
Posterior, or Ligamentum Pos-
ticum Winslowii.
Internal Lateral.
Two External Lateral.
Capsular.
Anterior View.
KNEE JOINT.
173
Internal Ligaments.
Anterior, or External Crucial. Two Semilunar Fibro-cartilages.
Posterior, or Internal Crucial. Transverse.
Coronary.
„ . 1 T,*- , ( Liffamentum mucosum.
Synovial Membrane. s t • x i •
"^ ( Ligamenta aiaria.
Tlie Anterior Ligament, or Ligamentum Patellce (fig. 122), is that portion of the
common tendon of the extensor muscles of the thigh v^hich is continued from the
patella to the tubercle of the tibia, supplying the place of an anterior ligament.
It is a strong, flat, ligamentous band, attached, above, to the apex of the patella
jind the rough depression on its posterior surface; below, to the lower part of the
tuberosity of the tibia; its superficial fibres being continuous across the front of
the patella with those of the tendon of the Rectus femoris. Two synovial bursas
are connected with this ligament and the patella; one is interposed between the
patella and the skin covering its anterior surface; the other, of small size, between
the ligamentum patellce and the upper part of the tuberosity of the tibia. The
posterior surface of this ligament is separated above from the knee joint by a
large mass of adipose tissue, its lateral margins are continuous with the aponeu-
roses derived from the Vasti muscles.
The Posterior Ligament, Li-
gamentum Posticum Winsloioii i^s.-^igbt-Knee Joint. Posterior View.
(fig. 123), is a broad, flat, fibrous
band, which covers over the
whole of the back part of the
joint. It consists of two lateral
portions, formed chiefly of ver-
tical fibres, which arise above
from the condyles of the femur,
and connected below with the
back part of the head of the tibia,
being closely united with the
tendons of the Gastrocnemii,
Plantaris, and Popliteus muscles;
the central portion is formed of
fasciculi obliquely directed and
separated from one another by
apertures for the passage of
vessels. The strongest of these
fasciculi is derived from the
tendon of the Semi-membranosus,
it passes from the back part of
the inner tuberosity of the tibia,
obliquely upwards and outwards
to the back part of the outer
condyle of the femur. The
posterior ligament forms part of
the floor of the popliteal space,
and upon it rests the popliteal
artery.
The Internal Lateral Ligament is a broad, flat, membranous band, thicker
behind than in front, and situated nearer to the back than the front of the
joint. It is attached, above, to the inner tuberosity of the femur; below, to the
inner tuberosity and inner surface of the shaft of the tibia, to the extent of about
two inches. It is crossed, at its lower part, by the aponeurosis of the Sartorius,
and the tendons of the Gracilis and Semi-tendinosus -muscles, a synovial bursa
being interposed. Its deep surface covers the anterior portion of the tendon of
174
ARTICULATIONS.
the Semi-membranosus, the synovial membrane of the joint, and the inferior inter-
nal articular artery; it is intimately adherent to the internal semi-lunar fibro-
cartilage.
The Long External Lateral Ligament is a strong, rounded, fibrous cord,
situated nearer the posterior part of the articulation than the anterior. It is
attached, above, to the outer tuberosity of the femur; belovs^, to the outer part of
the head of the fibula. Its outer surface is covered by the tendon of the Biceps,
which divides into two parts, separated by this ligament, at its insertion. It has,
passing beneath it, the tendon of the Popliteus muscle, and the inferior external
articular artery.
The Short External Lateral Ligament is an accessory bundle of fibres, placed
behind and parallel with the preceding; attached, above, to the lower part of the
outer tuberosity of the femur; below, to the summit of the styloid process of the
fibula. This ligament is intimately connected with the capsular ligament, and
has passing beneath it the tendon of the Popliteus muscle.
The Capsular Ligament consists of an exceedingly thin, but strong, fibrous
membrane, which surrounds the joint in the intervals left by the preceding liga-
ments, being attached to the femur immediately above its articular surface ;
below, to the upper border and sides of the patella, the margins of the head of
the tibia and inter-articular cartilages, and being continuous behind with the pos-
terior ligament. This membrane is strengthened by fibrous expansions, derived
from the fascia lata and Yasti muscles, at their insertion into the sides of the
patella.
The Crucial are two interosseous ligaments of very considerable strength,
situated in the interior of the joint, nearer its posterior than its anterior part.
They ai'e called crucial, because they cross each other, somewhat like the lines of
124. — Eight Knee-Joint. Shewing Internal Ligaments.
F e :
SUPERIOR
•riBULAH ABTICl
KNEE JOINT.
175
125. — Head of Tibia, with Semi-lunar
Cartilages, etc. Seen from above.
Eight Side.
the letter X; and have received the names anterior and posterior, from the posi-
tion of their attachment to the tibia.
The Anterior or External Crucial Ligament (fig. 124), smaller than the poste-
rior, arises from the inner side of the depression in front of the spine of the tibia,
being blended with the anterior extremity of the external semi-lunar fibro-carti-
lage, and passing obliquely upwards, backwarks, and outwards, is inserted into
the inner and back part of the outer condyle of the femur.
The Posterior or Internal Crucial Ligament is larger in size, but less oblique
in its direction than the anterior. It arises from the back part of the depression
behind the spine of the tibia, and from the posterior extremity of the external
semi-lunar fibro-cartilage ; passing upwards, forwards, and inwards, it is inserted
into the outer and front part of the inner condyle of the femur. As it crosses the
anterior crucial ligament, a fasciculus is given off from it, which blends with its
posterior part. It is in relation, in front, with the anterior ligament; behind,
with the ligamentum posticum Winslowii.
The Semi-lunar Fibro- Cartilages (fig. 125) are two crescentic lamellae attached
to the margins of the head of the tibia, serving to deepen its surface for articula-
tion with the condyles of the femur. The
circumference of each cartilage is thick and
convex ; the inner free border, thin and con-
cave. Their upper surfaces are concave, and
in relation with the condyles of the femur;
their lower surfaces are flat, and rest upon
the head of the tibia. Each cartilage covers
nearly the outer two-thirds of the corre-
sponding articular surface of the tibia, the
inner third being uncovered; both surfaces
are smooth, and invested by synovial mem-
brane.
The Internal Semi-lunar Fibro- Cartilage
is nearly semicircular in form, a little elon-
gated from before backwards, and broader behind than in front; its convex border
is united to the internal lateral ligament, and to the head of the tibia, by means of
the coronary ligaments; its anterior extremity, thin and pointed, is firmly im-
planted into the depression in front of the spine of the tibia; its posterior extre-
mity to the depression behind the spine.
The External Semi-lunar Fibro- Cartilage forms nearly an entire circle, cover-
ing a larger portion of the articular surface than the internal one. It is grooved
on its outer side, for the tendon of the Popliteus muscle. Its circumference is
held in connexion with the head of the tibia, by means of the coronary ligaments;
and by its two extremities is firmly implanted in the depressions in front and
behind the spine of the tibia. These extremities, at their insertion, are interposed
between the attachments of the internal cartilage. The external semi-lunar fibro-
1 cartilage gives off from its anterior border a fasciculus, which forms the trans-
' verse ligament. By its anterior extremity, it is continuous with the anterior
crucial ligament. Its posterior extremity divides into three slips ; one, a
strong cord, passes upwards and forwards, and is inserted into the outer side of
the inner condyle, in front of the posterior crucial ligament; another fasciculus is
inserted into the outer side of the inner condyle, behind the posterior crucial
•ligament; a third fasciculus is inserted into the back part of the anterior crucial
[ ligament.
The Transverse Ligament is a band of fibres, which passes transversely between
I the anterior convex margin of the external cartilage, to the anterior extremity of
jthe internal cartilage; its thickness varies considerably in different subjects.
The Coronary Ligaments consist of numerous short fibrous bands, which con-
inect the convex border of the semi-lunar cartilages with the circumference of the
head of the tibia, and with the other ligaments surrounding the joint.
176 ARTICULATIONS.
The Synovial Membrane of the knee-joint is the largest and most extensive in
the body. Commencing at the upper border of the patella, it forms a large cul-
de-sac beneath the Extensor tendon of the thigh: this is sometimes replaced
by a synovial bursa interposed between this tendon and the femur, which in
some subjects communicates with the synovial membrane of the knee-joint, by an
orifice of variable size. On each side of the patella, the synovial membrane
extends beneath the aponeuroses of the Vasti muscles, and more especially beneath
that of the Vastus internus; it covers the surface of the patella itself, and, beneath
it, is separated from the anterior ligament by a considerable quantity of adipose
tissue. In this situation, it sends oif a triangular- shaped prolongation, containing
a few ligamentous fibres, which extends from the anterior part of the joint below
the patella, to the front of the inter-condyloid notch. This fold has been termed
the ligamentum mucosum. The ligamenta alaria consist of two fringe-like
folds, which extend from the sides of the ligamentum mucosum, upwards and out-
wards, to the sides of the patella. The synovial membrane covers both surfaces
of the semi-lunar fibro-cartilages, and on the back part of the external one forms
a cul-de-sac between the groove on its surface and the tendon of the Popliteus;
it covers the articular surface of the tibia; surrounds the crucial ligaments, and
inner surface of the ligaments which enclose the joint; lastly, it covers the entire
surface of the condyles of the femur, and from them is continued on to the lower
part of the front surface of the shaft. The pouch of synovial membrane between
the Extensor tendons and front of the femur is supported, during the movements
of the knee, by a small muscle, the Sub-crurseus, which is inserted into it.
The Arteries supplying this joint are derived from the anastomotic branch of
the Femoral, articular branches of the Popliteal, and recurrent branch of the Ante-
rior Tibial.
The Nerves are derived from the obturator and external and internal popliteal.
Actions. The chief movements of this joint are flexion and extension; but it is
also capable of performing some slight rotatory movement. During flexion, the
articular surfaces of the tibia, covered by their inter-articular cartilages, glide
backwards upon the condyles of the femur, the lateral posterior and crucial liga-
ments are relaxed, the ligamentum patellae is put upon the stretch, the patella,
filling up the vacuity in the front of the joint between the femur and tibia. In
extension, the tibia and inter-articular cartilages glide forwards upon the femur;
all the ligaments are stretched, with the exception of the ligamentum patellae,
which is relaxed, and admits of considerable lateral movement. The movement
of rotation is permitted when the knee is semi-flexed, rotation outwards being
most extensive.
3. Articulations between the Tibia and Fibula.
The articulations between the tibia and fibula are effected by ligaments which
connect both extremities, as well as the centre of these bones. They may, conse-
quently, be subdivided into three sets. i. The Superior Tibio-Fibular articula-
tion. 2. The Middle Tibio-Fibular articulation. 3. The Inferior Tibio-Fibular
articulation.
I. Superior Tibio-Fibular Articulation.
This articulation is an arthrodial joint. The contiguous surfaces of the bones
present two flat oval surfaces covered with cartilage, and connected together by
the following ligaments.
Anterior Superior Tibio-Fibular.
Posterior Superior Tibio-Fibular.
Synovial Membrane.
The Anterior Superior Ligament (fig. 124) consists of two or three broad and
flat bands, which pass obliquely upwards and inwards, from the head of the fibula
to the outer tuberosity of the tibia.
TIBIO-FIBULAR.
177
The Posterior Superior Ligament is a single thick and broad band, which
passes from the back part of the head of the fibula to the back j^art of the outer
tuberosity of the tibia. It is covered in by the tendon of the Popliteus muscle.
There is a distinct Synovial Membrane in this articulation. Occasionally the
synovial membrane of the knee-joint is continuous with it at its upper and back
part.
2. Middle Tibio-Fibular Articulation.
The interval between the tibia and fibula is filled up by an interosseous mem-
brane, which extends between the contiguous margins of the two bones. It
consists of a thin aponeurotic lamina composed of oblique fibres, which pass
between the interosseous ridges on the tibia and fibula. It is broader above than
below, and presents at its upper part a large oval aperture for the passage of the
anterior tibial artery forwards to the anterior aspect of the leg; and at its lower
third, another opening, for the passage of the anterior peroneal vessels. It is
continuous below with the inferior interosseous ligament; and is perforated in
numerous parts for the passage of small vessels. By its anterior surface it is in
relation with the Tibialis anticus, Extensor longus digitorum. Extensor proprius
pollicis, Peroneus tertius, and the anterior tibial vessels and nerve; behind, with
the Tibialis posticus and Flexor longus pollicis muscles.
3. Inferior Tibio-Fibular Articulation.
This articulation, continuous with that of the ankle-joint, is formed by the
convex surface at the lower end of the inner side of the fibula, being received
into a concave surface on the outer side of the tibia. These surfaces, below, to
the extent of about two lines, are smooth and covered with cartilage, which is
continuous with that of the ankle-joint. Its ligaments are —
Inferior Interosseous. Posterior Inferior Tibio-fibular.
Anterior Inferior Tibio-fibular. Transverse.
The Inferior Interosseous Ligament consists of numerous short, strong fibrous
bands, which pass between the contiguous rough surfaces of the tibia and fibula,
constituting the chief bond of union between these bones. It is continuous, above,
with the interosseous membrane.
The Anterior Inferior Ligament {^g.12']^ is a flat triangular band of fibres,
broader below than above, which extends obliquely downwards and outwards be-
tween the adjacent margins of the tibia and fibula on the front aspect of the
articulation. It is in relation, in front, with the Peroneus tertius, the aponeurosis
of the leg, and the integument; behind, with the inferior interosseous ligament,
and lies in contact with the cartilage covering the astragalus.
The Posterior Inferior Ligament, smaller than the preceding, is disposed in
a similar manner on the posterior surface of the articulation.
The Transverse Ligament is a long narrow band of ligamentous fibres, con-
tinuous with the preceding, passing transversely across the back of the joint,
from the external malleolus to the tibia, a short distance from its malleolar process.
The three preceding ligaments project somewhat below the margins of the bones,
and form part of the articulating surface for the ankle-joint.
The Synovial Membrane lining the articular surfaces is derived from that of
the ankle-joint.
Actions. The movement permitted in these articulations is limited to a very
slight gliding of the articular surfaces upon one another.
N
178
ARTICULATIONS.
4. Ankle Joint.
The Ankle is a ginglymoid or hinge joint. The bones entering into its forma-
tion are the lower extremity of the tibia and its malleohis, and the malleolus of
the fibula, above, which, united, form an arch, in which is received the upper
convex surface of the astragalus and its two lateral facets. These surfaces are
covered with cartilage, lined by synovial membrane, and connected together by
the following ligaments:
Anterior. Internal Lateral.
External Lateral.
The Anterior Ligament (fig, 126) is a broad, thin, membranous layer, attached,
above, to the margin of the articular surface of the tibia; below, to the margin of
the astragalus, in front of its articular surface. It is in relation, in front, with
126. — Ankle-joint: Tarsal and Tarso-Metatarsal Articulations.
Eight Side.
Internal View.
TARSO-METATARSAl.
ARTIC
TARSAL ARTlC"f
the extensor tendons of the toes, the tendons of the Tibialis anticus and Peroneus
tertius, and the anterior tibial vessels and nerve; posteriorly, it lies in contact
with the synovial membrane.
The Internal Lateral or Deltoid Ligament consists of two layers, superficial
and deep. The superficial layer is a strong, flat, triangular band, attached, above,
to the apex and anterior and posterior borders of the inner malleolus. The most
anterior fibres pass forwards to be inserted into the scaphoid; the middle descend
almost perpendicularly to be inserted into the os calcis; and the posterior fibres
pass backwards and outwards to be attached to the inner side of the astragalus.
The deeper layer consists of a short, thick, and strong fasciculus, which passes
from the apex of the malleolus to the inner surface of the astragalus, below the
articular surface. This ligament is covered in by the tendons of the Tibialis
posticus and Flexor longus digitorum muscles.
ANKLE-JOINT.
179
The External Lateral Ligament (fig. 127) consists of three fasciculi, taking
different directions, and separated by distinct intervals.
The anterior fasciculus, the shortest of the three, passes from the anterior
margin of the summit of the external malleolus, downwards and forwards, to the
astragalus, in front of its external articular facet.
Tlhe, posterior fasciculus, the most deeply seated, passes from the depression at
the inner and back part of the external malleolus to the astragalus, behind its
external malleolar facet. Its fibres are directed obliquely downwards and in-
wards.
The middle fasciculus, the longest of the three, is a narrow rounded cord, pass-
ing from the apex of the external malleolus downwards and slightly backwards to
the middle of the outer side of the os calcis. It is covered by the tendons of the
Peroneus longus and brevis. There is no posterior ligament, its place being sup-
plied by the transverse ligament of the tibia and fibula.
The Synovial Membrane invests the cartilaginous surfaces of the tibia and
127. — ^Ankle- Joint : Tarsal and Tarso-Metatarsal Articulations.
Right Side.
External View.
INFERIOR TIBIO-FIEULAFI
ARTJCS
ANKLE-40INT
TflRSAL ARTIC"?
TARSO-METATAFtSAL ARTICB?
fibula, and sends a duplicature upwards between their lower extremities; it is
then reflected on the inner surface of the ligaments surrounding the joint, and
covers the upper surface of the astragalus and its two lateral facets below.
Relations. The tendons, vessels, and nerves in connection with this joint are,
in front, from within outwards, the Tibialis anticus, Extensor proprius pollicis,
anterior tibial vessels, anterior tibial nerve. Extensor communis digitorum, and
Peroneus tertius; behind, from within outwards. Tibialis posticus, Flexor longus
digitorum, posterior tibial vessels, posterior tibial nerve, Flexor longus pollicis,
and, in the groove behind the external malleolus, the tendons of the Peroneus
longiis and brevis.
The Arteries supplying the joint are derived from the malleolar branches of the
anterior tibial and peroneal.
The Nerves are derived from the anterior tibial. .
Actions. The movements of this joint are limited to" flexion and extension,
There is no lateral motion.
N 2
i8o ARTICULATIONS.
5. Articulations of the Tarsus.
These articulations may be subdivided into three sets: I. The articulation of
the first row of tarsal bones. 2. The articulation of the second row of tarsal
bones. 3. The articulation of the two rows with each other.
I. Articulation of the First Row of Tarsal Bones.
The articulation between the astragalus and os calcis is an arthrodial joint,
connected together by three ligaments.
External Calcaneo-Astragaloid. Interosseous.
Posterior Calcaneo-Astragaloid. Two Synovial Membranes.
The External Calcaneo-Astragaloid Ligament (fig. 127) is a short, strong fasci-
culus, passing from the outer surface of the astragalus, immediately beneath its
external malleolar facet, to the outer edge of the os calcis. It is placed in front
of the middle fasciculus of the external lateral ligament of the ankle-joint, with
the fibres of which it is parallel.
The Posterior Calcaneo-Astragaloid Ligament (fig. 126) connects the posterior
extremity of the astragalus with the upper contiguous surface of the os calcis; it
is a short narrow band, the fibres of which are directed obliquely backwards and
inwards.
The Interosseous Ligament forms the chief bond of union between these bones.
It consists of numerous vertical and oblique fibres, attached by one extremity to
the groove between the articulating surfaces of, the astragalus, by the other, to a
corresponding depression on the upper surface of the os calcis. It is very thick
and strong, being at least an inch in breadth from side to side, and serves to unite
the OS calcis and astragalus solidly together.
The Synovial Membranes (fig. I2g) are two in number; one for the posterior
calcaneo-astragaloid articulation, a second for the anterior calcaneo-astragaloid
joint. The latter synovial membrane is continued forwards between the con-
tiguous surfaces of the astragalus and scaphoid bones.
2. Articulations of the Second Row of Tarsal Bones.
The articulations between the scaphoid, cuboid, and three cuneiform are effected
by the following ligaments.
Dorsal. Plantar.
Interosseous.
The Dorsal Ligaments are small bands of parallel fibres, which pass from each
bone to the neighbouring bones with which it articulates.
The Plantar Ligaments have the same arrangement on the plantar surface.
The Interosseous Ligaments are four in number. They consist of strong
transverse fibres, which pass between the rough non-articular surfaces of adjoin-
ing bones. There is one between the sides of the scaphoid and cuboid, a second
between the internal and middle cuneiform bones, a third between the middle and
external cuneiform, and a fourth between the external cuneiform and cuboid.
The scaphoid and cuboid, when in contact, present each a small articulating facet,
covered with cartilage, and lined either by a separate synovial membrane, or by
an offset from the common tarsal synovial membrane.
3. Articulations of the Two Rows of the Tarsus with each other.
These articulations consist of ligaments that may be conveniently divided into
OF THE TARSUS.
i8i
three sets. i. The articulation of the os calcis with the cuboid. 2. Tlic os
calcis with the scaphoid. 3. The astragalus with the scaphoid.
I. The ligaments connecting the os calcis with the cuboid are four in number.
Dorsal.
Plantar,
( Superior Calcaneo-Cuboid.
( Internal Calcaneo-Cuboid (Interosseous),
j Long Calcaneo-Cuboid.
" \ Short Calcaneo-Cuboid.
128. — Ligaments of Plantar Surface of the
Foot.
Synovial Membrane.
The Superior Calcaneo-Cuboid Ligament (fig. 1 27) is a thin and narrow
fasciculus, which passes between the contiguous surfaces of the os calcis and
cuboid, on the dorsal surface of the joint.
The Internal Calcaneo-Cuboid {Interosseous) Ligament (Q.g. 127) is a short, but
thick and strong, band of fibres, arising from the os calcis, in the deep groove which
intervenes between it and the astragalus; being closely blended, at its origin,
with the superior calcaneo-scaphoid ligament. It is inserted into the inner side
of the cuboid bone. This ligament forms one of the chief bonds of union between
the first and second row of the tarsus.
The Long Calcaneo-Cuboid (fig. 128), the most superficial of the two plantar
ligaments, is the longest of all the liga-
ments of the tarsus, being attached pos-
teriorly to the under surface of the os
calcis, as far forwards as the anterior
tubercle, and passing horizontally for-
wards to the tuberosity on the under
surface of the cuboid bone, the more
superficial fibres being continued for-
wards to the bases of the second, third,
and fourth metatarsal bones. This liga-
ment crosses the groove on the under
surface of the cuboid bone, converting it
into a canal for the passage of the ten-
don of the Peroneus longus.
The Short Calcaneo- Cuboid lies nearer
to the bones than the preceding, from
which it is separated by a little areolar
adipose tissue. It is exceedingly broad,
and about an inch in length ; passing
from the tuberosity at the fore part of
the under surface of the os calcis, to the
inferior surface of the cuboid bone be-
hind the peroneal groove. A synovial
membrane lines the contiguous svirfaces
of the bones, and is reflected upon the
i ligaments connecting them.
2. The ligaments connecting the os
[calcis with the scaphoid are two in num-
1 ber.
Superior Calcaneo- Scaphoid.
Inferior Calcaneo- Scaphoid.
. Synovial Membrane.
The Superior Calcaneo - ScapJtoid
.arises, (fig. I27)as already mentioned, with
fthe internal calcaneo-cuboid in the deep
groove between the astragalus and os calcis, it "passes^ forward from the inner
side of the anterior extremity of the os calcis to the outer side of the scaphoid
I«2
ARTICULATIONS.
bone. These two ligaments resemble the letter Y, being blended together behind,
but separated in front.
The Inferior Calcaneo- Scaphoid {^g. 128) is by far the largest and strongest of
the two ligaments of this articulation; it is a broad and thick band of ligamentous
fibres, which passes forwards and inwards from the anterior and inner extremity
of the OS calcis, to the under surface of the scaphoid bone. This ligament not only
serves to connect the os calcis and scaphoid, but supports the head of the astra-
galus, forming part of the articular cavity in which it is received. Its upper
surface is lined by the synovial membrane continued from the anterior calcaneo-
astragaloid articulation. Its under surface is in contact with the tendon of the
Tibialis posticus muscle.
3. The articulation between the astragalus and scaphoid is an enarthrodial
joint; the rounded head of the astragalus being received into the concavity formed
by the posterior surface of the scaphoid, the anterior articulating surface of the
calcaneum, and the upper surface of the calcaneo- scaphoid ligament, which fills up
the triangular interval between these bones. The only ligament of this joint is
the superior astragalo-scaphoid, a broad band of ligamentous fibres, which passes
obliquely forwards from the neck of the astralagus, to the superior surface of the
scaphoid bone. It is thin and weak in texture, and covered by the Extensor
tendons. The inferior calcaneo-scaphoid supplies the place of an inferior liga-
ment.
The Synovial Membrane which lines this joint is continued forwards from the
anterior calcaneo-astragaloid articulation. This articulation permits of considerable
mobility; but its feebleness is such as to occasionally allow of dislocation of the
astragalus.
The Synovial Membranes (fig. 129) found in -the articulations of the tarsus are
129. — Oblique Section of the Articulations of the Tarsus and Metatarsus.
Shewing the Six Synovial Membranes.
four in number: one for the posterior calcaneo-astragaloid articulation; a second
for the anterior calcaneo-astragaloid and astragalo-scaphoid articulations; a third
for the calcaneo-cuboid articulation; and &. fourth for the articulations between
the scaphoid and the three cuneiform, the three cuneiform with each other, the
external cuneiform with the cuboid, and the middle and external cuneiform with
the bases of the second and third metatarsal bones. The prolongation which lines
the metatarsal bones, passes forwards between the external and middle cuneiform
bones. A small synovial membrane is sometimes found between the contiguous
surfaces of the scaphoid and cuboid bones.
Actions. The movements permitted between the bones of the first row, the
TARSO-METATARSAL. 183
astragalus, and os calcis, are limited to a gliding upon each other from before
backwards, and from side to side. The gliding movement which takes place
between the bones of the second row is very slight, the articulation between the
scaphoid and cuneiform bones being more moveable than those of the cuneiform
with each other and with the cuboid. The movement which takes place between
the two rows is more extensive, and consists in a sort of rotation, by means ot
which the sole of the foot may be slightly flexed, and extended, or carried inwards
and outwards.
6. Tarso-Metataksal Articulations.
These are arthrodial joints. The bones entering into their formation are the
internal, middle, external cuneiform, and cuboid, which articulate with the meta-
tarsal bones of the five toes. The metatarsal bone of the first toe articulates with
the internal cuneiform; that of the second is deeply wedged in between the in-
ternal and external cuneiform, resting against the middle cuneiform, and being the
most strongly articulated of all the metatarsal bones; the third metatarsal articu-
lates with the extremity of the external cuneiform; the fourth with the cuboid
and external cuneiform; and the fifth with the cuboid. These various articular
surfaces are covered with cartilage, lined by synovial membrane, and connected
together by the following ligaments.
Dorsal. Plantar.
Interosseous.
The Dorsal Ligaments consist of strong, flat, fibrous bands, which connect the
tarsal with the metatarsal bones. The first metatarsal is connected to the inter-
nal cuneiform by a single broad, thin, fibrous band; the second has three dorsal
ligaments, one from each cuneiform bone; the third has one from the external
cuneiform; and the fourth and fifth have one each from the cuboid.
The Plantar Ligaments consist of strong fibrous bands connecting the tarsal
and metatarsal bones, but disposed with less regularity than on the dorsal surface.
Those for the first and second metatarsal are the most strongly marked; the
second and third receive strong fibrous bands, which pass obliquely across from
the internal cuneiform; the plantar ligaments of the fourth and fifth consist of a
few scanty fibres derived from the cuboid.
The Interosseous Ligaments are three in number: internal, middle, and exter-
nal. The internal one passes from the outer extremity of the internal cuneiform,
to the adjacent angle of the second metatarsal. The middle one, less strong than
the preceding, connects the external cuneiform with the adjacent angle of the
second metatarsal. The external interosseous ligament connects the outer angle
of the external cuneiform with the adjacent side of the third metatarsal.
The Synovial Membranes of these articulations are three in number: one for the
metatarsal bone of the great toe, with the internal cuneiform: one for the second
and third metatarsal bones, with the middle and external cuneiform; this is con-
tinuous with the great tarsal synovial membrane: and one for the fourth and fifth
metatarsal bones with the cuboid. The synovial membranes of the tarsus and
metatarsus are thus seen to be six in number (fig. 129).
Articulations of the Metatarsal Bones with each other.
At their tarsal extremities, the metatarsal bones are connected together by dorsal,
plantar, and interosseous ligaments. The dorsal and plantar ligaments pass from
one metatarsal bone to another. The interosseous ligaments lie deeply between the
rough non-articular portions of their lateral surfaces. The articular surfaces are
covered by synovial membrane, continued forwards from their respective tarsal
joints. At their digital extremities, they are connected to each other by the trans-
verse metatarsal ligament, which holds them loosely together. This ligament,
which is analogous to the same structure in the hand, connects the great toe
v/ith the rest of the metatarsal bones, which in this respect difiers from the same
structure in the hand.
1 84 ARTICULATIONS.
Actions. The movement permitted in the tarsal ends of the metatarsal bones is
limited to a slight gliding of the articular surfaces upon one another; considerable
motion, however, takes place in their digital extremities.
Metatarso-Phalangeal Articulations.
The heads of the metatarsal bones are connected with the concave articular
surfaces of the first phalanges by the following ligaments :
Anterior or Plantar. Two Lateral.
Synovial Membrane.
They are arranged precisely similar to the corresponding parts in the hand.
The expansion of the extensor tendon supplies the place of a posterior ligament.
Actions. The movements permitted in the metatarso-phalangeal articulations are
flexion, extension, abduction, and adduction.
Articulation of the Phalanges.
The ligaments of these articulations are similar to those found in the hand; each
pair of phalanges being connected by an anterior or plantar and two lateral liga-
ments, and their articular surfaces lined by synovial membrane. Their actions
are also similar.
I
The Muscles and Fasciae.
THE Muscles and Fasciae are descx-ibed conjointly, in oi-der that the student may
considei' the arrangement of the latter in his dissection of the former. It is
rare for the student of anatomy in this country to have the opportunity of dissect-
ing the fascite separately; and it is from this reason, as well as from the close
connexion that exists between the muscles and their investing aponeuroses, that
they are considered together. Some general observations are first made on the
anatomy of the muscles and fasciae, the special description being given in con-
nexion with the different regions.
The Muscles are the active organs of locomotion. They are formed of bundles
of reddish fibres, consisting chemically of fibrine, and endowed with the property
of contractility.
Muscle is of a deep red colour, the intensity of which varies considerably with
the age and health of the individual. It is composed of bundles of parallel fibres,
placed side by side, and connected together by a delicate web of areolar tissue.
Each fasciculus consists of numerous smaller bundles, and these of single fibres,
which, from their minute size and comparatively isolated appearance, have been
called ultimate fibres. Two kinds of ultimate muscular fibre are found in the
animal body, viz., that of voluntary or animal life, and that of involuntary or
organic life. The ultimate fibre of animal life is capable of being either excited
or controlled by the efforts of the will, and is characterised, on microscopic exami-
nation, by its size, its uniform calibre, and the presence of minute transverse bars,
which are situated at short and i-egular distances throughout its whole extent. Of
such is composed the muscular tissue of the trunk and limbs; the fibres of the
heart, and some of those of the oesophagus: the muscles of the internal ear, and
those of the urethra, present a similar structure, although they are not capable of
being acted upon by the will. Involuntary muscular fibre is entirely withdrawn
from the influence of volition, and is characterised, on microscopic examination, by
the ultimate fibrils being homogeneous in structure, of smaller size than those of
animal life, flattened, and unstriped; of such the muscles of the digestive canal,
the bladder, and uterus are composed.
Each muscle is invested externally by a thin cellular layer, forming what is
called its sheath, which not only covers its outer surface, but penetrates into its
interior in the intervals between the fasciculi, surrounding these, and serving as a
bond of connection between them.
The voluntary muscular fibres terminate at either extremity in fibrous tissue,
the separate fibrillse of which being, in some cases, aggregated together, form a
rounded or flattened fibrous cord or tendon; in the flat muscles, the separate fibres
are arranged in flattened membranous laminae, termed aponeuroses; and it is in
one or other of these forms, that nearly every muscle is attached to the pai't which
it is destined to move.
The involuntary muscular fibres, on the contrary, form a dense interlacement,
crossing each other at various angles, forming a layer of variable thickness, which
usually circumscribes the wall of some cavity, which, by its contraction, it
constricts.
Muscles vary considerably in their form. In the limbs, they are of considerable
length, especially the more superficial ones, the deep ones being generally broad ;
they, surround the bones, and form an important protection to the various joints.
In the trunk, they are broad, flattened, and expanded, forming the parietes of the
cavities which they enclose; hence the reason of the terms, long, broad, short, etc.,
I used in the description of a muscle.
There is considerable variation in the arrangement of the fibres of certain
: muscles, in relation to the tendon to which they are attached. In some, the fibres
i86 MUSCLES AND FASCIA.
are arranged longitudinally, and terminate at either end in a narrow tendon, so
that the muscle is broad at the centre, and narrowed at either extremity: such a
muscle is said to he fusiform in shape, as the Rectus femoris. If the fibres con-
verge, like the plumes of a pen, to one side of a tendon, which runs the entire
length of the muscle, it is said to be penniform, as the Peronei; or, if they converge
to both sides of a tendon, they are called bipenniform, as the Rectus femoris; if
they converge from a broad surface to a narrow tendinous point, they are then
said to be radiated, as the Temporal and Glutei muscles.
Their size presents considerable variation: the Gastrocnemius forms the chief
bulk of the back of the leg, and the fibres of the Sartorius are nearly two feet in
length, whilst the Stapedius, a small muscle of the internal ear, weighs about a
grain, and its fibres are not more than two lines in length. In each case, how-
ever, they are admirably adapted to execute the^ various movements they are
required to perform.
The names applied to the various muscles have been derived: i,from their situ-
ation, as the Tibialis, Radialis, Ulnaris, Peroneus; 2, from their direction, as the
Rectus abdominis, Obliqui capitis, Transversalis; 3, from their uses, as Flexors,
Extensors, Abductors, etc. ; 4, from their shape, as the Deltoid, Trapezius, Rhom-
boideus; 5, from the number of their divisions, as the Biceps (from having two
heads), the Triceps (from having three heads) ; 6, from their points of attachment,
as the Sterno-cleido-mastoid, Sterno-hyoid, Sterno-thyroid.
In the description of a muscle, the term origin is meant to imply its more fixed
or central attachment; and the tei'm insertion, the moveable point upon which
the force of the muscle is directed: this holds true, however, for only a very small
number of muscles, such as those of the face, which are attached by one extremity
to the bone, and by the other to the moveable integument; in the greater number,
the muscle can be made to act from either extremity.
In the dissection of the muscles, the student should pay especial attention to
the exact origin, insertion, and actions of each, and its more important relations
with surrounding parts. An accurate knowledge of the points of attachment of
the muscles is of great importance in the determination of their action. By
a knowledge of the action of the muscles, the surgeon is able at once to explain
the causes of displacement in the various forms of fracture, or the causes which
produce distortion in various forms of deformities, and, consequently, to adopt
appropriate treatment in each case. The relations, also, of some of the muscles
especially those in immediate apposition with the larger blood-vessels; and the
surface-markings they produce should be especially remembered, as they form
most useful guides to the surgeon in the application of a ligature to these vessels.
The Fascias (^fascia, a bandage) are fibro-areolar or aponeurotic laminae, of vari-
able thickness and strength, found in all regions of the body, investing the softer
and more delicate organs. The fasciae have been subdivided, from the structure
which they present, into two groups, fibro-areolar or superficial fasciae, and aponeu-
rotic or deep fascia.
The fibro-areolar fascia is found immediately beneath the integument over
almost the entire surface of the body, and is generally known as the superficial
fascia. It connects the skin with the deep or aponeurotic fascia, and consists of
fibro-areolar tissue, containing in its meshes pellicles of fat in varying quantity.
In the eyelids and scrotum, where adipose tissue is never deposited, this tissue is
very liable to serous infiltration. This fascia varies in thickness in difierent parts
of the body: in the groin it is so thick as to be capable of being subdivided into
several laminae, but in the palms of the hands it is of extreme thinness, and inti-
mately adherent to the integument. The superficial fascia is capable of separation
into two or more layers, between which are found the superficial vessels and nerves,
and superficial lymphatic glands; as the superficial epigastric vessels in the ab-
dominal region, the radial and ulnar veins in the forearm, the saphenous veins
in the leg and thigh, as well as in certain situations cutaneous muscles, as the
Platysma myoides in the neck, Orbicularis palpebrarum around the eyelids. It is
GENERAL ANATOMY. 187
most distinct at the lower part of the abdomen, the scrotum, perinasum, and in the
extremities; is very thin in those regions where muscular fibres are inserted into
the integument, as on the side of the neck, the face, and around the margin of the
anus, and almost entirely wanting in the palms of the hands and soles of the feet,
where the integument is adherent to the subjacent aponeurosis. The superficial
fascia connects the skin to the subjacent parts, serves as a soft nidus, for the pas-
sage of vessels and nerves to the integuments, and retains the warmth of the body
from the adipose tissue contained in its areolee, being a bad conductor of caloric.
The aponeurotic or deep fascia is a dense inelastic and unyielding fibrous
membrane, forming sheaths for the muscles, and affording them broad surfaces for
attachment, it consists of shining tendinous fibres, placed parallel with one another,
and connected together by other fibres disposed in a reticular manner. It is usu-
ally exposed on the removal of the superficial fascia, forming a strong investment,
which not only binds down collectively the muscles in each region, but gives a
separate sheath to each, as well as to the vessels and nerves. The fasciae are
thick in unprotected situations, as on the outer side of a limb, and thinner on
the inner side. By Bichat, aponeurotic fasciae were divided into two classes,
aponeuroses of insertion, and aponeuroses of investment.
The aponeuroses of insertion serve for the insertion of muscles. Some of these
are formed by the expansion of a tendon into an aponeurosis, as, for instance, the
tendon of the Sartorius; others do not originate in tendons, as the aponeuroses of
the abdominal muscles.
The aponeuroses of investment form a sheath for the entire limb, as well as
for each individual muscle. Many aponeuroses, however, serve both for invest-
ment and insertion. Thus the deep fascia on the front of the leg gives
attachment to the muscles in this region; and the aponeurosis of insertion given off
from the tendon of the Biceps is continuous with the investing fascia of the fore-
arm, and gives origin to the muscles in this region. The deep fasciae assist the
muscles in their action, by the degree of tension and pressure they make upon their
surface; and in certain situations this is increased and regulated by muscular
action, as, for instance, by the Tensor vaginae femoris and Gluteus maximus in
the thigh, by the Biceps in the leg, and Palmaris longus in the hand. In the
limbs, the fasciae not only invest the entire limb, but give off septa, which sepa-
rate the various muscles, and are attached beneath to the periosteum; these pro-
longations of fasciae are usually spoken of as intermuscular septa.
The Muscles and Fasciae may be arranged, according to the general division of
the body, into, i. Those of the head, face, and neck. 2. Those of the trunk.
3. Those of the upper extremity. 4. Those of the lower extremity.
MUSCLES AND FASCIA OF THE HEAD AND FACE.
The Muscles of the Head and Face consist of ten groups, arranged according
to the region in which they are situated.
1. Cranial Region. 6. Superior Maxillary Region.
2. Auricular Region. 7. Inferior Maxillary Region.
3. Palpebral Region. 8. Inter-Maxillary Region.
4. Orbital Region. 9. Temporo-Maxillary Region.
5. Nasal Region. lO. Pterygo-Maxillary Region.
The Muscles contained in each of these groups are the following.
I. Epicranial Region. 3. Palpebral Region.
Occipito-frontalis. Orbicularis palpebrarum.
r. A • 1 D • Corrugator supercilii.
2. Auricular Keqion. m •
. ^^ ,, lensor tarsi.
Attoliens aurem.
Attrahens aurem. ' 4- Orbital Region.
Retrahens aurem. Levator palpebrae.
MUSCLES AND FASCIA.
Rectus superior.
Rectus inferior.
Rectus internus.
Rectus externus.
Obliquus superior.
Obliquus inferior.
5. Nasal Region.
Pyramidalis nasi.
Levator labii superioris al^que nasi.
Levator proprius alee nasi posterior.
Levator proprius alfB nasi anterior.
Compressor nasi.
Compressor narium minor.
Depressor alae nasi,
6. Superior Maxillary Region.
Levator labii superioris proprius.
Levator anguli oris.
Zygomaticus major.
Zygomaticus minor.
7. Inferior Maxillary Region.
Levator labii inferioris.
Depi'essor labii inferioris.
Depressor anguli oris.
8. Inter-Maxillary Region.
Buccinator.
Risorius.
Orbicularis oris.
9. T^mporo- Maxillary Region.
Masseter.
Temporal.
10. Ptery go- Maxillary Region.
Pterygoideus externus.
Pterygoideus internus.
I. Epickanial Region — Occipito-Frontalis.
Dissectioni^g. 130). The head being staved, and a block placed beneath the back of the
neck, make a vertical incision through the skin from before backwards, commencing at the root
of the nose in front, and terminating behind at the occipital protuberance ; make a second
incision in a horizontal direction along the forehead and around the side of the head, from
130. — Dissection of the Head, Face, and Neck.
-/ UlssectioTiofscMj'
S.S^of AURICULAR REGION
4^.5. 6. of FACE
J. 8. of NECK
the anterior to the posterior extremity of the preceding. Eaise the skin in front from the
subjacent muscle from below upwards ; this must be done with extreme care, on account
of their intimate union. The tendon of this muscle is best avoided by removing the in-
tegument from the outer surface of the vessels and nerves which lie between the two.
The superficial fascia in the epicranial region is a firm, dense layer, intimately
adherent to the integument, and to the Occipito-frontalis and its tendinous aponeu-
rosis; it is continuous, behind, with the superficial fascia at the back pai*t of the
neck; and, laterally, is continued over the temporal aponeurosis: it contains be-
tween its layers the small muscles of the auricle, and the superficial temporal
vessels and nerves.
The Occipito-frontalis (fig. 131) is a broad musculo-fibrous layer, which covers
over the whole of one side of the vertex of the skull, from the occiput to the eye-
OCCIPITO-FRONTALIS.
i8g
brow. It consists of two muscular bellies, separated by an intervening tendinous
aponeurosis. The occipital portion, thin, quadrilateral in form, and about an inch
and a half in length, arises from the outer two-thirds of the superior curved line
of the occijiital bone, and from the mastoid portion of the temporal. Its fibres of
CORRUCATOR
OILATOK NARIS A^
DILATOaNARIS POSTER
131. — Muscles of the Head, Face, and Neck.
origin are tendinous, but they soon become muscular, and ascend in a parallel
direction to terminate in the tendinous aponeurosis. The frontal portion is thin,
of a quadrilateral form, and intimately adherent to the skin. It is broader, its
fibres are longer, and their structure more pale than the occipital portion. Its
igo MUSCLES AND FASCIA.
internal fibres are continuous with those of the Pyramidalis nasi. Its middle
fibres become blended with the Corrugator supercilii and Orbicularis: and the
outer fibres are also blended with the latter muscle over the external angular
process. The inner margins of the two frontal portions of the muscle are joined
together for some distance above the root of the nose; but between the occipital
portions there is a considerable but variable interval.
The aponeurosis covers over the whole of the vertex of the skull without any
separation into two lateral parts, and is connected with the occipital and frontal
portions of the muscle. Behind, it is attached, in the interval between the occi-
pital origins, to the occipital protuberance and superior curved lines above the
attachment of the trapezius; in front, it forms a short angular prolongation be-
tween the frontal portions; and on each side, it has connected with it the Attollens
and Attrahens aurem muscles: in this situation it loses its aponeurotic character,
and is continued over the temporal fascia to the zygoma by a layer of laminated
areolar tissue. This aponeurosis is closely connected to the integument by a
dense fibro-cellular tissue, which contains much granular fat, and in which ramify
the numerous vessels and nerves of the integument; it is loosely connected with
the pericranium by a quantity of loose cellular tissue, which allows of a considerable
degree of movement of the integument.
Nerves. The Occipito-frontalis is supplied (frontal portion) by the supra-orbital
and facial nerves; (occipital portion) by the posterior auricular branch of the facial
and the small occipital.
Actions. This muscle raises the eyebrows and the skin over the root of the nose;
at the same time it throws the integument of the forehead into transverse wrinkles,
a predominant expression in the emotions of delight. It also moves the scalp from
before backwards, by bringing alternately into action the occipital and frontal
portions.
Auricular Region (fig. 131).
Attollens Aurem. Attrahens Aurem.
Retrahens Aurem.
These three small muscles are placed immediately beneath the skin around the
external ear. In man, in whom the external ear is almost immoveable, they are
rudimentary. They are the analogues of large and important muscles in some of
the mammalia.
Dissection. This requires considerable care, and should be performed in the following
manner. To expose the Attollens aurem ; draw the pinna or broad part of the ear down-
wards, when a tense band will be felt beneath the skin, passing from the side of the head
to the upper part of the concha; by dividing the skin over the tendon, in a direction from
below upwards, and then reflecting it on each side, the muscle is exposed. To bring into
view the Attrahens aurem, draw the helix backwards by means of a hook, when the muscle
will be made tense, and may be exposed in a similar manner to the preceding. To expose
the Retrahens aurem, draw the pinna forwards, when the muscle being made tense may be
felt beneath the skin, at its insertion into the back part of the concha, and may be exposed
in the same manner as the other muscles.
The Attollens Aurem (superior auriculae), the largest of the three, is thin,
and of a radiated form; it arises from the aponeurosis of the Occipito-frontalis, and
is inserted by a thin, flattened tendon into the upper and anterior part of the concha.
Relations. Externally, with the integument; internally, with the Temporal apo-
neurosis.
The Attrahens Aurem (anterior auriculse), the smallest of the three, is of a
triangular form, very thin in texture, and its fibres pale and indistinct. It arises
from the lateral edge of the aponeurosis of the Occipito-frontalis; its fibres con-
verge to be inserted into the front of the helix.
Relations. Externally, with the skin; internally, with the temporal fascia,
which separates it from the temporal artery and vein.
The Retrahens Aurem (posterior auriculae) consists of two or three fleshy
AURICULAR AND PALPEBRAL REGIONS.
191
fasciculi, which arise from the mastoid portion of the temporal bone by short
aponeurotic fibres. They are inserted into the back part of the concha.
Relations. Externally, with the integument; internally, with the mastoid portion
of the temporal bone.
Nerves. The Attollens aurem is supplied by the small occipital; the Attrahens
aurem, by the facial and auriculo-temporal branch of the inferior maxillary, and
the Retrahens aurem, by the posterior auricular branch of the facial.
Actions. In man these muscles possess very little action; their use is sufficiently
expressed in their names.
Palpebral Region (fig. 131).
Orbicularis Palpebrarum. Levator Palpebrge.
Corrugator Supercilii. Tensor Tarsi.
Dissection (fig. 1 30 — 4). In order to expose the muscles of the face, continue the longitudinal
incision made in the dissection of the Occipito-frontalis, down the median line of the face to
the tip of the nose, and from this point onwards to the upper lip ; another incision should
be carried along the margin of the lip to the angle of the mouth, and transversely across
the face to the angle of the jaw. The integument should also be divided by an incision
made in front of the external ear, from the angle of the jaw, upwards, to the transverse
incision made in exposing the Occipito-frontalis. These incisions include a square-shaped
flap which should be carefully removed in the direction marked in the figure, as the mus-
cles at some points are intimately adherent to the integument.
The Orbicularis Palpebrarum is a sphincter muscle which surrounds the whole
circumference of the orbit and eyelids. It arises from the internal angular process
of the frontal bone, from the nasal process of the superior maxillary in front of
the lachrymal groove, and from the anterior surface and borders of a short tendon,
the Tendo palpebrarum, placed at the inner angle of the orbit. The muscle, thus
arising, forms a broad, thin, and flat plane of elliptical fibres, which cover the eye-
lids, surround the circumference of the orbit, and spread out over the temple, and
downwards on the cheek, becoming blended with the Occipito-frontalis and Corru-
gator supercilii. The palpebral portion (ciliaris) of the Orbicularis is thin and
pale; it arises from the bifurcation of the Tendo palpebrarum, and forms a series
of concentric curves, which are united on the outer side of the eyelids at an acute
angle by a cellular raphe, some being inserted into the external tarsal ligament
and malar bone. The orbicular portion (orbicularis latus) is thicker, of a reddish
colour, its fibres well developed, forming a complete ellipse.
The tendo palpebrarum (oculi) is a short tendon, about two lines in length
and one in breadth, attached to the nasal process of the superior maxillary bone
anterior to the lachrymal groove. Crossing the lachrymal sac, it divides into two
parts, each division being attached to the inner extremity of the corresponding
tarsal cartilage. As the tendon crosses the lachrymal sac, a strong aponeurotic
lamina is given off from its posterior surface, which expands over the sac, and is
attached to the ridge on the lachrymal bone. This is the reflected aponeurosis of
the Tendo palpebrarum.
Relations. By its superficial surface, the orbicular portion is closely adherent to
the integument, more especially over the upper segment of the muscle; the palpe-
bral portion being separated from the skin by loose areolar tissue. By its deep
surface, above, with the Occipito-frontalis and Corrugator supercilii, with which
it is intimately blended, and with the supra-orbital vessels and nerve; below, it
covers the lachrymal sac and the origin of the Levator labii superior! s. Levator
labii superioris alaeque nasi, and the Zygomaticus major and minor muscles.
Internally, it is occasionally blended with the Pyramidalis nasi. Externally, it lies
on the temporal fascia. On the eyelids, it is separated from the conjunctiva by a
fibrous membrane and the tarsal cartilages.
The Corrugator Supercilii is a small, narrow, pyramidal muscle, placed at the
inner extremity of the eyebrow beneath the Occipito-frontalis and Orbicularis
192 MUSCLES AND FASCIiE.
palpebrarum muscles. It arises from the inner extremity of the superciliary ridge;
its fibres pass upwards and outwards, to be inserted into the vmder surface of the
orbicularis, opposite the middle of the orbital arch.
Relations. By its anterior surface, with the Occipito-frontalis and Orbicularis
palpebrarum muscles. By its posterior surface, with the frontal bone and supra-
orbital vessels and nerve.
The Levator PalpebrcB will be described with the muscles of the orbital region.
The Tensor Tarsi is a small thin muscle, about three lines in breadth and six
in length, situated at the inner side of the orbit, beneath the Tendo oculi. It
arises from the crest and adjacent part of the orbital surface of the lachrymal bone,
and passing across the lachrymal sac, divides into two slips, which cover the la-
chrymal canals, and are inserted into the tarsal cartilages near the Puncta lachry-
malia. Its fibres apj)ear to be continuous with those of the palpebral portion of
the Orbicularis; it is occasionally very indistinct.
Nerves. The Orbicularis palpebrarum and Corrugator supercilii are supplied
by the facial and supra-orbital nerves; the Tensor tarsi by the facial.
Actions. The Orbicularis palpebrarum is the sphincter muscle of the eyelids.
The palpebral portion acts involuntarily in closing the lids, and independently of
the orbicular portion, which is subject to the will. When the entire muscle is
brought into action, the integum^ents of the forehead, temple, and cheek are drawn
inwards towards the inner angle of the eye, and the eyelids are firmly closed.
The Levator palpebrse is the direct antagonist of this muscle; it raises the upper
eyelid, and exposes the globe. The Corrugator supercilii draws the eyebrow
downwards and inwards, producing the vertical wrinkles of the forehead. This
muscle may be regarded as the principal agent in the expression of grief. The
Tensor tarsi draws the eyelids and the exti'emities of the lachrymal canals
inwards, and compresses them against the surface of the globe of the eye; thus
p lacing them in the most favourable situation for receiving the tears. It serves,
a Iso, to compress the lachrymal sac.
Orbital Region (fig. 132).
Levator Palpebrse. Rectus Internus.
Rectus Superior. Rectus Externus.
Rectus Inferior. Obliquus Superior.
Obliquus Inferior.
Dissection. To open the cavity of the orbit, the skull-cap and brain should be first
removed ; then saw through the frontal bone at the inner extremity of the supra-orbital
ridge, and externally at its junction with the malar. The thin roof of the orbit should
then be comminuted by a few slight blows with the hammer, and the superciliary portion
of the frontal bone driven forwards by a smart stroke ; but must not be removed. The
several fragments may then be detached, when the periosteum of the orbit will be exposed :
this being removed, together with the fat which fills the cavity of the orbit, the several
muscles of this region can be examined. To facilitate their dissection, the globe of the
eye should be distended ; this may be effected by puncturing the optic nerve near the
eyeball, with a curved needle, and pushing it onwards into the globe. Through this aper-
ture the point of a blow-pipe should be inserted, and a little air forced into the cavity of
the eyeball ; then apply a ligature around the neiwe, so as to prevent the air escaping.
The globe should now be drawn forwards, when the muscles will be put upon the
stretch.
The Levator PalpebrcB is a thin, flat, triangular muscle. It arises from the
under surface of the lesser wing of the sphenoid, immediately above the optic
foramen; and is inserted, by a broad aponeurosis, into the upper border of the
superior tarsal cartilage. At its origin it is narrow and tendinous, but soon
becomes broad and fleshy, and finally terminates in a broad aponeurosis.
Relations. By its upper surface, with the frontal nerve and artery, the peri-
osteum of the orbit; and in front with the inner surface of the broad tarsal liga-
ment. By its under surface, with the Superior rectus; and, in the lid, with the
conjunctiva.
ORBITAL REGION.
193
The Rectus Superior {Attollens), tho tliinnest and narrowest of the four Recti,
arises from tlie upper margin of tlxo optic foramen, beneath the Levator palpebras
and Superior oblique, and from the fibrous slieath of tho optic nerve; and is
132. — Muscles of the Right Orbit.
133. — The relative Position and Attach-
ment of the Muscles of the Left
Eyeball.
Ha^cb reels' ti(p« vlar
inserted, by a tendinous expansion, into the sclerotic coat of the eyeball, about
three or four lines from the margin of the cornea.
Relatio7is. By its upper surface, with the Levator palpebrse. By its under
surface, with the optic nerve, the ophthalmic artery, and nasal nerve; and in
front with the tendon of the Superior oblique and the globe of the eye.
The Inferior and Internal Recti arise by a common tendon (the ligament
of Zinn), which is attached around the circumference of the optic foramen,
except at its upper and outer part. The
External rectus has two heads : the upper
one arises from the outer margin of the
optic foramen, immediately beneath the Su-
perior rectus; the lower head, partly from
the ligament of Zinn, and partly from a
small pointed process of bone on the lower
margin of the sphenoidal fissure. Each
muscle passes forward in the position im-
plied by its name, to be inserted, by a ten-
dinous expansion, into the sclerotic coat of
the eyeball, about three or four lines from
the margin of the cornea. Between the two
heads of the External rectus is a narrow
interval, through which pass the third, nasal
branch of the fifth, and sixth nerves, and the ophthalmic vein. Although nearly
all these muscles present a common origin, and are inserted in a similar manner
into the sclerotic coat, there are certain differences to be observed in them, as re-
gards their length and breadth. The Internal rectus is the broadest, the External
the longest, and the Superior the thinnest and narrowest.
The Superior Oblique is a fusiform muscle, placed at the upper and inner side
of the orbit, internal to the Levator palpebrae. It arises about a line above the
inner margin of the optic foramen, and, passing forwards to the front and mner
side of the orbit, terminates in a rounded tendon, v/hich passes through a fibro-
cartilaginous pulley attached to a depression beneath the internal angular process
■lUa^
194 MUSCLES AND FASCIA.
of the frontal bone, the contiguous surfaces of the tendon and pulley being lined
by a delicate synovial membrane, and enclosed in a thin fibrous investment. The
tendon is then reflected backwards and outwards beneath the Superior rectus to
the outer and posterior part of the globe of the eye, and inserted into the sclerotic
coat between the Superior and External recti muscles, midway between the cornea
and entrance of the optic nerve.
Relations. By its upper surface, with the periosteum covering the roof of the
orbit, and the fourth nerve. By its under surface, with the nasal nerve, and the
upper border of the Internal rectus muscle.
The Inferior Oblique is a thin, narrow muscle, which arises from a depression
in the orbital plate of the superior maxillary bone, immediately external to the
lachrymal groove. Passing outwards and backwards beneath the Inferior rectus,
it terminates in a tendinous expansion, which is inserted into the outer and pos-
terior part of the sclerotic coat of the eyeball.
Relations. By its superior surface, with the globe of the eye, and with the
Inferior rectus. By its under surface, with the periosteum covering the floor of
the orbit, and with the External rectus.
Nerves. The Levator palpebrte. Inferior oblique, and all the recti excepting
the External, are supplied by the third nerve; the Superior oblique by the fourth;
the External rectus by the sixth.
Actions. The Levator palpebrse raises the upper eyelid, and is the direct anta-
gonist of the Orbicularis palpebrarum. The four Recti muscles are attached in
such a manner to the globe of the eye, that, acting singly, they will turn it either
upwards, downwards, inwards, or outwards, as expressed by their names. If any
two Recti act together, they carry the globe of the eye in the diagonal of these
directions, viz. upwards and inwards, upwards and outwards, downwards and
inwards, or downwards and outwards. By some anatomists, these muscles have
been considered the chief agent in adjusting the sight at ditferent distances, by
compressing the globe, and so lengthening its antero-posterior diameter. The
Oblique are the 'rotatory muscles' of the eyeball. The Superior oblique acting
alone, would rotate the globe, so as to carry the pupil outwards and downwards
to the lower and outer side of the orbit; the Inferior oblique rotating the globe
in such a direction, as to carry the pupil upwards and outwards to the upper and
outer angle of the eye.
Surgical Anatomy. The position and exact point of insertion of the tendons of the
Internal and External recti muscles into the globe, should be carefully examined from the
front of the eyeball, as the surgeon is often required to divide one or the other muscle for
the cure of strabismus. In convergent strabismus, which is the most common form of
the disease, the eye is turned inwards, requiring the division of the Internal rectus. In
the divergent form, which is more rare, the eye is turned outwards, the External rectus
being especially implicated. The deformity produced in either case is considerable, and
is easily remedied by division of one or the other muscle. This operation is readily
effected by having the lids well separated by retractors held by an assistant, and the eye-
ball being drawn outwards by a blunt hook ; the conjunctiva shoidd be raised by a pair of
forceps, and divided immediately beneath the lower border of the tendon of the Internal
rectus, a little behind its insertion into the sclerotic ; the submucous areolar tissue is
then divided, and into the small aperture thus made a blimt hook is passed upwards
between the muscle and the globe, and the tendon of the muscle and conjunctiva covering
it divided by a pair of blunt-pointed scissors. Or the tendon may be divided by a sub-
conjunctival incision, one blade of the scissors being passed upwards between the tendon
and the conjunctiva, and the other between the tendon and sclerotic. The student, when
dissecting these muscles, should remove on one side of the subject the conjunctiva from
the front of the eye, in order to see more accurately the position of these tendons, and
on the opposite side the operation may be performed.
NASAL REGION.
195
Nasal Region (fig. 131).
Pyramidalis Nasi.
Levator Labii Superioris Alaeque Nasi.
Levator Proprius Alas Nasi Posterior.
Levator Proprius Ala3 Nasi Anterior.
Compressor Nasi.
Compressor Narium Minor.
Depi'essor Alas Nasi.
The Pyramidalis Nasi is a small pyramidal slip of muscular fibre, prolonged
downwards from the Occipito-frontalis upon the bridge of the nose, where it
becomes tendinous, and blends with the Compressor nasi. As the two muscles
descend, they diverge, leaving an angular interval between them, which is filled
up by cellular tissue.
Relations. By its upper surface, with the skin. By its under surface, with
the frontal and nasal bones. By its outer border, it is connected with the fleshy
fibres of the Orbicularis palpebrarum.
TliQ Levator Labii Superioris Alceque Nasi is a thin triangular muscle, situated
along the side of the nose, and extending between the inner margin of the orbit
and upper lip. It arises by a pointed extremity from the upper part of the nasal pro-
cess of the superior maxillary bone, and passing obliquely downwards and outwards,
divides into two slips, one of which is inserted into the cartilage of the ala of the
nose; the other is prolonged into the upper lip, becoming blended with the Orbi-
cularis and Levator labii proprius.
Relations. In front, with the integument; and with a small part of the Orbicu-
laris palpebrarum above.
Lying upon the superior maxillary bone, beneath this muscle, is a longitudinal
muscular fasciculus about an inch in length. It is attached by one end near the
origin of the Compressor naris, and by the other to the nasal process about an inch
above it; it was described by Albinus as the Musculus 'anomalus,' and by Santorini,
as the 'Rhomboideus.'
The Levator Proprius Alee Nasi Posterior (^dilator 7iaris posterior^ is a small
muscle, which is placed partly beneath the proper elevator of the nose and lip.
It arises from the margin of the nasal notch of the superior maxilla, and fi'om the
sesamoid cartilages, and is inserted into the skin near the margin of the nostril.
The Levator Proprius Alee Nasi Anterior {dilator naris anterior) is a thin,
delicate fasciculus, passing from the cartilage of the ala of the nose to the integu-
ment near its margin. This muscle is situated in front of the preceding.
The Compressor Nasi is a small, thin, triangular muscle, arising by its apex
from the superior maxillary bone, above and a little external to the incisive fossa;
its fibres proceed upwards and inwards, expanding into a thin aponeurosis which
is attached to the fibro-cartilage of the nose, and is continuous on the bridge of
the nose with that of the muscle of the opposite side, and with the aponeurosis of
the pyramidalis nasi.
The Compressor Narium Minor is a small muscle, attached by one end to the
alar cartilage, and by the other to the integument at the end of the nose.
The Depressor Alee Nasi {myrtiformis) is a short, radiated muscle, arising from
the incisive fossa of the superior maxilla; its fibres diverge upwards and outwards,
the upper, or ascending set, being inserted into the septum, and back part of the
ala of the nose; the lower, or descending, into the back part of the upper segment
of the orbicularis.
Nerves. All the muscles of this group are supplied by the facial nerve.
Actions. The Pyramidalis nasi draws down the inner angle of the eyebrow; by
some anatomists it is also considered as an elevator of the ala, and, consequently,
a dilator of the nose. The Levator labii superioi:is alaeque nasi draws upAvards
the upper lip and ala of the nose; its most important action is upon the nose,
which it dilates to a considerable extent. The action of this muscle produces a
o 2
ig6 MUSCLES AND FASCIiE.
marked influence over the countenance, and is the principal agent in the expres-
sion of contempt. The two Levatores alse nasi are the dilators of the pinna of the
nose, and the Compressores nasi appear to act as a dilator of the nose rather than
as a constrictor. The Depressor ala3 nasi is a direct antagonist of the preceding
muscles, drawing the upper lip and ala of the nose downwards, and thereby con-
stricting the aperture of the nares.
Superior Maxillary Region (fig. 131).
Levator Labii Superioris Proprius. Zygomaticus major.
Levator Anguli Oris. Zygomaticus minor.
The Levator Labii Superioris Proprius is a thin muscle of a quadrilateral form.
It arises from the lower margin of the orbit immediately above the infra-orbital
foramen, some of its fibres being attached to the superior maxilla, some to the
malar bone; its fibres converge downwards and inwards to be inserted into the
muscular substance of the upper lip.
Relations. By its superficial surface, with the lower segment of the Orbicu-
laris palpebrarum; below, it is sub-cutaneous. By its deep surface, it conceals the
origin of the Compressor nasi and Levator anguli oris muscles, and the infra-
orbital vessels and nerves, as they escape from the infra-orbital foramen.
The Levator Anguli Oris {musculus caninus) arises by a broad attachment
from the canine fossa, immediately below the infra-orbital foramen; its fibres
incline downwards and a little outwards, to be inserted into the angle of the mouth,
intermingling its fibres with those of the Zygomatici, the Depressor anguli oris,
and the Orbicularis.
Relations. Its superficial surface, is covered 'above by the Levator labii supe-
rioris proprius and the infra-orbital vessels and nerves; below, by the integument.
By its deep surface, it is in relation with the superior maxilla, the Buccinator,
and the mucous membrane.
The Zygomaticus major is a slender cylindrical fasciculus, which arises from
the malar bone, in front of the zygomatic suture, and, descending obliquely down-
wards and inwards, is inserted into the angle of the mouth, where it blends with
the fibres of the Orbicularis and Depressor anguli oris.
Relations. By its superficial surface, occasionally with the Orbicularis palpe-
brarum, above; and below, with the sub-cutaneous adipose tissue. By its deep
surface, with the malar bone, the Masseter and Buccinator muscles.
The Zygomaticus Mi?ior arises from the malar bone, in front of the Zygomati-
cus major, immediately behind the maxillary suture, and, passing downwards and
inwards, is continuous with the outer margin of the Levator labii superioris pro-
prius.
Relations. By its superficial surface, with the integument and the Orbicularis
palpebrarum above. By its deep surface, with the Levator anguli oris.
Nerves. This group of muscles is supplied by the facial nerve.
Actions. The Levator labii superioris proprius is the proper elevator of the
upper lip, carrying it at the same time a little outwards. The Levator anguli
oris raises the angle of the mouth and draws it inwards; whilst the Zygomatici
raise the upper lip, and draw it somewhat outwards, as in laughing.
Inferior Maxillary Region (fig. 131).
Levator Labii Inferioris.
Depressor Labii Inferioris (Quadratus menti).
Depressor Anguli Oris (Triangularis menti).
Dissection. The Muscles in this region may be dissected by making a vertical incision
tlirough the integument from the margin of the lower hp to the chin : a second incision
should then be carried along the margin of the lower jaw as far as the angle, and the integu-
ment carefully removed in the direction shewn in fig. 130.
The Levator L^abii Inferioris {^Levator menti) is to be dissected by everting the
MAXILLARY REGIONS.
197
lower lip and raising the mucous membrane. It is a small conical muscular fasci-
culus, which arises from the incisive fossa, external to the symphysis of the lower
jaw; its fibres expand downwards and forwards, to be inserted into the integu-
ment of the chin.
Relations. On its inner surface, with the buccal mucous membrane; in the
median line, it is blended with the muscle of the opposite side; and on its outer
side, with the Depressor labii inferioris.
The Depressor Labii Inferioris (^Quadratus menti) is a small quadrilateral
muscle, situated at the outer side of the preceding. It arises from the external
oblique line of the lower jaw, between the symphysis and mental foramen, and
passes obliquely upwards and inwards, to be inserted into the integument of the
lower lip, its fibres blending with the Orbicularis, and with those of its fellow of
the opposite side. It is continuous with the fibres of the Platysma at its origin.
Relations. By its superficial surface, with part of the Depressor anguli oris,
and with the integument, to which it is closely connected. By its deep surface,
with the mental vessels and nerves, the mucous membrane of the lower lip, the
labial glands and the Levator labii inferioris, with which it is intimately united.
The Depressor Anguli Oris is a triangular muscle, arising, by its broad base,
from the external oblique line of the lower jaw; its fibres pass upwards, to be
inserted, by a thick and narrow fasciculus, into the angle of the mouth, being con-
tinuous with the Orbicularis, Levator anguli oris, and Zygomaticus major.
Relations. By its superficial surface, with the integument. By its deep sur-
face, with the Depressor labii inferioris, the Platysma, and Buccinator.
Nerves. This group of muscles is supplied by the facial nerve.
Actions. The Levator labii inferioris raises the lower lip, and protrudes it for-
wards; at the same time it wrinkles the integument of the chin. The Depressor
labii inferioris draws the lower lip directly downwards and a little outwards. The
Depressor anguli oris depresses the angle of the mouth, being the great antagonist
to the Levator anguli oris and Zygomaticus major: acting with those muscles, it
will draw the angle of the mouth directly backwards.
Inter-Maxillary Region.
Orbicularis Oris. Buccinator. Risorius.
Dissection. The dissection of these muscles may be considerably faciUtated by filling the
cavity of the mouth with tow, so as to distend the cheeks and lips ; the mouth should
then be closed by a few stitches, and the integument carefully removed from the surface.
The Orbicularis Oris is a sphincter muscle, elliptic in form, composed of con-
centric fibres, which surround the orifice of the mouth. It consists of two thick
semicircular planes of muscular fibre, which surround the oral aperture, and inter-
lace on either side with those of the Buccinator and other muscles inserted into
this part. On the free margin of the lips the muscular fibres are continued unin-
terruptedly from one side to the other, forming a roundish fasciculus of fine pale
fibres closely approximated. To the outer part of each segment some special fibres
are added, by which the lips are connected directly with the maxillary bones
and septum of the nose. The additional fibres for the upper segment consist of
four bands, two of which (Accessorii orbicularis superioris) arise from the alveo-
lar border of the superior maxilla, opposite the incisor teeth, and arching out-
wards on each side, are continuous at the angles of the mouth with the other
muscles inserted into this part.
The two remaining muscular slips, called the Naso-labialis, connect the upper lip
to the septum of the nose: as they descend from the septum, an interval is left
between them, which corresponds to that left by the divergence of the accessory
portions of the Orbicularis above described. It is this interval which forms the
depression seen on the surface of the skin beneath the septum of the nose.
Those for the lower segment (Accessorii orbicularis inferior) arise from the infe-
igS MUSCLES AND FASCIA.
rior maxilla, external to tlie Levator labii inferioris, near the root of the canine
teeth, being separated from each other by a considerable interval; arching out-
vp-ards to the angles of the mouth, they join the Buccinator and the other muscles
attached to this part.
Relations. By its superficial surface, with the integument, to which it is closely
connected. By its deep surface, with the mucous membrane, the labial glands,
and coronary vessels. By its outer circumference, it is blended with the nu-
merous muscles, which converge to the mouth from various parts of the face.
Its inner circumference is free, and covered by mucous membrane.
The Buccinator is a broad, thin muscle, quadrilateral in form, occupying the
interval between the jaws at the side of the face. It arises, above, from the ex-
ternal surface of the alveolar process of the upper jaw, between the first molar
tooth and the tuberosity; below, from the external surface of the alveolar process
of the lower jaw, corresponding to the three last molar teeth; and, behind, from
the anterior border of the pterygo-maxillary ligament. The fibres of this muscle
converge towards the angle of the mouth, where those occupying its centre inter-
siect each other, the inferior fibres being continuous with the upper segment of the
Orbicularis oris; the superior fibres, with the inferior segment; but the upper
and lower fibres continue forward uninterruptedly into the corresponding segment
of the lip.
Relations. By its superficial surface, behind, with a large mass of fat, which
separates it from the ramus of the lower jaw, the Massetei", and a small portion of
the Temporal muscle; anteriorly, Avith the Zygomaticus, Risorius, Levator anguli
oris. Depressor anguli oris, and Stenon's duct, which pierces it opposite the second
molar tooth of the upper jaw; the transverse facial artery and vein lie parallel
with its fibres, and the facial artery and vein cross it from below upwards; it is
also crossed by the branches of the facial and buccal nerves. By its internal sur-
face, with the buccal glands and mucous membrane of the mouth.
The Pterygo-maxillary ligament separates the Buccinator muscle from the
Superior constrictor of the pharynx. It is a tendinous band, attached by one
extremity to the apex of the internal pterygoid plate, and by the other, to the
posterior extremity of the internal oblique line of the lower jaw. Its inner sur-
face corresponds to the cavity of the mouth, and is lined by mucous membrane.
Its outer surface is separated from the ramus of the jaw by a quantity of adipose
tissue. Its posterior border gives attachment to the Superior constrictor of the
pharynx; its anterior border, to the fibres of the Buccinator.
The Risorius {Santorini) consists of a delicate bundle of muscular fibres, which
arises in the fascia over the Masseter muscle, and passing horizontally forwards,
is inserted into the angle of the mouth, joining with the fibres of the Depressor
anguli oris. It is placed superficial to the Platysma, and is broadest at its outer
extremity. This muscle varies much in its size and form.
Nerves. The Orbicularis oris is supplied by the facial, the Buccinator by the
facial and buccal branch of the inferior maxillary nerve.
Actions. The Orbicularis oris is the direct antagonist of all those muscles which
converge to the lips from the various parts of the face, its action producing the
direct closure of the lips; and its forcible action throwing the integument into
wrinkles, on account of the firm connection between the latter and the surface of
the muscle. The Buccinators contract and compress the cheeks, so that, during
the process of mastication, the food is kept under the immediate pressure of the
teeth.
Temporo-Maxillaky Region (fig. 134).
Masseter. Temporal.
The Masseter muscle has been already exposed by the removal of the integu-
ment from the side of the face (fig. 131).
The Blasseter is a short thick muscle, somewhat quadrilateral in form, consisting
TEMPORO-MAXILLARY REGION.
199
of two portions, superficial and deep. The superficial portion, the largest part of
the muscle, arises by a thick tendinous aponeurosis from the malar process of the
superior maxilla, and from the anterior two-thirds of the lower border of the zy-
gomatic arch: its fibres pass downwards and backwards, to be inserted into the
lower half of the ramus and angle of the lower jaw. The deep portion is much
smaller, more muscular in texture, and the direction of its fibres is forwards; it
arises from the posterior third of the lower border and whole of the inner surface
of the zygomatic arch and is inserted into the upper half of the ramus and coro-
noid process of the jaw. The deep portion of the muscle is partly concealed, in
front, by the superficial portion; behind, it is covered by the parotid gland. The
fibres of the two portions are united at their insertion.
Relations. By its superficial surface, with the integument; above, with the
Orbicularis palpebrarum and Zygomaticus major; and has passing across it trans-
versely, Stenon's duct, the branches of the facial nerve, and the transverse facial
artery. By its deep surface, with the ramus of the jaw, the Temporal muscle,
and the Buccinator, from which it is separated by a mass of fat. Its posterior
margin is covered by the parotid gland. Its anterior margin is in relation, below,
with the facial artery.
At this stage of the dissection, the temporal fascia is seen covering in the Tem-
poral muscle. It is a strong aponeurotic investment, affording attachment, by its
inner surface, to the superficial fibres of this muscle. Above, it is a single uniform
layer, attached to the entire extent of the temporal ridge; but below, where it is
attached to the zygoma, it consists of two layers, one of which is inserted into
the outer, and the other to the inner border of the zygomatic arch. A small
quantity of fat, and the orbital branch of the temporal artery, are contained be-
tween these. It is covered, on its outer surface, by the aponeurosis of the
Occipito frontalis, the Orbicularis palpebrarum, and Attollens and Attrahens aurem
muscles; the temporal artery and vein, and ascending branches of the temporal
nerves, cross it from below upwards.
[ 34. — The Temporal Muscle, the Zygoma and Masseter having been removed.
Dissection. In order to expose the Temporal muscle, this fascia should be removed : this
may be eflfected by separating it at its attachment along the upper border of the zygoma,
and dissecting it upwards from the surface of the muscle. The zygomatic arch should
200
MUSCLES AND FASCIA.
then be divided in front at its junction with the malar bono, and, behind, near the exter-
nal auditory meatus, and drawn downwards with the masseter, which should be detached
from its insertion into the ramus and angle of the jaw. The whole extent of the Temporal
muscle is then exposed.
The Temporal is a broad radiating muscle, situated at the side of the head, and
occupying the entire extent of the temporal fossa. It arises from the whole of
the temporal fossa, which extends from the external angular process of the frontal
in front, to the mastoid portion of the temporal behind, and from the curved line
on the frontal and parietal bones above, to the pterygoid ridge on the great wing
of the sphenoid below. It is also attached to the inner surface of the temporal
fascia. Its fibres converge as they descend, the anterior passing obliquely back-
wards, the posterior obliquely forwards, and the middle fibres descend vertically,
and terminate in an aponeurosis, the fibres of wliich, radiated at its commence-
ment, converge into a thick and flat tendon, which is inserted into the inner surface,
apex, and anterior border of the coronoid process of the lower jaw.
Relations. By its superficial surface, with the integument, the temporal fascia,
aponeurosis of the Occipito-frontalis, the Attollens and Attrahens aurem muscles,
the temporal vessels and nerves, the zygoma and Masseter. By its deep surface,
with the temporal fossa, the External pterygoid and part of the Buccinator muscles,
the internal maxillary artery, and its deep temporal branches.
Nerves. Both muscles are supplied by the inferior maxillary nerve.
10. PtERTGO-M AXILLARY REGION.
Internal Pterygoid. External Pterygoid.
Dissection. The Temporal muscle having been examined, the muscles in the pterygo-
maxillary region may be exposed by sawing through the base of the coronoid process, and
drawing it upwards, together with the Temporal muscle, which should be detached from
the surface of the temporal fossa. Divide the ramus of the jaw just below the condyle,
and also, by a transverse incision extending across the commencement of its lower third,
just above the dental foramen, remove the fragment, and the Pterygoid muscles will be
exposed.
1 35- — The Pterygoid Muscles, the Zygomatic Arch and a portion of the
Eamus of the Jaw having been removed.
The Internal Pterygoid is a thick quadrilateral muscle, and resembles the
Masseter in form, structure, and in the direction of its fibres. It arises from the
I
PTERYGO-MAXILLARY REGION. 201
pterygoid fossa, its fibres being attached to the inner surface of the external ptery-
goid plate of the sphenoid, and to the grooved surface of tlie tuberosity of the
palate bone; its fibres descend downwards, outwards, and backwards, to be inserted,
by strong tendinous lamina3, into the lower and back part of the inner side of
the ramus and angle of the lower jaw.
Relations. By its external surface, with the ramus of the lower jaw, from which
it is separated at its upper part by the External Pterygoid, the internal lateral liga-
ment, the internal maxillary artery, and the superior dental vessels and nerves.
By its internal surjace, with the Tensor palati, being separated from the Superior
constrictor of the pharynx by a cellular interval.
The External Pterygoid is a short thick muscle, somewhat conical in form,
being broader at its origin than at its insertion. The two extremities of the
muscle are tendinous, the intervening portion being fleshy. It arises by two
heads, separated by a cellular interval. The upper head is attached to the ptery-
goid ridge on the great ala of the sphenoid, and the portion of bone included be-
tween it and the base of the external pterygoid plate; the other, the larger fasci-
culus, from the outer sur'face of the external pterygoid plate, and part of the
tuberosity of the palate bone. From this origin, its fibres proceed horizontally
backwards and outwards, to be inserted into a depression on the anterior part of
the neck of the condyle of the lower jaw, and into the corresponding part of
the interarticular fibro-cartilage.
Relations. By its external surface, with the ramus of the lower jaw, the inter-
nal maxillary artery, which crosses it, the tendon of the Temporal muscle, and
the Masseter. By its internal surface, it rests against the upper part of the
Internal pterygoid, the internal lateral ligament, the middle meningeal artery,
and inferior maxillary nerve; by its upper border it is in relation with the
temporal and masseteric branches of the inferior maxillary nerve.
Nerves. These muscles are supplied by the inferior maxillary nerve.
Actions. The Temporal, Masseter, and Internal pterygoid raise the lower jaw
against the upper with great force. The two latter muscles, from the obliquity
in the direction of their fibres, assist the External pterygoid in drawing the
lower jaw forwards upon the upper, the jaw being drawn back again by the deep
fibres of the Masseter, and posterior fibres of the Temporal. The External pte-
rygoid muscles are the direct agents in the trituration of the food, drawing the
lower jaw directly forwards, so as to make the lower teeth project beyond the
upper. If the muscle of one side acts, the corresponding side of the jaw is drawn
forwards, and the other condyle remaining fixed, the symphysis deviates to the
opposite side. The alternation of these movements on the two sides, produces
trituration.
MUSCLES AND FASCIA OF THE NECK.
The muscles of the Neck may be arranged into groups, corresponding with the
region in which they are situated.
These groups are nine in number.
1. Superficial Region. 6. Muscles of the Soft Palate.
2. Depressors of the Os Hyoides 7. Muscles of the Anterior Ver-
and Larynx. tebral Region.
3. Elevators of the Os Hyoides o ^^^ , ^ .1 t ^ i tt
and Lar nx ^" ^"^^^^^ ^^ *^^ Lateral Ver-
4. Muscles of &e Tongue. *^^^"^^ ^^S^^^'
9. Muscles of the Larynx.
5. Muscles of the Pharynx.
202
MUSCLES AND FASCIA.
I. Superficial Region.
Platysma myoides.
Sterno-cleido-mastoideus.
Infra-hyoid Regio7i.
2. Depressors of the Os Hyoides and
Larynx.
Sterno-hyoid.
Sterno-thyroid.
Thyro-hyoid.
Omo-hyoid.
Supra-hyoid Region.
3. Elevators of the Os Hyoides and
Larynx.
Digastric.
Stylo-hyoid.
Mylo-hyoid.
Genio-hyoid.
Lingual Region.
4. 3Iuscles of the Tongue.
Genio-hyo-glossus.
Hyo-glossus.
Lingualis.
Stylo-glossus.
Palato-fflossus.
5. Muscles of the Pharynx.
Constrictor inferior.
Constrictor medius.
Constrictor superior.
Stylo-pharyngeus.
Palato-pharyngeus.
6. Muscles of the Soft Palate.
Levator palati.
Tensor palati.
Azygos uvulae.
Palato-glossus.
Palato-pharyngeus.
7. Muscles of the Anterior Vertebral
Region.
Rectus capitis anticus major.
Rectus capitis anticus minor.
Rectus lateralis.
Longus colli.
8. Muscles of the Lateral Vertebral
Region.
Scalenus anticus.
Scalenus medius.
Scalenus posticus.
'9. Muscles of the Larynx.
Included in the description of the
Larynx.
Superficial Region, (fig. 131)-
Platysma Myoides.
Sterno-Cleido-Mastoid.
Dissection. A block having been placed at the back of the neck, and the face turned to
the side opposite to that to be dissected, so as to place the parts upon the stretch, two
transverse incisions are to be made: one from the chin, along the margin of the lower jaw,
to the mastoid process ; and the other along the upper border of the clavicle. These are
to be connected by an oblique incision made in the course of the Sterno-mastoid muscle,
from the mastoid process to the sternum ; the two flaps of integument having been
removed in the direction shewn in fig. 130, the superficial fascia will be exposed.
The Superficial Cervical Fascia is exposed on the removal of the integument
from the side of the neck; it is an extremely thin aponeurotic lamina, which is
hardly demonstrable as a separate membrane. Beneath it is found the Platysma
myoides muscle, the external jugular vein, and some superficial branches of the
cervical plexus of nerves.
The Platysma Myoides is a broad thin flat plane of muscular fibres, of an
irregular quadrilateral form, placed immediately beneath the skin on each side of
the neck. It arises from the clavicle and acroinion, and from the fascia covering
the upper part of the Pectoral, Deltoid, and Trapezius muscles; its fibres proceed
obliquely upwards and inwards along the side of the neck, to be inserted into the
lower jaw beneath the external obliqvie line, some fibres passing forwards to the
angle of the mouth, and others becoming lost in the cellular tissue of the face.
The most anterior fibres interlace, in front of the jaw, with the fibres of the
muscle of the opposite side; those next in order become blended with the Depres-
sor labii inferioris and the Depressor anguli oris; others are prolonged upon the
side of the cheek, and interlace, near the angle of the mouth, with the muscles in
this situation, and may occasionally be traced to the Zygomatic muscles, or to the
SUPERFICIAL CERVICAL REGION.
203
margin of the Orbicularis palpebrarum. The most posterior fibres, which are
lost in the skin at the side of the face, are the rudiments of a remarkable acces-
sory fasciculus, the Risorius Santorini, already described. Beneath this muscle,
the external jugular vein may be seen descending from the angle of the jaw to
the clavicle. It is essential to remember the direction of the fibres of the Pla-
tysma, in connection with the operation of bleeding from this vessel; for if the
point of the lancet is introduced in the direction of the fibres of this muscle, the
orifice made will be filled up by its contraction, and blood will not flow; but if
the incision is made in a direction opposite to that of the course of the fibres,
they will retract, and expose the orifice in the vein, and so facilitate the flow of
blood. This operation is now, however, very rarely performed.
Relations. By its extertial surface, with the integument, to which it is united
closely below, but more loosely above. By its internal surface, below the cla-
vicle which it covers, with the Pectoralis major. Deltoid, and Trapezius. In the
neck, with the external and anterior jugular veins, the deep cervical fascia, the
superficial cervical plexus, the Sterno-mastoid, Sterno-hyoid, Omo-hyoid, and
Digastric muscles. In front of the Sterno-mastoid, it covers the sheath of the
carotid vessels; and behind it, the Scaleni muscles and the nerves of the brachial
plexus. On the face, it is in relation with the parotid gland, the facial artery
and vein, and the Masseter and Buccinator muscles.
The Deep Cervical Fascia is exposed on the removal of the Platysma myoides.
It is a strong fibrous layer, which invests the muscles of the neck, and encloses
the vessels and nerves. It commences, as an extremely thin layer, at the back
part of the neck, where it is attached to the spinous processes of the cervical
vertebrae, and to the ligamentum nuchse; and, passing forwards to the posterior
border of the Sterno-mastoid muscle, divides into two layers, one of which passes
in front, and the other behind it. These join again at its anterior border; and,
being continued forwards to the front of the neck, blend with the fascia of the
opposite side. The superficial layer of the deep cervical fascia (that which passes
in front of the Sterno-mastoid), if traced upwards, is found to pass across the
parotid gland and Masseter muscle, forming the parotid and masseteric fascias,
and is attached to the lower border of the Zygoma, and more anteriorly to the
lower border of the body of the jaw; if the same layer is traced downwards, it is
seen to pass to the upper border of the clavicle and sternum, being pierced just
above the former bone for the external jugular vein. In the middle line of the
neck, this layer is thin above, and connected to the hyoid bone; but it becomes
thicker below, and divides, just below the thyroid gland, into two layers, the more
superficial of which is attached to the upper border of the sternum and inter-
clavicular ligament; the deeper and stronger layer is connected to the posterior
border of that bone, covering in the Sterno-hyoid and Sterno-thyroid muscles.
Between these two layers is a little areolar tissue and fat, and occasionally a
small lymphatic gland. The deep layer of the cervical fascia (that which lies
behind the postei'ior surface of the Sterno-mastoid) sends numerous prolongations,
which invest the muscles and vessels of the neck; if traced upwards, a process of
this fascia, of extreme density, passes behind and to the inner side of the parotid
gland, and is attached to the base of the styloid process and angle of the lower
jaw, forming the stylo-maxillary ligament; if traced downwards and outwards, it
will be found to enclose the posterior belly of the Omo-hyoid muscle, binding it
down by a distinct process, which descends to be inserted into the clavicle and
cartilage of the first rib. The deep layer of the cervical fascia also assists in
forming the sheath which encloses the common carotid artery, internal jugular
vein, and pneumogastric nerve. There are fibrous septa intervening between each
of these parts, which, however, are included together in one common investment.
More internally, a thin layer is continued across the trachea and thyroid gland,
beneath the Sterno-thyroid muscles; and at the root of the neck this may be
traced, over the large vessels, to be continuous with the fibrous layer of the
pericardium.
204
MUSCLES AND FASCIA.
The Sterno-Cleido- Mastoid (fig. 136) is a large thick muscle which passes
obliquely across the side of the neck, being enclosed between the two layers of
the deep cervical fascia. It is thick and narrow at its central part, but is broader
and thinner at each extremity. It arises, by two distinct heads, from the sternum
and clavicle. The sternal portion arises by a rounded fasciculus, tendinous in
front, fleshy behind, from the upper and anterior part of the first piece of the
sternum, and is directed upwards and backwards. The clavicular portion arises
from the inner third of the upper surface of the clavicle, being composed of fleshy
and aponeurotic fibres; it is directed perpendicularly upwards. These two por-
tions are separated from one another, at their origin, by a triangular cellular
interval; but become gradually blended, below the middle of the neck, into a
thick rounded muscle, which is inserted, by a strong aponeurosis, into the outer
surface of the mastoid process, from the apex to its superior border, and into the
136. — Muscles of the Neck, and Boundaries of the Triangles,
outer two- thirds of the superior curved line of the occipital bone. This muscle
varies much in its extent of attachment to the' clavicle: in one case it may be as
narrow as the sternal portion; in another, as much as three inches in breadth.
When the clavicular origin is broad, it is occasionally subdivided into numerous
slips, separated by narrow intervals. More rarely the corresponding margins of
the Sterno-mastoid and Trapezius have been found in contact. In the application
of a ligature to the third part of the subclavian artery, it will be necessary, where
the muscles have an arrangement similar to that above mentioned, to divide a
portion of one or of both, in order to facilitate the operation.
This muscle serves to divide the large quadrilateral space at the side of the
neck into two large triangles, an anterior and a posterior. The boundaries of the
great anterior triangle being, in front, the median line of the neck ; above, the
INFRA-IIYOID REGION.
205
lower border of the body of the jaw, and an imaginary line drawn from the angle
of the jaw to the mastoid process; behind, the anterior border of tlie Sterno-mastoid
muscle. The boundaries of the great posterior triangle are, in front, the poste-
rior border of the Sterno-mastoid; below, the upper border of the clavicle; behind,
the anterior margin of the Trapezius.
The anterior edge of this muscle forms a very prominent ridge beneath the
skin, which forms a gviide to the surgeon in making the incisions for ligature of
the common carotid artery, and for cesophagotomy.
Relations. By its superficial surface, with the integument and Platysma,
from which it is separated by the external jugular vein, the superficial branches
of the cervical plexus, and the anterior layer of the deep cervical fascia. By its
deep surface, it rests on the deep layer of the cervical fascia, the sterno- clavicular
articulation, the Sterno-hyoid, Sterno-thyroid, and Omo-hyoid muscles, the poste-
rior belly of the Digastric, Levator anguli scapula, the Splenius and Scaleni
muscles. Below, with the lower part of the common carotid artery, internal
jugular vein, pneumogastric, descendens noni, and communicans noni nerves, and
with the deep lymphatic glands; with the spinal accessory nerve, which pierces
its upper third, the cervical plexus, the sympathetic nerve, and the parotid gland.
Nerves. The Platysma-myoides is supplied by the facial and superficial cer-
vical nerves. The Sterno-cleido-mastoid by the spinal accessory and deep branches
of the cervical plexus.
Actions. The Platysma-myoides produces a slight wrinkling of the surface of
the skin of the neck, in a vertical direction, when the entire muscle is brought
into action. Its anterior portion, the thickest part of the muscle, depresses the
lower jaw; it also serves to draw down the lower lip and angle of the mouth on
each side, being one of the chief agents in the expression of melancholy. The
accessory transverse fibres draw the angle of the lips upwards and outwards, as
in laughing. The Sterno-mastoid muscles, when both are brought into action,
serve to depress the head upon the neck, and the neck upon the chest. Either
muscle, acting singly, flexes the head, and (combined with the Splenius) draws
it towards the shoulder of the same side, and rotates it so as to carry the face
towards the opposite side.
Infra-Hyoid Region (figs, 136, 137).
Depressors of the Os Hyoides and Larynx.
Sterno-Hyoid. Thyro-Hyoid.
Sterno-Thyroid. Omo-Hyoid.
Dissection. The muscles in this region may be exposed by removing the deep fascia
from the front of the neck. In order to see the entire extent of the Omo-hyoid, it is
necessary to divide the Sterno-mastoid at its centre, and turn its ends aside, and to detach
the Trapezius from the clavicle and scapula, if this muscle has been previously dissected ;
but not otherwise.
The Sterno-Hyoid is a thin, narrow, ribband-like muscle, which arises from
the inner extremity of the clavicle, and the upper and posterior part of the first
piece of the sternum; and, passing upwards and inwards, is inserted, by short
tendinous fibres, into the lower border of the body of the os hyoides. This
muscle is separated, below, from its fellow by a considerable interval; they approach
one another in the middle of their course, and again diverge as they ascend. It
often presents, immediately above its origin, a transverse tendinous intersection,
analogous to those in the Rectus abdominis.
Variations in Origin. The origin of this muscle presents many variations.
Thus, it may be found to arise from the inner extremity of the clavicle, and the
posterior sterno-clavicular ligament ; or from the sternum and this ligament ;
from either bone alone, or from all these parts; and occasionally has a fasciculus
connected with the cartilage of the first rib.
206
MUSCLES AND FASCIA.
Relations. By its superficial surface, below, with the sternum, sternal end of
the clavicle, and the Sterno-mastoid; and, above, with the Platysma and deep
cervical fascia. By its deep surface, with the Sterno-thyroid, Crico-thyroid, and
Thyro-hyoid muscles, the thyroid gland, the superior thyroid artery, the crico-
thyroid and thyro-hyoid membranes.
The Sterno- Thyroid is situated immediately beneath the preceding muscle, but
is shorter and broader than it. It arises from the posterior surface of the first
bone of the sternum, beneath the origin of the Sterno-hyoid, and occasionally
from the edge of the cartilage of the first rib; and is inserted into the oblique line
on the side of the ala of the thyroid cartilage. These muscles are in close contact
137. — Muscles of the Neck. Anterior View.
at the lower part of the neck by their inner margins; and are frequently traversed
by transverse or oblique tendinous intersections, analogous to those in the Rectus
abdominis.
Variations. This muscle, at its insertion, is liable to some variations. A lateral
prolongation is sometimes continued as far as the os hyoides; and it is sometimes
continuous with the Thyro-hyoideus and Inferior constrictor of the pharynx.
Relations. By its anterior surface, with the Sterno-hyoid, Omo-hyoid, and
Sterno-mastoid. By its posterior surface, from below upwards, with the trachea,
vena innominata, common carotid (and on the right side the arteria innominata),
the thyroid gland and its vessels, and the lower part of the larynx. The middle
thyroid vein lies along its inner border, this should be remembered in the operation
of tracheotomy.
The Thyro-Hyoid is a small quadrilateral muscle, appearing like a continuation
of the Sterno-thyroid. It arises from the oblique line on the side of the thyroid
cartilage, and passes vertically upwards to be inserted into the lower border of
the body, and greater cornu of the hyoid bone.
SUPRA-HYOID REGION.
207
Relations. By its external surface, with the Sterno-hyoid and Omo-hyoid
muscles. By its internal surface, with the thyroid cartilage, and thyro-hyoid
membrane. Interposed between this muscle and the membrane, is the superior
laryngeal nerve and artery.
The Omo-hyoid passes across the side of the neck, from the scapula to the
hyoid bone. It consists of two fleshy bellies, united by a central tendon. It
arises from the upper border of the scapula, and occasionally from the transverse
ligament which crosses the supra-scapular notch; its extent of attachment to the
scapula varying from a few lines to an inch. From this origin, the posterior
belly forms a flat, narrow fasciculus, which inclines forwards across the lower
part of the neck; behind the Sterno-mastoid muscle, where it becomes tendinous,
it changes its direction, forming an obtuse angle, and ascends almost vertically
upwards, close to the outer border of the Sterno-hyoid, to be inserted into the
lower border of the body of the os hyoides, just external to the insertion of the
Sterno-hyoid. The tendon of this muscle, which much varies in its length and
form in different subjects, is held in its position between two lamella of the deep
cervical fascia, which include it in a sheath, and are prolonged down to be
attached to the cartilage of the first rib. It is by this means that the angular
form of the muscle is maintained.
This muscle subdivides each of the two large triangles at the side of the neck,
formed by the Sterno-mastoid, into two smaller triangles. The two posterior
ones being the posterior superior or sub-occipital, and the posterior inferior or
subclavian; the two anterior, the anterior superior or superior carotid, and the
anterior inferior or inferior carotid triangle.
Relations. By its superficial surface, with the Trapezius, Subclavius, the
clavicle, the Sterno-mastoid, deep cervical fascia, Platysma, and integument. By
its deep surface, with the Scaleni, brachial plexus, sheath of the common carotid
artery, and internal jugular vein, the descendens noni nerve, Sterno-thyroid and
Thyro-hyoid muscles.
Nerves. All the muscles of this group, excepting the Thyro-hyoid, which is
supplied by the hypo-glossal, receive their nerves from the loop of communication
between the descendens and communicans noni.
Actions. These muscles serve to depress the larynx and hyoid bone, after these
parts have been drawn up with the pharynx in the act of deglutition. The Omo-
hyoid muscles not only depress the hyoid bone, but carry it backwards, and to
one or the other side. These muscles also are tensors of the cervical fascia. The
Thyro-hyoid may act as an elevator of the thyroid cartilage, when the hyoid bone
ascends, drawing upwards the thyroid cartilage behind the os hyoides.
Supra-Hyoid Region (figs. 136, 137).
Elevators of the Os Hyoides — Depressors of the Lower Jaw.
Digastricus. Mylo-Hyoid.
Stylo-Hyoid. Genio-Hyoid.
Dissection. To dissect these muscles, a block should be placed beneath the back of the
neck, and the head drawn backwards, and retained in that position. On the removal of
the deep fascia, the muscles are at once exposed.
The Digastric, so called from its consisting of two fleshy bellies united by an
intermediate rounded tendon, is a small muscle, situated immediately beneath the
side of the body of the lower jaw, and extending, in a curved form, from the side
of the head to the symphysis of the jaw. The posterior belly, longer than the
anterior, arises from the digastric groove on the inner side of the mastoid process
of the temporal bone, and passes downwards, forwards, and inwards. The ante-
rior belly, being reflected upwards and forwards, is inserted into a depression
2o8 MUSCLES AND FASCIA.
on the inner side of the lower border of the jaw, close to the symphysis. The
tendon of this muscle perforates the Stylo-hyoid, and is held in connection
with the side of the body of the hyoid bone by an aponeurotic loop, lined by a
synovial membrane. A broad aponeurotic layer is given oif from the tendon of
the digastric on each side, which is attached to the hyoid bone: this is termed the
supra-hyoid aponeurosis. It forms a strong layer of fascia between the anterior
portion of the two muscles, and forms a firm investment for the other muscles of
the supra-hyoid region, which lie beneath it.
The Digastric muscle divides the anterior superior triangle of the neck into
two smaller triangles; the upper, or sub-maxillary, being bounded above by the
lower jaw; below, by the two bellies of the Digastric muscle: the lower, or supe-
rior carotid triangle, being bounded above by the posterior belly of the Digastric;
behind, by the Sterno-mastoid; below, by the Omb-hyoid. (fig. 136).
Relations. By its superficial surface, with the Platysma, Sterno-mastoid, part
of the Stylo-hyoid muscle, and the parotid and sub-maxillary glands. By its deep
surface, its anterior belly lies on the Mylo-hyoid, the posterior belly lies on the
Stylo-glossus, Stylo-pharyngeus, and Hyo-glossus muscles, the external carotid
and its lingual and facial branches, the internal carotid, internal jugular vein, and
hypoglossal nerve.
The Stylo-Hyoid is a small, slender muscle, lying in front of, and above, the
posterior belly of the Digastric. It arises from the middle of the outer surface Of
the styloid process; and, passing downwards and forwards, is inserted into the
body of the hyoid bone, just at its junction with the greater cornu, and imme-
diately above the Omo-hyoid.
This muscle is perforated near its insertion by the tendon of the Digastric
muscle.
Relations. By its superficial surface, with the Sterno-mastoid and Digastric
muscles, the parotid and submaxillary glands. Its deep surface has the same
relations as the posterior belly of the Digastric.
Dissection. The Digastric and Stylo-hyoid muscles should be removed, in order to expose
the next muscle.
The Mylo-Hyoid is a flat triangular plane of muscular fibre, situated imme-
diately beneath the anterior belly of the Digastric, and forming, with its fellow
of the opposite side, a muscular floor for the cavity of the mouth. It arises from
the whole length of the mylo-hyoid ridge, from the symphysis in front, to the last
molar tooth behind. The posterior fibres pass obliquely forwards, to be inserted
into the body of the os hyoides. The middle and anterior fibres are inserted into
the median fibrous raphe, where they join at an angle with the fibres of the oppo-
site muscle. This median raphe is sometimes wanting; the muscular fibres of the
two sides are then directly continuous with one another.
Relations. By its superficial or inferior surface with the Platysma, the ante-
rior belly of the Digastric, the supra-hyoid fascia, the submaxillary gland, and
submental vessels. By its deep or superior surface, with the Genio-hyoid, part
of the Hyo-glossus, and Stylo-glossus muscles, the lingual and gustatory nerves,
the sublingual gland, and the buccal mucous membrane. Wharton's duct curves
around its posterior border in its passage to the mouth.
Dissection. The Mylo-hyoid should now be removed, in order to espose the muscles
which lie beneath; this is effected by detaching it from its attachments to the hyoid bone
and jaw, and separating it by a vertical incision from its fellow of the opposite side.
The Genio-Hyoid is a narrow slender muscle, situated immediately beneath the
inner border of the preceding. It arises from the inferior genial tubercle on the
inner side of the symphysis of the lower jaw, and descends downwards and back-
wards, to be inserted into the anterior surface of the body of the os hyoides. This
muscle lies in close contact with its fellow of the opposite side, and increases
slightly in breadth as it descends.
Relations. It lies between the Mylo-hyoid- and the Genio-hyo-glossus muscles.
LINGUAL REGION.
209
Nerves. The Digastric is supplied, its anterior belly, by the mylo-hyoid branch
of the inferior dental; its posterior belly, by the facial and glosso-pharyngeal; the
Stylo-hyoid, by the facial and glosso-pharyngeal; the Mylo-hyoid, by the mylo-
hyoid branch of the inferior dental; the Genio-hyoid, by the lingual.
Actiofis. This group of muscles performs two very important actions. They
raise the hyoid bone, and with it the base of the tongue, during the act of deglu-
tition ; or, when the hyoid bone is fixed by its depressors and those of the larynx,
they depress the lower jaw. During the first act of deglutition, when the mass is
being driven from the mouth into the pharynx, the hyoid bone, and with it the
tongue, is carried upwards and forwards by the anterior belly of the Digastric, the
Mylo-hyoid, and Genio-hyoid muscles. In the second act, when the mass is passing,
the direct elevation of the hyoid bone takes place by the combined action of all
the muscles; and after the food has passed, the hyoid bone is carried upwards and
backwards by the posterior belly of the Digastric and Stylo-hyoid muscles, which
assists in preventing the return of the morsel into the cavity of the movith.
Lingual Region.
Genio-Hyo-Glossus.
Hyo-Glossus.
Palato-Glossus.
Lingualis.
Stylo- Glossus.
Dissection. After completing the dissection of the preceding muscles, saw through the
lower jaw just external to the symphysis. The tongue should then be drawn forwards with
a hook, and its muscles, which are thus put on the stretch, may be examined
138. — Muscles of the Tongue. Left Side.
The Genio-Hyo-Glossus has received its name from its triple attachment
to the chin, hyoid bone, and tongue; it is a thin, flat, triangular muscle, placed
vertically in the middle line, its apex corresponding with its point of attachment
to the lower jaw, its base with its insertion into the tongue and hyoid bone. It
210 MUSCLES AND FASCIiE.
arises by a short tendon from the superior genial tubercle on the inner side of the
symphysis of the chin, immediately above the Genio-hyoid; from this point the
muscle spreads out in a fan-like form, the inferior fibres passing downwards, to be
inserted into the upper part of the body of the hyoid bone, a few being continued
into the side of the pharynx; the middle fibres passing backwards, and the an-
terior ones upwards and forwards, to be attached to the whole length of the
under surface of the tongue, from the base to the apex.
Relations. By its internal surface, it is in contact with its fellow of the opposite
side, from which it is separated, at the back part of the tongue, by a fibro-cellular
structure, which extends forwards through the middle of the organ. By its
external surface, with the Lingualis, Hyo-glossus, and Stylo-glossus, the lingual
artery and hypoglossal nerve, the gustatory nerve, and the sublingual gland.
By its upper border, with the mucous membrane of the floor of the mouth. By its
lower border, with the Genio-hyoid.
The Hyo- Glossus is a thin, flat, quadrilateral plane of muscular fibres, arising
from the body, the lesser cornu, and whole length of the greater cornu of the
hyoid bone, and passing almost vertically upwards, is inserted into the side of the
tongue, between the Stylo-glossus and Lingualis. Those fibres of this muscle
which arise from the body are directed upwards and backwards, overlapping those
from the greater cornu, which are directed obliquely forwards. Those from the
lesser cornu extend forwards and outwards along the side of the tongue, under
cover of the portion arising from the body.
The difference in the direction of the fibres of this muscle, and their separate
origin from different segments of the hyoid bone, led Albinus and other anato-
mists to describe it as three muscles, under the names of the Basio-glossus, the
Cerato-glossus, and the Chondro-glossus.
Relations. By its external surface, with the Digastric, the Stylo-hyoid, Stylo-
glossus, and Mylo-hyoid muscles, the gustatory and hypoglossal nerves, Wharton's
duct, and the sublingual gland. By its deep surface, with the Genio-hyo-glossus,
Lingualis, and the origin of the middle Constrictor muscle of the pharynx, the
lingual artery, and the glosso-pharyngeal nerve.
The Lingualis is a longitudinal band of muscular fibres, situated on the under
surface of the tongue, lying in the interval between the Hyo-glossus and the
Genio-hyo-glossus, and extending from the base to the apex of that organ. Pos-
teriorly, some of its fibres are lost in the base of the tongue, and others are
attached to the hyoid bone. It blends with the fibres of the Stylo-glossus, in
front of the Hyo-glossus, and is continued forwards as far as the apex of the
tongue. It is in relation, by its under surface, with the ranine artery.
The Stylo- Glossus, the shortest and smallest of the three styloid muscles,
arises from the anterior and outer side of the styloid process, near its centre, and
from the stylo-maxillary ligament, to Avhich its fibres in most cases are attached
by a thin aponeurosis. Passing downwards and forwards, so as to become nearly
horizontal in its direction, it divides upon the side of the tongue into two portions;
one longitudinal, which is inserted along the side of the tongue, blending with the
fibres of the Lingualis, in front of the Hyo-glossus; the other oblique, which
overlaps the Hyo-glossus muscle, and decussates with its fibres.
Relations. By its external surface, from above downwards, with the parotid
gland, the Internal pterygoid muscle, the sublingual gland, the gustatory nerve,
and the mucous membrane of the mouth. By its internal surface, with the tonsil,
the Superior constrictor muscle of the pharynx, and the Hyo-glossus muscle.
The Palato- Glossus, or Constrictor Isthmi Faucium, although one of the mus-
cles of the tongue, serving to draw its base upwards during the act of deglutition,
is more nearly associated with the soft palate, both in its situation and function;
it will, consequently, be described with that group of muscles.
Nerves. The muscles of the tongue are supplied by the hypoglossal nerve,
excepting the Palato-glossus, which receives its nerves from the palatine branches
of Meckel's ganglion.
PHARYNGEAL REGION.
211
Actions. The movements of the tongue, although numerous and complicated,
may easily be explained by cai-efully considering the direction of the fibres of the
muscles of this organ. The Genio-hyo-glossi, by means of their posterior and
inferior fibres, draw upwards the hyoid bone, bringing it and the base of the tongue
forwards, so as to protrude the apex from the mouth. The anterior fibres will restore
it to its original position by retracting the organ within the mouth. The whole
length of these two muscles acting along the middle line of the tongue will draw
it downwards, so as to make it concave from before backwards, forming a channel
along which fluids may pass towards the pharynx, as in sucking. The Hyo-glossi
muscles draw down the sides of the tongue, so as to render it convex from side to
side. The Linguales, by drawing downwards the centre and apex of the tongue,
render it convex from before backwards. The Palato-glossi draw the base of the
tongue upwards, and the Stylo-glossi upwards and backwards.
I
Pharyngeal Region.
Constrictor Inferior. Constrictor Superior.
Constrictor Medius. Stylo -pharyngeus.
Palato-pharyngeus.
Dissection (fig. 139). In order to examine the muscles of the pharynx, cut through the
trachea and oesophagus just above the sternum, and draw them upwards by dividing the
loose areolar tissue connecting
the pharynx with the front of 139. — Muscles of the Pharynx. External View,
the vertebral column. The parts
being drawn well forwards, the
edge of the saw should be applied
immediately behind the styloid
processes, and the base of the
skull sawn through from below
upwards. The pharynx and
mouth should then be stuffed
with tow, in order to distend its
cavity and render the muscles
tense and easier of dissection.
The Inferior Constrictor,
the most superficial and thick-
est of the three, arises from
the side of the cricoid and
thyroid cartilages. To the
cricoid cartilage it is attached
in the interval between the
crico-thyroid, in front, and the
articular facet for the thyroid
cartilage behind. To the thy-
roid cartilage, it is attached
to the oblique line on the side
of the great ala, the cartilagi-
nous surface behind it, nearly
as far as its posterior border,
and to the inferior cornu.
From these attachments, the
fibres spread backwards and inwards, to be inserted into the fibrous raphe in the
posterior median line of the pharynx. The inferior fibres are horizontal, and
overlap the commencement of the oesophagus; the rest ascend, increasing in obli-
quity, and overlap the Middle constrictor. The superior laryngeal nerve passes
near the upper border, and the inferior, or recurrent laryngeal, beneath the lower
border of this muscle, previous to their entering the' larynx.
Relations. It is covered by a dense cellular membrane which surrounds the
p 2
212 MUSCLES AND FASCIiE.
entire pharynx. Behind, it lies on the vertebi*al column and the Longus colli.
Laterally, it is in relation with the thyroid gland, the common carotid artery, and
the Sterno-thyroid muscle. By its internal surface, with the Middle constrictor,
the Stylo-pharyngeus, Palato-pharyngeus, and the mucous membrane of the
pharynx.
The Middle Constrictor is a flattened, fan-shaped muscle, smaller than the pre-
ceding, and situated on a plane anterior to it. It arises from the whole length of
the upper border of the greater cornu of the liyoid bone, from the apex of this
cornu by a tendinous origin, from the lesser cornu, and from the stylo-hyoidean
ligament. The fibres diverge from their origin in various directions; the lower
ones descending and being overlapped by the inferior constrictor, the middle fibres
passing transversely, and the upper fibres ascending to cover in the Superior con-
strictor. It is inserted into the posterior median' fibrous raphe, blending in the
middle line with the fibres of the opposite muscle.
Relations. This muscle is separated from the Superior constrictor by the glosso-
pharyngeal nerve and the Stylo-phai-yngeus muscle; and from the inferior constric-
tor, by the superior laryngeal nerve. Behind, it lies on the vertebral column, the
Longus colli, and the Rectus anticus major. On each side it is in relation with the
carotid vessels, the pharyngeal plexus, and some lymphatic glands. Near its
origin, it is covered by the hyo-glossus, from which it is separated by the lingual
artery. It covers in the Superior constrictor, the Stylo-pharyngeus, the Palato-
pharyngeus, and the mucous membrane.
The Superior Constrictor is a quadrilateral plane of muscular fibres, thinner
and paler than those of the other Constrictors, situated at the upper part of the
pharynx. It arises from the lower third of the margin of the internal pterygoid
plate and its hamular process, from the contiguous portion of the palate bone and
the reflected tendon of the Tensor palati muscle, from the pterygo-maxillary liga-
ment, from the alveolar process above the posterior extremity of the mylo-hyoid
ridge, and by a few fibres from the side of the tongue in connexion with the Genio-
hyo-glossus. From these points, the fibres curve backwards, to be inserted into
the median raphe, being also prolonged by means of a fibrous aponeurosis to
the pharyngeal spine on the basilar process of the occipital bone. Its superior
fibres arch beneath the Levator palati and the Eustachian tube, the interval
between this border of the muscle and the basilar process being deficient in mus-
cular fibres, and closed by fibrous membrane.
Relations. By its outer surface, behind, with the vertebral column. On each
side, with the carotid vessels, the internal jugular vein, the three divisions of the
eighth and the ninth nerves, the Middle constrictor which overlaps it, and the
Stylo-pharyngeus. Internally, it covers the Palato-pharyngeus and the tonsil and
is lined by mucous membrane.
The Stylo-pharyngeus is a long, slender muscle, round above, broad and thin
below. It arises from the inner side of the base of the styloid process, passes
downwards and inwards to the side of the pharynx between the Superior and
Middle constrictors, and spreading out beneath the mucous membrane, some of its
fibres are lost in the Constrictor muscles, and others joining with the Palato-
pharyngeus, are inserted into the posterior border of the thyroid cartilage. The
glosso-pharyngeal nerve runs on the outer side of this muscle, and crosses over it
in passing forward to the tongue.
Relations. Externally, with the Stylo-glossus muscle, the external carotid
artery, the parotid gland, and the Middle constrictor. Internally, with the inter-
nal carotid, the internal jugular vein, the Superior constrictor, Palato-pharyngeus
and mucous membrane.
Nerves. The muscles of this group are supplied by branches from the pharyn-
geal plexus and glosso-pharyngeal nerve; and the Inferior constrictor, by an addi-
tional branch from the external laryngeal nerve.
Actions. When deglutition is about to be performed, the pharynx is drawn
upwards and dilated in diflerent directions, to receive the morsel propelled into it
PALATAL REGION.
213
from the mouth. The Stylo-pharyngei, which are much farther removed from one
another at their origin than at their insertion, draw upwards and outwards the
sides of this cavity, the breadth of the pharynx in the antero-posterior direction
being increased, by the larynx and tongue being carried forwards in their ascent.
As soon as the morsel is received in the pharynx, the elevator muscles relax, the
bag descends, and the Constrictors contract upon the morsel, and convey it gradually
downwards into the oesophagus. The pharynx also exerts an important influence
in the modulation of the voice, especially in the production of the higher tones.
Palatal Region.
Levator Palati. Azygos Uvulae.
Tensor Palati. Palato-glossus,
Palato-pharyngeus.
Dissection (fig. 140). Lay open the pharynx from behind, by a vertical incision extending
from its upper to its lower part, and the posterior surface of the soft palate is exposed.
Having fixed the uvula so as to make it tense, the mucous membrane and glands should
be carefully removed from the posterior surface of the soft palate and the muscles of this
part are at once exposed.
140.— Muscles of the Soft Palate. The Pharynx being laid open from behind.
"> /I h a <j''
The Levator Palati is a long, thin muscle, placed on the outer side of the pos-
terior aperture of each nasal fossa. It arises from the apex of the basilar surface
of the petrous portion of the temporal bone and from the adjoining cartilaginous
portion of the Eustachian tube; after passing into the interior of the pharynx,
above the upper concave margin of the Superior constrictor, it descends obliquely
downwards and inwards, its fibres spreading out in the posterior surface of the
214 MUSCLES AND FASCIA.
soft palate as far as the middle line, where they blend with those of the opposite
side.
Relations. Externally, with the Tensor palati and Superior constrictor. Inter-
nally, it is lined by the mucous membrane of the pharynx. Posteriorly, with the
mucous lining of the soft palate. This muscle must be removed and the pterygoid
attachment of the Superior constrictor dissected away, in order to expose the next
muscle.
The Circumflexus or Tensor Palati is a broad, thin, flat muscle, placed on the
outer side of the preceding, and consisting of two distinct portions, a vertical and
horizontal. The vertical portion arises by a broad, thin, and flat lamella from the
scaphoid fossa at the base of the internal pterygoid plate, its fibres of origin
extending as far back as the spine of the sphenoid; it also arises from the anterior
aspect of the cartilaginous portion of the Eustachian tube, descending vertically
downwards between the internal pterygoid plate and the inner surface of the
Internal pterygoid muscle; it terminates in a tendon which winds around the
hamular process, being retained in this situation by a tendon of origin of the
Internal pterygoid muscle, and lubricated by a synovial membrane. The tendon
or horizontal portion then passes horizonally inwards, and expands into a broad
aponeurosis on the anterior surface of the soft palate, which unites in the median
line with the aponeurosis of the opposite muscle, the fibres of which are attached
anteriorly to the transverse ridge on the posterior border of the horizontal portion
of the palate bone,
Relations. Externally, with the Internal pterygoid. Internally, with the
Levator palati, from which it is separated by the Superior constrictor, and the in-
ternal pterygoid plate. In the soft palate its aponeurotic expansion is anterior to
that of the Levator palati, being covered by mucous membrane.
The Azygos UvuIcb is not a single muscle as implied by its name, but a pair of
small cylindrical fleshy fasciculi, placed side by side in the median line of the soft
palate. Each muscle arises from the posterior nasal spine of the palate bone,
and from the contiguous tendinous aponeurosis of the soft palate, and descending
vertically downwards, is inserted into the uvula.
Relations. Anteriorly, with the tendinous expansion of the Levatores palati;
behind, with the mucous membrane.
The two next muscles are exposed by removing the mucous membrane which covers the
pillars of the soft palate on each side throughout their whole extent.
The Palato- Glossus (or. Constrictor Isthmi Eaucium) is a small fleshy fasci-
culus, narrower in the middle than at either extremity, forming, with the mucous
membrane covering its surface, the anterior pillar of the soft palate. It arises from
the soft palate on each side of the uvula, and passing forwards and outwards in
front of the tonsil, is inserted into the side and upper surface of the tongue, where
it blends with the fibres of the Stylo-glossus muscle. In the soft palate, the fibres
of origin of this muscle are continuous with those of the opposite side, and with
the Palato-pharyngeus.
The Palato-Pharyngeus is a long fleshy fasciculus, narrower in the middle
than at either extremity, forming, with the mucous membrane covering its surface,
the posterior pillar of the soft palate. It is separated from the preceding by an
angular interval, in which the tonsil is lodged. It arises from the soft palate by an
expanded fasciculus, its fibres being divided into two unequal parts by the Levator
palati, and being continuous partly with the muscle of the opposite side, and
partly with the fibrous aponeurosis of the palate. Passing outwards and down-
wards behind the tonsil, it joins the Stylo-pharyngeus, and is inserted with it into
the posterior border of the thyroid cartilage, some of its fibres being lost on the
side of the pharynx.
Relations. In the soft palate, its anterior and posterior surfaces are covered by
mucous membrane, from which it is separated by a layer of palatine glands. By
its superior border, it is in relation with the Levator palati. Where it forms the
posterior pillar of the fauces, it is covered by mucous membrane, excepting on its
ANTERIOR VERTEBRAL REGION.
215
outer surface. In the pharynx, it lies between the mucous membrane and the
constrictor muscles.
Nerves. The Tensor jjalati ia supplied by a branch from the otic ganglion; the
other muscles by the palatine branches of Meckel's ganglion.
Actions. When the morsel of food has been driven backwards into the fauces
by the pressure of the tongue against the hard palate, the Palato-glossi muscles,
the constrictors of the fauces, contract behind it, the soft palate is slightly raised
(by the Levator palati), and made tense (by the Tensor palati), and the Palato-
pharyngtei contract, and come nearly together, the Uvula filling up the slight
interval between them. By these means, the food is prevented passing into the
upper part of the pharynx or the posterior nares; at the same time the latter
muscles form an inclined plane, directed obliquely downwards and backwards,
along which the morsel descends into the pharynx.
Surgical Anatomy. The muscles of the soft palate should be carefully dissected, the rela-
tions they bear to the surrounding parts especially examined, and their action attentively
studied upon the dead subject, as the surgeon is required to divide one or more of these
muscles in the operation of staph yloraphy. Mr. Ferguson has shewn, that in the con-
genital deficiency, called cleft palate, the edges of the fissure are forcibly separated by the
action of the Levatores palati and Palato-pharyngsei muscles, producing very considerable
impediment to the healing process after the performance of the operation for uniting their
margins by adhesion ; he has, consequently, recommended the division of these muscles as
one of the most important steps in the operation : by these means, the flaps are relaxed,
lie perfectly loose and pendulous, and are easily brought and retained in apposition. The
Palato-pharynggei may be divided by cut^^ing across the posterior pillar of the soft palate,
just below the tonsil, with a pair of blunt-pointed curved scissors, and the anterior pillar
may be divided also. To divide the Levator palati, the plan recommended by Mr. Pollock
is to be greatly preferred. The flap being put upon the stretch, a double-edged knife is
passed through the soft palate just on the inner side of the hamular process, and above the
line of the Levator palati. The handle being now alternately raised and depressed, a
sweeping cut is made along the posterior surface of the soft palate, and the knife with-
drawn, leaving but a small opening in the mucous membrane on the anterior surface. If
this operation is performed on the dead body, and the parts afterwards dissected, the
Levator palati will be found completely divided.
Vertebral Region (Anterior).
Rectus Capitis Anticus Major. Rectus Lateralis.
Rectus Capitis Anticus Minor. Longus Colli.
The Rectus Capitis Anticus Major (fig. 14 1), broad and thick above, narrow
below, appears like a continuation upwards of the Scalenus anticus. It arises by
four tendons from the anterior tubercles of the transverse processes of the third,
fourth, fifth, and sixth cervical vertebrge, and ascends, converging towards its
fellow of the opposite side, to be inserted into the basilar process of the occipital
bone.
Relations. By its anterior surface, with the pharynx, the sympathetic nerve,
and the sheath enclosing the carotid artery, internal jugular vein, and pneumo-
gastric nerve. By its posterior surface, with the Longus colli, the Rectus anticus
minor, and the upper cervical vertebrae.
The Rectus Capitis Anticus Minor is a short muscle, situated immediately
beneath the upper part of the preceding. It arises from the anterior surface of
the lateral mass of the atlas, and from the root of its transverse process; passing
obliquely upwards and inwards, it is inserted into the basilar process immediately
behind the preceding muscle.
Relations. By its anterior surface, with the Rectus anticus major. By its
posterior surface, with the anterior part of the occipito-atlantai articulation.
Externally, with the superior cervical ganglion of the sympathetic.
The Rectus Lateralis is a short, flat muscle, situated between the transverse
process of the atlas, and the jugular process of the occipital bone. It arises from
2 {6 MUSCLES AND FASCIA.
the upper surface of the transverse process of the atlas, and is inserted into the
under surface of the jugular process of the occipital bone.
Relations. By its anterior surface, with the internal jugular vein. By its
posterior surface, with the vertebral artery.
The Longus Colli is a long, flat muscle, situated on the anterior surface of the
spine, between the atlas and the third dorsal vertebra, being broad in the middle,
narrow and pointed at each extremity. It consists of three portions, a superior
oblique, an inferior oblique, and a vertical portion.
The superior oblique portion arises by a narrow tendon from the tubercle on
the anterior arch of the atlas, and descending obliquely outwards, is inserted into
the anterior tubercles of the transverse processes of the third, fourth, and fifth
cervical vertebrae.
The inferior oblique portion, the smallest part of the muscle, arises tendinous
141.— The Pre- Vertebral Muscles.
from the transverse processes of the fifth and sixth cervical vertebras, and passing
obliquely inwards, is inserted into the bodies of the first two or three dorsal vertebrae.
The vertical portion lies directly on the front of the spine, and is extended
between the bodies of the second, third, and fourth cervical vertebrae above, and
the bodies of the three lower cervical and the three upper dorsal below.
Relations. By its anterior surface, with the pharynx, the oesophagus, sympa-
thetic nerve, the sheath of the carotid artery, internal jugular vein, and pneumo-
gastric nerve, inferior thyroid artery, and recurrent laryngeal nerve. By its
posterior surface, with the cervical and dorsal portions of the spine.
latp:ral vertebral region. 217
Vertebral Region (Lateral).
Scalenus Anticus. Scalenus Medius.
Scalenus Posticus.
The Scalenus Anticus is a triangular muscle, situated deeply at the side of the
neck, behind the Sterno-mastoid. It arises by a narrow, flat tendon from the
tubercle on the inner border and upper surface of the first rib, and ascending ver-
tically upwards, is inserted into the anterior tubercles of the transverse processes
of the third, fourth, fifth, and sixth cervical vertebrae. The lower part of this
muscle separates the subclavian artery and vein; the latter being in front, and the
former, with the brachial plexus, behind.
Relations. By its anterior surface, with the Sterno-mastoid and Omo-hyoid
muscles, the transversalis Colli, and descending cervical arteries, and the phrenic
nerve. By its posterior surface, with the subclavian artery, and brachial plexus
of nerves. It is separated from the Longus colli on the inner side by the subcla-
vian artery.
The Scalenus Medius, the largest and longest of the three Scaleni, arises, by a
broad origin, from the upper surface of the first rib, behind the groove for the
subclavian artery, as far back as the tubercle, and ascending along the side of the
vertebral column, is inserted, by separate tendinous slips, into the posterior tuber-
cles of the transverse processes of the six lower cervical vertebras. It is separated
from the Scalenus anticus by the subclavian artery below, and the cervical nerves
above.
Relations. By its external surface, with the Sterno-mastoid; it is crossed by the
clavicle and Omo-hyoid muscle. To its outer side, is the Levator anguli scapulae
and the Scalenus posticus muscle.
The Scalenus Posticus, the smallest of the three Scaleni, arises by a thin tendon
from the outer surface of the second rib, behind the attachment of the Serratus
magnus, and enlarging as it ascends, is inserted, by two or three separate tendons,
into the posterior tubercles of the transverse processes of the two or three lower
cervical vertebrfe. This is the most deeply-placed of the three Scaleni, and is
occasionally blended with the Scalenus medius.
Nerves. The Rectus capitis anticus major and minor are supplied by the sub-
occipital and deep branches of the cervical plexus; the Rectus lateralis by the
sub-occipital; and the Longus colli and Scaleni by branches from the lower cer-
vical nerves.
Actions. The Rectus anticus major and minor are the direct antagonists of
those placed at the back of the neck, serving to restore the head to its natural
position when drawn backwards by the posterior muscles. These muscles also
serve to bow the head forwards. The Longus colli will flex and slightly rotate
the cervical portion of the spine. The Scaleni muscles, taking their fixed point
from below, draw down the transverse processes of the cervical vertebrae, flexing
the spinal column to one or the other side. If the muscles of both sides act, the
spine will be kept erect. When taking their fixed point from above, they elevate
the first and second ribs, and are, therefore, inspiratory muscles.
MUSCLES AND FASCIA OF THE TRUNK.
The muscles of the Trunk may be subdivided into four groups.
1 . Muscles of the Back. 3. Muscles of the Thorax.
2. Muscles of the Abdomen. 4. Muscles of the Perinaeum.
The Muscles of the Back are very numerous, and may be subdivided into five
layers.
First Layer. Second Layer.
Trapezius. Levator anguli scapulae.
Latissimus dorsi. Rhomboideus minor.
. . Rhomboideus major.
2l8
MUSCLES AND FASCIA.
Third Layer.
Serratus posticus superior.
Serratus posticus inferior.
Splenius capitis.
Splenius colli.
Fourth Later.
Sacral and Lumbar Regions.
Erector Spinae.
Dorsal Region.
Sacro-lumbalis.
Musculus accessorius ad sacro-lumbalem.
Longissimus dorsi.
Spinalis dorsi.
Cervical Region.
Cervicalis ascendens.
Transversalis cervicis.
Trachelo-mastoid.
Complexus.
Biventer cervicis.
Spinalis cervicis.
Fifth Layer.
Semi-spinalis dorsi.
Semi- spinalis colli.
Multifidus spinae.
Rotatores spinae.
Supra-spinales.
Inter-spinales.
Extensor coccygis.
Inter- transversales.
Rectus posticus major.
Rectus posticus minor.
Obliquus superior.
Obliquus inferior.
First Layer.
Trapezius.
Latissimus Dorsi.
Dissection {^g.T^^). The body sbould be placed in the prone position, with the arms
extended over the sides of the table, and the chest and abdomen supported by several
blocks, so as to reuder the muscles tense. An
142.— Dissection of the Muscles of the Back, incision should then be made along the middle
line of the back, from the occipital protu-
berance £0 the coccyx. From the upper end
of this, a transverse incision should extend to
the mastoid process ; and from the lower end
a third incision should be made along the
crest of the ilium to about its middle. This
large intervening space, for convenience of
dissection, should be subdivided by a fourth
incision, extending obliquely from the spinous
process of the last dorsal vertebra, upwards
and outwards, to the acromion process. This
incision corresponds with the lower border of
the Trapezius muscle. The flaps of integu-
ment should then be removed in the direction
shewn in the accompanying figure.
The Trapezius is a broad, flat, trian-
gular muscle, placed immediately beneath
the skin, and covering the upper and back
part of the neck and shoulders. It arises
from the occipital protuberance and inner
third of the superior curved line of the
occipital bone ; from the ligamentum
nuchae, the spinous processes of the
seventh cervical, and all the dorsal ver-
tebrae, and from the corresponding por-
tion of the supra-spinous ligament. From
these points the muscular fibres proceed,
the superior ones downwards and out-
wards, the inferior ones upwards and
outwards, and the middle fibres horizon-
tally, and are inserted, the superior ones curving forwards into the outer third of
the posterior border of the clavicle, the middle fibres into the upper margin of the
acromion process, and into the whole length of the upper border of the spine of
the scapula; the inferior fibres converge near the scapula, and are attached
OF THE BACK.
219
143. — Muscles of the Back. On the Left Side is exposed the First Layer;
on the Eight Side, the Second Layer and part of the Third.
220 MUSCLES AND FASCIA.
to a triangular aponeurosis, which glides over a small triangular surface at the
inner extremity of the spine, and is inserted into a small tubercle in immediate
connection with its outer part. The Trapezius is fleshy in the greater part of
its extent, but tendinous at its origin and insertion. At its occipital origin, it is
connected to the bone by a thin fibrous lamina, firmly adherent to the skin, and
wanting the lustrous, shining appearance of aponeurosis. At its origin from the
spines of the vertebrje, it is connected by means of a broad semi-elliptical aponeu-
rosis, which occupies the space between the sixth cervical and the third dorsal
vertebrae, and forms, with the muscle of the opposite side, a tendinous ellipse.
The remaining part of the origin is effected by numerous short tendinous fibres.
If the Trapezius is dissected on both sides, the two muscles resemble a trapezium,
or diamond-shaped quadrangle; two angles, corresponding to the shoulders; a
third, to the occipital protuberance; and the fourth, to the spinous process of the
last dorsal vertebra.
The clavicular insertion of this muscle varies as to the extent of its attachment;
it sometimes advances as far as the middle of the clavicle, and may even become
blended with the posterior edge of the Sterno-mastoid, or overlap its margin. This
should be borne in mind in the operation for tying the subclavian artery.
Relations. By its superficial surface, with the integument^ to which it is closely
adherent above, but separated below by an aponeurotic lamina. By its deep sur-
face, in the neck, with the Complexus, Splenius, Levator anguli scapulae, and
Rhomboideus minor; in the back, with the Rhomboideus major, Supra-spinatus,
Infra-spinatus, a small portion of the Serratus posticus superior, the intervertebral
aponeurosis which separates it from the Erector spinae, and with the Latissimus
dorsi. The spinal accessory nerve passes beneath the anterior border of this
muscle, near the clavicle. The outer margin ©f its cervical portion forms the
posterior boundary of the large posterior triangle of the neck, the other boundaries
being the Sterno-mastoid in front, and the clavicle below.
The Lig amentum Nuchm (fig. 1 43) is a thin band of condensed cellulo-fibrous
membrane, placed in the line of union between the two Trapezii in the neck. It
extends from the external occipital protuberance to the spinous process of the
seventh cervical vertebra, where it is continuous with the supra-spinous ligament.
From its anterior surface a fibrous slip is given off to the spinous processes of
each of the cervical vertebra, excepting the atlas, so as to form a septum between
the muscles on each side of the neck. In the human subject, it is merely the rudi-
ment of an important elastic ligament, which serves to sustain the weight of the
head in some of the lower animals.
The Latissimus Dorsi is a broad flat muscle, which covers the lumbar and
lower half of the dorsal regions, and is gradually contracted into a narrow fasci-
culus at its insertion into the humerus. It arises by tendinous fibres from the
spinous processes of the six inferior dorsal, from those of the lumbar and sacral
vertebrse, and from the supra-spinous ligament. Over the sacrum, the aponeurosis
of this muscle blends with the tendon of the Erector spinte. It also arises from
the external lip of the crest of the ilium, behind the origin of the External oblique,
and by fleshy digitations from the three or four lower ribs, being interposed be-
tween similar processes of the External oblique muscle. From this extensive
origin the fibres pass in different directions,, the upper ones horizontally, the
middle ones obliquely upwards, and the lower ones vertically upwards, so as to
converge and form a thick fasciculus, which crosses the inferior angle of the
scapula, and occasionally receives a few fibres from it. The muscle then curves
around the lower border of the Teres major, and is twisted upon itself, so that
the superior fibres become at first posterior and then inferior, and the vertical
fibres at first anterior and then superior. It then terminates in a short quadri-
lateral tendon, about three inches in length, which, passing in front of the tendon
of the Teres major, is inserted into the bottom of the bicipital groove of the humerus,
above the insertion of the tendon of the Pectoralis major. The lower border of
the tendon of this muscle is united with that of the Teres major, the surfaces of
i
OF THE BACK. 221
the two being separated by a synovial bursa; a second synovial bursa is interposed
between the muscle and the inferior angle of the scapula.
The origin of this muscle from the spine and ilium is effected by an aponeu-
rosis, which assists in forming the sheath for the Erector spinas. Its costal
attachment takes place by means of three or four fleshy slips, which inter-digitate
with the External oblique muscle of the abdomen.
Relations. Its superficial stirface is subcutaneous, excepting at its upper part,
where it is covered by the Trapezius. By its deep surface, it is in relation with
the Erector spinas, the Serratus posticus inferior. Intercostal muscles and ribs, the
Serratus magnus, inferior angle of the scapula, Rhomboideus major, Infra-spinatus,
and Teres major. Its external margin is separated below, from the external
oblique, by a small triangular interval; and another triangular interval exists
between its superior border and the margin of the Trapezius, in which the Inter-
costal and Rhomboideus major muscles are exposed.
Nerves. The Trapezius is supplied by the spinal accessory and cervical plexus;
the Latissimus dorsi, by the subscapular nerves.
Second Layer.
Levator Anguli Scapulas. Rhomboideus Minor.
Rhomboideus Major.
Dissection. The Trapezius must be removed in order to expose the next layer ; to effect
this, the muscle must be detached from its attachment to the clavicle and spine of the
scapula, and turned back towards the spine.
The Levator Anguli Scapulce is a long, thick, and somewhat flattened muscle,
situated at the posterior part and side of the neck. It arises by four tendons from
the posterior tubercles of the transverse processes of the three or four upper cer-
vical vertebras, these becoming fleshy are united so as to form a flat muscle, which,
passing downwards and backwards, is inserted into the posterior border of the
scapula, between the superior angle and the triangular smooth surface at the root
of the spine.
Relations. By its superficial surface, with the integument, Trapezius, and
Sterno-mastoid. By its deep surface, with the Splenius colli, Transversalis colli,
Cervicalis ascendens, and Serratus posticus superior, and with the transverse cer-
vical and posterior scapular arteries.
The Rhomboideus Minor arises from the ligamentum nuchre, and spinous pro-
cesses of the seventh cervical and first dorsal vertebrae, its fibres of origin being
intimately united with those of the Trapezius. Passing downwards and outwards,
it is inserted into the margin of the triangular smooth surface at the root of the
spine of the scapula. This small muscle is usually separated from the Rhom-
boideus major by a slight cellular interval.
The Rhomboideus Major is situated immediately below the preceding, the adja-
cent margins of the two being occasionally united. It arises by tendinous fibres
from the spinous processes of the four or five upper dorsal vertebrse and their
inter-spinous ligaments, and is inserted into the posterior border of the scapula,
between the triangular surface at the base of the spine and the inferior angle.
The insertion of this muscle takes place by means of a narrow, tendinous arch,
attached above, to the triangular surface near the spine; below, to the inferior angle,
the arch being connected to the border of the scapula by a thin membrane. When
the arch extends, as it occasionally does, but a short distance, the muscular fibres are
inserted into the scapula itself.
Relations. By their superficial surface, with the integument, and Trapezius,
the, Rhomboideus major, with the Latissimus dorsi. By their deep surface, with
the Serratus posticus superior, posterior scapular artery, part of the Erector spinse,
the Intercostal muscles and ribs.
Nerves. These muscles are supplied by branches from the fifth cervical nerve,
and additional filaments from the deep branches of the cervical plexus are distri-
buted to the Levator anguli scapulae.
222 MUSCLES AND FASCIiE.
Actions. The movements effected by the preceding muscles are numerous, as may
be conceived from their extensive attachment. If the head is fixed, the upper
part of the Trapezius will elevate the point of the shoulder, as in supporting
weights; when the middle and lower fibres are brought into action, partial rotation
of the scapula upon the side of the chest is produced. If the shoulders are fixed
both Trapezii acting together will draw the head directly backwards, or if only
one acts, the head is drawn to the corresponding side.
The Latissimus Dorsi, when it acts upon the humerus, draws it backwards and
downwards, and at the same time rotates it inwards. If the arm is fixed, the
muscle may act in various ways upon the trunk; thus, it may raise the lower ribs
and assist in forcible inspiration, or if both arms are fixed, the two muscles may
conspire with the Abdominal and great Pectoral muscles in drawing the whole
trunk forwards, as in climbing or walking on crutches.
The Levator Anguli Scapulce raises the superior angle of the scapula after it
has been depressed by the Trapezius, whilst the Rhomboid muscles carry the infe-
I'ior angle backwards and upwards, thus producing a slight rotation of the scapula
upon the side of the chest. If the shoulder be fixed, the Levator scapulae may
incline the neck to the corresponding side. The Rhomboid muscles acting together
with the middle and inferior fibres of the Trapezius, will draw the scapula directly
backwards towards the spine.
Third Later.
Serratus Posticus Superior, Serratus Posticus Inferior,
o 1 . ( Splenius Capitis.
bplenius <^ ci -x • r^. Tt
{ Splenius Colli.
Dissection. The third layer of muscles is brought Into view by the entire removal of
the preceding, together with the Latissimus dorsi. To effect this, the Levator anguli
scapulae and Rhomboid muscles should be detached near their insertion, and reflected
upwards, thus exposing the Serratus posticus superior ; the Latissimus dorsi should then
be divided in the middle by a vertical incision carried from its upper to its lower part, and
the two halves of the muscle reflected.
The Serratus Posticus Superior is a thin, flat muscle, irregularly quadrilateral
in form, and situated at the upper and back part of the thorax. It arises by a
thin and broad aponeurosis, from the ligamentum nuchse and from the spinous pro-
cesses of the last ceiwical and two or three upper dorsal vertebrae. Inclining
downwards and outwards, it becomes muscular, and is inserted by four fleshy digi-
tations, into the upper borders of the second, third, fourth^ and fifth ribs, a little
beyond their angles.
Relations. By its superficial surface, with the Trapezius, Rhomboidei, and Ser-
ratus magnus. By its deep surface, with the Splenius, upper part of the Erector
spinae, Intercostal muscles and ribs.
The Serratus Posticus Inferior is situated at the lower part of the dorsal and
upper part of the lumbar regions: it is of an irregularly quadrilateral form,
broader than the preceding, and separated from it by a considerable interval. It
arises by a thin aponeurosis from the spinous processes of the two lower dorsal
and two or three upper lumbar vertebrae, and from the inter-spinous ligaments.
Passing obliquely upwards and outwards, it becomes fleshy, and divides into four
flat digitations, which are inserted into the lower borders of the four lower ribs, a
little beyond their angles.
Relations. By its superficial surface, it is covered by the Latissimus dorsi, with
the aponeurosis of which its own aponeurotic origin is inseparably blended. By
its deep surface, with the posterior aponeurosis of the Transversalis, the Erector
spinae, ribs and Intercostal muscles. Its upper margin is continuous with the ver-
tebral aponeurosis.
The Vertebral Aponeurosis is a thin aponeurotic lamina, extending along the
whole length of the posterior part of the thoracic region, serving to bind down the
Erector spiuEe, and separating it from those muscles which connect the spine to
OF THE BACK.
223
the upper extremity. It consists of longitudinal and ti*ansverse fibres blended
together, forming a thin lamella, which is attached in the median line to the spi-
nous processes of the dorsal vertebrae; externally, to the angles of the ribs; and
below, to the upper border of the Inferior serratus and tendon of the Latissimus
dorsi; above, it passes beneath the Serratus posticus superior, and blends with the
deep fascia of the neck.
The Serratus posticus superior should now be detached from its origin and turned out-
wards, when the Splenius muscle will be brought into view.
The Spleiiius is a broad muscle, situated at the posterior part of the neck and
upper part of the dorsal region. At its origin, it is a single muscle, narrow and
pointed in form; but it soon becomes broader, and divides into two portions, which
have separate insertions. It arises, by tendinous fibres, from the lower half of
the Ligamentum nuchse, from the spinous processes of the last cervical and of the
six upper dorsal vertebrae, and from the supra-spinous ligament. From this
origin, the fleshy fibres proceed obliquely upwards and outwards, forming a broad
flat muscle, which divides as it ascends into two portions, the Splenius capitis and
Splenius colli.
The Splenius capitis is inserted into the mastoid process of the temporal bone,
and into the rough surface on the occipital bone beneath the superior curved line.
The Splenius colli is inserted, by tendinous fasciculi, into the posterior tubercles
of the transverse processes of the three or four upper cervical vertebras.
The Splenius is separated from its fellow of the opposite side by a triangular
interval, in which is seen the Complexus.
Relations. By its superficial surface, with the Trapezius, from which it is sepa-
rated below by the Rhomboidei and the Serratus posticus superior. It is also
covered by the Sterno-mastoid and Levator anguli scapulae. By its deep surface,
with the Spinalis dorsi, Longissimus dorsi, Semi-spinalis colli, Complexus, Trachelo-
mastoid, and Transversalis colli.
Nerves. The Splenius and Superior serratus are supplied from the external
posterior branches of the cervical nerves; the Inferior serratus, from the external
branches of the dorsal nerves.
Actions. The Serrati are respiratory muscles acting in antagonism to each
other. The Serratus posticus superior elevates the ribs; it is, therefore, an inspi-
ratory muscle; while the Serratus inferior draws the lower ribs downwards, and
is a muscle of expiration. This muscle is also probably a tensor of the vertebral
aponeurosis. The Splenii muscles of the two sides, acting together, draw the
head directly backwards, assisting the Trapezius and Complexus; acting sepa-
rately, they draw the head to one or the other side, and slightly rotate it, turning
the face to the same side. They also assist in supporting the head in the erect
position.
Fourth Later.
Sacral and Lumbar Regions. Cervical Region.
Erector Spinte. Cervicalis ascendens.
Dorsal Region. Transversalis cervicis.
Sacro-lumbalis. Trachelo-mastoid.
Musculus accessorius ad sacro-lumbalem. Complexus.
Longissimus dorsi. Biventer cervicis.
Spinalis dorsi. Spinalis cervicis.
Dissection. To expose the muscles of the fourth layer, the Serrati and vertebral aponeu-
rosis should be entirely removed. The Splenius may then be detached by separating its
attachments to the spinous processes, and reflecting it outwards.
The Erector Spince (fig. 1 42), and its prolongations in the dorsal and cervical
regions, fill up the vertebral groove on each side of the spine. They are covered
in the lumbar region by the lumbar aponeurosis; in the dorsal region, by the
Serrati muscles and the vertebral aponeurosis; and in the cervical region, by a
224
MUSCLES AND FASCIiE.
144. — Muscles of the Back. Deep Layers
\ifnt i
MULTIFIUUS SPIN/e
iffmi
1 i^Jiu/inbar V-
l^^Sacrat^
OF THE BACK.
225
layer of cervical fascia continued beneath the Trapezius, This large muscular
and tendinous mass varies in size and structure at different parts of the spine.
In the sacral region, the Erector spinaa is narrow and pointed, and its origin
chiefly tendinous in structure. In the lumbar region, it becomes enlarged, and
forms a large fleshy mass. In the dorsal region, it subdivides into two parts,
which gradually diminish in size as they ascend to be inserted into the vertebra}
and ribs, and are gradually lost in the cervical region, where a number of special
muscles are superadded, which are continued upwards to the head, which they
support upon the spine.
The Erector spinas arises from the sacro-iliac groove, and from the anterior
surface of a very broad and thick tendon, which is attached, internally, to the
spines of the sacrum, to the spinous processes of the lumbar and three lower dorsal
vertebra, and the supra-spinous ligament; externally, to the back part of the inner
lip of the crest of the ilium, and to the series of eminences on the posterior part
of the sacrum, representing the transverse processes, where it blends with the
great sacro-sciatic ligament. The muscular fibres thus arising form a single large
muscular mass, bounded in front by the transverse processes of the lumbar ver-
tebrge, and by the middle lamella of the fascia of the Transversalis muscle. Oppo-
site the last rib, this mass divides into two parts, one external, the Sacro-lumbalis,
the other internal and larger, the Longissimus dorsi.
The Sacro-Lumbalis, the external and smaller portion of the Erector spinae, is
inserted, by a series of separate tendons, into the angles of the six lower ribs. If
this muscle is reflected outwards, it will be seen to be reinforced by a series of
muscular slips, which arise from the angles of the ribs; by means of these the
Sacro-lumbalis is continued upwards, to be connected with the upper ribs, and
with the cervical portion of the spine, forming two additional muscles, the Mus-
culus accessorius and the Cervicalis ascendens.
The Musculus Accessorius ad Sacro-Lumbalem arises by separate flattened
tendons, from the upper margins of the angles of the six lower ribs; these become
muscular, and are finally inserted, by separate tendons, into the angles of the six
upper ribs.
The Cervicalis Ascendens is the continuation of the Sacro-lumbalis upwards
mto the neck: it is situated on the inner side of the tendons of the Accessorius,
arising from the angles of the four or five upper ribs, and is inserted, by a series
of slender tendons, into the posterior tubercles of the transverse processes of the
fourth, fifth, and sixth cervical vertebrae.
Longissimus Dorsi. The inner portion of the Erector spinae, the larger and
longer of the two, has received the name ' Longissimus dorsi.' It arises, with the
Sacro-lumbalis, from the common origin already mentioned. In the lumbar region,
where it is as yet blended with the Sacro-lumbalis, some of the fibres are directed
forwards to be inserted into the posterior surface of the transverse processes of
the lumbar vertebrae their whole length, into the tubercles at the back of the
articular processes, and into the layer of lumbar fascia connected with the apices
of the transverse processes. In the dorsal region, the Longissimus dorsi is inserted,
by long and thin tendons, into the extremities of the transverse processes of all
the dorsal vertebra, and into from seven to eleven ribs between their tubercles
and angles.
This muscle is continued upwards to the cranium and cervical portion of the
spine, by means of two additional slender fasciculi, the Transversalis colli, and
Trachelo-mastoid.
The Transversalis Colli, placed on the inner side of the Longissimus dorsi,
arises, by long thin tendons, from the summit of the transverse processes of the
third, fourth, fifth, and sixth dorsal vertebras, and is inserted, by similar tendons,
into the posterior tubercles of the transverse processes of the five lower cervical.
The Trachelo-Mastoid lies on the inner side of the preceding, between it and
the Complexus muscle, and may be regarded as the. continuation of the Longissimus
dorsi upwards to the head. It arises, by four tendons, from the transverse pro-
226 MUSCLES AND FASCIA.
cesses of the third, fourth, fifth, and sixth dorsal vertebrae, and from the articular
processes of the three or four lower cervical; these joining form a small muscle,
which ascends to be inserted into the posterior margin of the mastoid process,
beneath the Splenius and Sterno-mastoid muscles. This small muscle is almost
always crossed by a tendinous intersection near its insertion into the mastoid
process.
The spinous processes of the upper lumbar and the dorsal vertebra3 are con-
nected together by a series of muscular and tendinous slips, which are intimately
connected with the Longissimus dorsi, forming, in fact, part of this muscle; it is
called the Spinalis dorsi.
The Spinalis Dorsi is situated at the inner side of the Longissimus dorsi. It
arises, by three or four tendons, from the spinous processes of the two upper
lumbar and the two lower dorsal vertebrae: these uniting, form a small muscle,
which is inserted, by separate tendons, into the spinous processes of all the upper
dorsal vertebra?, the number varying from four to eight. It is intimately united
with the Semi- spinalis dorsi, which lies beneath it.
The Spinalis Cervicis is a small muscle, connecting together the spinous pro-
cesses of the cervical vertebrte, and analogous to the Spinalis dorsi in the dorsal
region. This muscle varies considerably in its size, and in its extent of attachment
to the vertebras, not only in different bodies, but on the two sides of the same
body. It usually arises by fleshy or tendinous fibres, varying from two to four in
number, from the spinous processes of the fifth and sixth cervical vertebrae, and
occasionally from the first and second dorsal, and is inserted into the spinous pro-
cess of the axis, and occasionally into the spinous processes of the two vertebrse
below it. This muscle has been found absent in five cases out of twenty-four.
The Complexus is a broad thick muscle, situated at the upper and back part of
the neck, lying beneath the Splenius, the direcfion of which it crosses obliquely
from without inwards. It arises, by a series of tendons, about seven in number,
from the posterior and upper part of the transverse processes of the three upper
dorsal and seventh cervical, and from the articular processes of the three cervical
above this. The tendons uniting form a broad muscle, which is directed obliquely
upwards and inwards, and is inserted into the innermost depression between the
two curved lines of the occipital bone. This muscle, about its middle, is traversed
by a transverse tendinous intersection.
The Biventer Cervicis, is a small fasciculus, situated on the inner side of the pre-
ceding muscle, and in the majority of cases blended with it; it has received its
name from presenting a tendon of considerable length with tAvo fleshy bellies.
It is sometimes described as a separate muscle, arising, by from two to four ten-
dinous slips, from the transverse processes of as many upper dorsal vertebrae, and
is inserted, on the inner side of the Complexus, into the superior curved line of
the occipital bone.
Relations. By their superficial surface, with the Trapezius and Splenius. By
their deep surface, with the Semi-spinalis dorsi and colli and the Recti and Obliqui.
The Biventer cervicis is separated from its fellow of the opposite side by the liga-
mentum nuchje, and the Complexus from the Semi-spinalis colli by the profunda
cervicis artery, the princeps cervicis branch of the occipital, and by the posterior
cervical plexus of nerves.
Nerves. The Erector spinas and its subdivisions in the dorsal region are sup-
plied by the external posterior branches of the lumbar and dorsal nerves. The
Cervicalis ascendens, Transversalis colli, Trachelo-mastoid, and Spinalis cervicis,
by the external posterior branches of the cervical nerves; the Complexus, by the
internal posterior branches of the cervical nerves, the sub-occipital and great
occipital.
OF THE BACK.
Fifth Layer.
Semi-spinalis Uorsi. Extensor Coccygis.
227
Semi-spinulis Colli. Inter-transversalcs.
Multifidus Spina3. Rectus Capitis Posticus Major.
Rotatores Spina3. Rectus Capitis Posticus Minor.
Supra-spinales. Obliquus Superior.
Inter-spinales. Obliquus Inferior.
Dissection. The muscles of the preceding layer must be removed by dividing and turning
aside the Complexus, then detach the Spinalis and Longissimus dorsi from their attach-
ments, and divide the Erector spinas at its connection below to the sacral and lundjar
spines, and turn it outwards. The muscles filling up the interval between the spinous and
transverse processes are then exposed.
The Semi-spinales JIuscles connect together the transverse and spinous pro-
cesses of the vertebrtB, extending from the lower part of the dorsal region to the
upper part of the cervical.
The Semi-spinalis Dorsi consists of a thin, narrow, fleshy fasciculus, interposed
between tendons of considerable length. It arises by a series of small tendons
from the transverse processes of the lower dorsal vertebrfB, from the tenth or
eleventh to the fifth or sixth; these uniting form a small muscular fasciculus,
which subdividing into five or six tendons, is inserted into the spinous j)rocesses
of the four upper dorsal and two lower cervical.
The Semi-spinalis Colli, thicker than the preceding, arises by a series of tendi-
nous and fleshy points from the transverse processes of the four upper dorsal
vertebrae, and is inserted into the spinous processes of the four upper cervical ver-
tebrae, from the axis to the fifth cervical. The fasciculus connected with the axis
is the largest, and chiefly muscular in structure.
Relations. By their superficial surface, from below upwards with the Longis-
simus dorsi. Spinalis dorsi, Splenius, Complexus, the profunda cervicis and princeps
cervicis arteries, and the posterior cervical plexus of nerves. By their deep
surface, with the Multifidus spinae.
The Multifidus Spince consists of a number of fleshy and tendinous fasciculi,
which fill up the groove on either side of the spinous processes of the vertebrae
from the sacrum to the axis. In the sacral region, these fasciculi arise from the
sacral groove, as low down as the fourth sacral foramen, being connected with the '
aponeurosis of origin of the Erector spinse. In the iliac region, from the inner
surface of the posterior superior spine, and posterior sacro-iliac ligaments. In the
lumbar and cervical regions they arise from the articular processes, and in the
dorsal region, from the transverse processes. Each fasciculus, ascending obliquely
upwards and inwards, is inserted into the lamina and whole length of the spinous
process of the vertebra above. These fasciculi vary in length; the most sujDcr-
ficial, the longest, pass from one vertebra to the third or fourth above ; those next in
order pass from one vertebra to the second or third above; whilst the deepest con-
nect two contiguous vertebrae.
Relations. By its superficial surface, with the Longissimus dorsi. Spinalis dorsi,
Semi-spinalis dorsi, and Semi-spinalis colli. By its deep surface, with the laminae
and spinous processes of the vertebrae, and with the Rotatores spinas in the dorsal
region.
The Rotatores Spines are found only in the dorsal region of the spine, beneath
the Multifidus spinae, they are eleven in number on each side. Each muscle,
which is small and somewhat quadrilateral in form, arises from the upper and back
part of the transverse process, and is inserted into the lower border and outer
surface of the lamina of the vertebra above, the fibres extending as far inwards as
the -root of the spinous process. The first is found between the first and second
dorsal, the last, between the eleventh and twelfth. Sometimes the number of these
muscles is diminished by the absence of one or more from the upper or lower end.
The Supra Spinales consist of a series of fleshy bands, which lie on the spi-
nous processes in the cervical region of the spine. -
Q 2
228 MUvSCLES AND FASCIA.
The Inter- S pinoles are short muscular fasciculi, placed in pairs between the
spinous processes of the contiguous vertebrae. In the cervical region they are
most distinct, and consist of six pairs, the first being situated between the axis and
third vertebra, and the last between the last cervical and the first dorsal. In the
dorsal region they are found above, between the first and second vertebras, and
occasionally between the second and third; and below, between the eleventh and
twelfth. In the lumbar region there are four pairs of these muscles in the intervals
between the five lumbar vertebra?. There is also occasionally one in the inter-
spinous space, between the last dorsal and first lumbar, and between the fifth
lumbar and the sacrum.
The Extensor Coccygis is a slender muscular fasciculus, occasionally present,
which extends over the lower part of the posterior surface of the sacrum and
coccyx. It arises by tendinous fibres from the last bone of the sacrum, or first
piece of the coccyx, and passes downwards to be inserted into the lower part of
the coccyx. It is a rudiment of the Extensor muscle of the caudal vertebrfe
present in some animals.
The Inter-Transversales are small muscles placed between the transverse pro-
cesses of the vertebrae. In the cervical region they are most developed, consisting
of two rounded muscular and tendinous fasciculi, which pass between the anterior
and posterior tubercles of the transverse processes of two contiguous vertebras,
being separated from one another by the anterior branch of a cervical nerve,
which lies in the groove between them, and by the vertebral artery and vein. In
this region there are seven pairs of these muscles, the first being between the
atlas and axis, and the last between the seventh cervical and first dorsal vertebrae.
In the dorsal region the Inter-transversales are least developed, consisting chiefly
of rounded tendinous cords in the inter-transverse spaces of the upper dorsal
vertebrae ; but between the transverse processes of the three lower dorsal vertebrae
and the first lumbar, they are muscular in structure. In the lumbar region they
are four in number, and consist of a single muscular layer, which occupies the
entire interspace between the transverse processes of the lowest lumbar vertebrae,
whilst those between the transverse processes of the upper lumbar, are not attached
to more than half the breadth of the process.
The Rectus Capitis Posticus Major, the larger of the two Recti, arises by a
pointed tendinous origin from the spinous process of the axis, and becoming broader
as it ascends, is inserted into the inferior curved line of the occipital bone and the
surface of bone immediately beneath it. As the muscles of the two sides ascend
upwards and outwards, they leave between them a triangular space, in which are
seen the Recti capitis postici minores muscles.
Relations. By its superficial surface, with the Complexus, and at its insertion,
with the Superior oblique. By its deep surface, with the posterior arch of the atlas,
the posterior occipito-atloid ligament, and part of the occipital bone.
The Rectus Capitis Posticus Minor, the smallest of the four muscles in this
region, is of a triangular shape, it arises by a narrow, pointed tendon from the tu-
bercle on the posterior arch of the atlas, and becoming broader as it ascends, is
inserted into the rough surface beneath the inferior curved line, nearly as far as
the foramen magnum, nearer to the middle line than the preceding.
Relations. By its superficial surface, with the Complexus. By its deep sur-
face, with the posterior occipito-atloid ligament.
The Obliquus Inferior, the largest of the two oblique muscles, arises from the
apex of the spinous process of the axis, and forms a thick cylindrical muscle,
which passes almost horizontally outwards, to be inserted into the apex of the
transverse process of the atlas.
Relations. By its superficial surface, with the Complexus, and is crossed by
the posterior branch of the second cervical nerve. By its deep surface, with the
vertebral artery and posterior occipito-atloid ligament.
The Obliquus Superior, narrow below, wide and expanded above, arises by
tendinous fibres from the upper part of the extremity of the transverse process of
OF THE BACK. 229
the atlas, joining with the insertion of the Inferior oblique muBcle, and passing
obliquely upwards and inwards, is inserted into the occipital bone, between the
two curved lines, external to the Complexus. Between the two oblique muscles
and the Rectus posticus major, a triangular interval exists, in which is seen the
vertebral artery and the posterior branch of the sub-occipital nerve.
Relations. By its superficial surface, with the Complexus and Trachelo-mas-
toid. By its deep surface, with the posterior occipito-atloid ligament.
Nerves. The Semi-spinalia dorsi and Rotatores spinse are supplied by the inter-
nal posterior branches of the dorsal nerves. The Semi-spinalis colli, Supra-
spinales, and Inter-spinales, by the internal posterior branches of the cervical
nerves. The Inter- transversales, by the internal posterior branches of the cervi-
cal, dorsal, and lumbar nerves. And the Multifidus spinas, by the same, with the
addition of the internal posterior branches of the sacral nerves. The Recti and
Obliqui muscles are all supplied by the sub-occipital and great occipital nerves.
Actions. The Erector spina3, comprising the Sacro-lumbalis, with its accessory
muscle, the Longissimus dorsi and Spinalis dorsi, serves, as its name implies, to
maintaiB the spine in the erect posture; it also serves to bend the ti'unk back-
wards, when it is required to counter-balance the influence of any weight at the
front of the body, as, for instance, when a heavy weight is suspended from the
neck, or when there is any great abdominal development, as in pregnant women
or in abdominal dropsy; the peculiar gait under such circumstances depends upon
the spine being drawn backwards, by the counter-balancing action of the Erector
spin£e muscles. The continuation of these muscles upwards to the neck and head,
steady and preserve the upright position of these several parts. If the Sacro-
lumbalis and Longissimus dorsi of one side act, they serve to draw down the chest
and spine to the corresponding side. The Musculus acce'ssorius, taking its fixed
point from the cervical vertebrae, elevates those ribs to which it is attached. The
Multifidus spinas act successively upon the different segments of the spine; thus
the lateral parts of the sacrum furnish a fixed point from which the fasciculi of
this muscle act upon the lumbar region; these then become the fixed points for
the fasciculi moving the dorsal region, and so on throughout the entire length of
the spine; it is by the successive contraction and relaxation of the separate fas-
ciculi of this and other muscles, that the spine preserves the erect posture without
the fatigue that would necessarily have existed had this movement been accom-
plished by the action of a single muscle. The Multifidus spinas, besides pre-
serving the erect position of the sjDine, serves to rotate it, so that the front of the
trunk is turned to the side opposite to that from which the muscle acts, this
muscle being assisted in its action by the Obliquus externus abdominis. The
Complexi, the analogues of the Multifidus spinas in the neck, draw the head
directly backwards; if one muscle acts, it draws the head to one side, and rotates
it so that the face is turned to the opposite side. The Rectus capitis posticus mi-
nor and the Superior oblique draw the head backwards, and the latter from the
obliquity in the direction of its fibres, may turn the face to the opposite side. The
Rectus capitis posticus major and the Obliquus inferior, rotate the atlas, and with
it the cranium around the odontoid process, and turn the face to the same side.
Muscles of the Abdomen.
The muscles in this region are, the
Obliquus Externus. Rectus.
Obliquus Internus. Pyramidalis,
Transversalis. Quadratus Lumborum.
Dissection (fig. 145). To dissect the abdominal muscles, a vertical incision should be
made from the ensiform cartilage to the puhes ; a second oblique incision should extend
from the umbilicus upwards and outwards to the outer surface of the chest, as high as the
lower border of the fifth or sixth rib ; and a third, commencing rnidway between the umbi-
licus and pubes, should pass transversely outwards to the antei'ior superior ihac spine, and
along the crest of the ilium as far as its posterior third. The three flaps included between
230
MUSCLES AND FASCItE.
14.5. — Dissection of Abdomen.
these incisions should then be reflected from within outwards, in the direction indicated in
the figure.
The External Oblique Muscle (Obliquus descendens) (fig, 146), so called from
the direction of its fibres, is situated on the lateral and anterior aspects of the
abdomen ; being the largest and the most superficial of the three flat muscles in this
region. It is broad, thin, irregularly quadrilateral in form, its muscular portion
occupying the sides, its aponeurosis the anterior wall of that cavity. It arises, by
eight fleshy digitations, from the external surface and lower borders of the eight
inferior ribs ; these digitations are arranged in an oblique line running downwards
and backwards; the upper ones being attached close to the cartilages of the cor-
resj)onding ribs; the lowest, to the apex of the cartilage of the last rib; the inter-
mediate ones, to the ribs at some distance from their cartilages. The five superior
serrations increase in size from above down-
wards, and are received between corresponding
processes of the Serratus magnus; the three
lower ones diminish in size from above down-
wards, receiving between them corresponding-
processes from the Latissimus dorsi. From
these attachments the fleshy fibres proceed in
various directions. Those from the lowest ribs
pass nearly vertically downwards, to be inserted
into the anterior half of the outer lip of the
crest of the ilium; the middle and upper fibres,
directed downwards and forwards, terminate in
tendinous fibres, which spread out into a broad
aponeurosis. This aponeurosis, joined with that
of the opposite muscle along the median line,
covers the whole of the front of the abdomen:
above, it is connected with the lower border of
the Pectoralis major; below, its fibres are closely
aggregated together, and extend obliquely across
from the anterior superior spine of the ilium to
the spine of the os pubis and the pectineal line.
In the median line, it interlaces with the apo-
neurosis of the opposite muscle, forming the
linea alba, and extends from the ensiforra car-
tilage to the symj)hysis pubis.
That portion of the aponeurosis which extends between the anterior superior
spine of the ilium and the spine of the os pubis is a broad band, folded inwards, and
continuous below with the fascia lata; it is called Pouparfs ligament. The por-
tion which is reflected from Poupart's ligament backwards and inwards into the
pectineal line, is called Gimhernat's ligament.
In the aponeurosis of the External oblique, immediately above the crest of the
OS pubis, is a triangular opening, the external abdominal ring, formed by a splitting
of the fibres of the aponeurosis in this situation ; it serves for the transmission of
the spermatic cord in the male, and the round ligament in the female. This opening
is directed obliquely upwards and outwards, and corresponds with the course of
the fibres of the aponeurosis. It is bounded below by the crest of the os pubis;
above, by some curved fibres, which pass across the aponeurosis at the upper
angle of the ring so as to increase its strength; and on either side, by the margins
of the aponeurosis, which are called the pillars of the ring. Of these, the external,
which is, at the same time inferior, from the obliquity of its direction, is inserted
into the spine of the os pubis. The internal, or superior pillarjvbeing attached to
the front of the symphysis pubis, interlaces with the corresponding fibres of the
opposite muscle. To the margins of the pillars of the external abdominal ring is
attached an exceedingly thin and delicate fascia, which is prolonged down over
the external surface of the cord and testis. This has received the name of inter-
3.
of \
iMC'JINAlV\
HERNIA
OF THE ABDOMEN.
231
columnar fascia from its attachment to the pillai-s of the ring. It has also re-
ceived the name of external spermatic fascia, from being tlie most external of
the fascia3 whicli cover tlie spermatic cord.
Relations. By its external surface, with the superficial fascia, superficial
epigastric and circumflexa ilii vessels, and some cutaneous nerves. By its internal
surface, with the Internal oblique, the lower part of the eight inferior ribs and Inter-
costal muscles, the cremaster, the spermatic cord in the male, and round ligament in
the female. Its posterior border is occasionally overlapped by the Latissimus dorsi;
sometimes an interval exists between the two muscles, in which is seen a portion
of the Internal oblique.
146, — The External Oblique Muscle.
^lit.Abdo7iu>i(il JRirLq-'r —
Clmiernat's Ligl—I—
I
Dissection. The External oblique should now be detached by dividing it across, just in
front of its attachment to the ribs, as far as its posterior border, and by separating it
below from the crest of the ilium as far as the spine ; the muscle should then be carefully
separated from the Internal oblique, which lies beneath, and turned towards the opposite
side. '
The Internal Oblique Muscle (fig. 147) (Obliquus ascendens), thinner and
23:
MUSCLES AND FASCIA.
smaller than the preceding, beneath which it lies, is of an irregularly quadrilateral
form, and situated at the anterior lateral and posterior parts of the abdomen. It
arises, by fleshy fibres, from the outer half of Poupart's ligament, being attached to
the groove on its upper surface; from the anterior two-thirds of the middle lip of
the crest of the ilium, and from the lumbar fascia. From this origin, the fibres
diverge in different directions. Those from Poupart's ligament, few in number
and paler in colour than the rest, arch downwards and inwards across the sper-
matic cord, to be inserted, conjointly with those of the Transversalis, into the
crest of the os pubis and pectineal line, to the extent of half an inch, forming the
conjoined tendon of the Internal oblique and Transversalis; those from the anterior
superior iliac spine are horizontal in their direction; whilst those which arise from
the front part of the crest of the ilium pass obliquely upwards and inwards,
and terminate in an aponeurosis, which is continued forwards to the linea alba;
the most posterior fibres ascend almost vertically upwards, to be inserted into the
147. — The Internal Oblique Muscle.
Conjoined fene/on—r-
L
CREMASTER
lower borders of the cartilages of the four lower ribs, being continuous with the
internal intercostal muscles.
The conjoined tendon of the Internal oblique and Transversalis is inserted into
the crest of the os pubis and pectineal line immediately behind the external abdo-
minal ring, serving to protect what Avould otherwise be a weak point in the
abdomen. Sometimes this tendon is insufiicient to resist the pressure from within,
and is carried forward in front of the protrusion through the externf.l ring, forming-
one of the coverings of direct inguinal hernia.
OF THE ABDOMEN.
233
The aponeurosis of the Internal oblique is continued forward to the middle line
of the abdomen, where it joins with the aponeurosis of the opposite muscle at the
linea alba, and extends from the margin of the thorax to the pubes. At the
outer margin of the sheath of the Rectus muscle, for the upper three-fourths of its
extent, this aponeurosis divides into two lamellas, which pass, one in front and the
other behind it, enclosing it in a kind of sheath, and reuniting on its inner border
at the linea alba: the anterior layer is blended with the aponeurosis of the
External oblique muscle; the posterior layer with that of the Transversalis.
Along the lower fourth, the aponeurosis passes altogether in front of the Rectus
without any separation.
Relations. By its external surface, with the External oblique, Latissimus dorsi,
spermatic cord, and external ring. By its internal surface, with the Transversalis
muscle, fascia transversalis, internal ring, and spermatic cord. Its lower border
forms the upper boundary of the spermatic canal.
Dissection. The Internal oblique should now be detached in order to expose the Trans-
versalis muscle beneath. This may be efiected by dividing the muscle, above, at its
attachment to the ribs ; below, at its connexion with Poupart's ligament and the crest of
the ilium ; and behind, by a vertical incision extending from the last rib to the crest of
the ilium. The muscle should previously be made tense by drawing upon it with the
lingers of the left hand, and if its division is carefully effected, the cellular interval between
it and the Transversalis, as weU as the direction of the fibres of the latter muscle, will
afford a clear guide to their separation ; along the crest of the ilium the circumflex ilii
vessels are interposed between them, and form an important aid in separating them. The
muscle should then be thrown forwards towards the linea alba.
The Transversalis muscle (fig. 148), so called from the direction of its fibres,
is the most internal flat muscle of the abdomen, being placed immediately beneath
the Internal Oblique. It arises by fleshy fibres from the outer third of Poupart's
ligament, from the inner lip of the crest of the ilium, its anterior two-thirds, from
the inner surface of the cartilages of the six lower ribs, interdigitating with the
Diaphragm, and by a broad aponeurosis from the spinous and transverse processes
of the lumbar vertebrae. The lower fibres curve downwards, and are inserted to-
gether with those of the Internal oblique, into the crest of the os pubis and pec-
tineal line, forming what was before mentioned as the conjoined tendon of these
muscles. Throughout the rest of its extent the fibres pass horizontally inwards,
and near the outer margin of the Rectus, terminate in an aponeurosis, which is in-
serted into the linea alba; its upper three-fourths passing behind the Rectus
muscle, blending with the posterior lamella of the Internal oblique; its lower
fourth passing in front of the Rectus.
Relations. By its external surface, with the Internal oblique, the inner sur-
faces of the lower ribs, and Internal intercostal muscles. By its internal surface,
it is lined by the fascia transversalis, which separates it from the peritoneum. Its
lower border forms the upper boundary of the spermatic canal.
Lumbar Fascia (fig. 149). The vertebral aponeurosis of the Transversalis divides
into three layers, an anterior, very thin, which is attached to the front part of
the apices of the transverse processes of the lumbar vertebrae, and, above, to the
lower margin of the last rib, forming the ligamentum arcuatum externum; a mid-
dle layer, much sti-onger, which is attached to the apices of the transverse processes;
and a posterior layer, attached to the apices of the spinous processes. Between the
anterior and middle layers is situated the Quadratus lumborum, between the middle
and posterior, the Erector spinae. The posterior lamella of this aponeurosis
receives the attachment of the Internal oblique; it is also blended with the apo-
neurosis of the Serratus posticus inferior and with that of the Latissimus dorsi,
forming the Lumbar fascia; the two anterior layers are connected solely with the
Transversalis.
Dissection. To expose the Rectus muscle, its sheath should be opened by a vertical inci-
sion extending from the margin of the thorax to the piibes, the two portions should then
be reflected from the surface of the muscle, which is easily effected, excepting at the linese
transversae, where so close an adhesion exists, that the greatest care is requisite in sepa-
234
MUSCLES AND FASCIA.
rating them. The outer edge of the muscle should now be raised, when the posterior
layer of the sheath will be seen. By dividing the muscle in the centre, and turning its
lower part downwards, the point where the posterior waU of the sheath terminates in a
thin curved margin will be seen.
The Rectus Abdominis is a long, flat muscle, which extends along the w^hole
length of the anterior wall of the abdomen, being separated from its fellow of the
opposite side by the linea alba. It is much broader above than below, and
arises by two tendons, the external or larger being attached to the crest of the
148. — The Transversalis, Kectus, and Pyramidalis Muscles.
I m e a
OS pubis; the internal, smaller portion, interlacing with its fellow of the opposite
side, and being connected with the ligaments covering the symphysis pubis. The
fibres ascend vertically upwards, and the muscle becoming broader and thinner
at its upper part, is inserted by three portions of unequal size into the cartilages
of the fifth, sixth, and seventh ribs. Some fibres are also occasionally connected
with the costo-xiphoid ligaments, and side of the ensifoi-m cartilage.
OF THE ABDOMEN.
235
The Rectus muscle is traversed by 11 series of tendinous intersections, which
vary from two io five in number, and have received the name lineaa transversoe.
One of these is usually situated opposite the umbilicus, and two above that point;
of these, one corresponds to the ensiform cartilage, and the other, to the interval
between the ensiform cartilage und the umbilicus; there is occasionally one below
the umbilicus. These intersections pass transversely or obliquely across the mus-
cle in a zigzag course; they rarely extend completely through its substance, some-
times pass only half way across it, and are intimately adherent to the sheath in
which the muscle is enclosed.
The Rectus is enclosed in a sheath (fig. 149) formed by the aponeuroses of the
Oblique and Transversalis muscles, which are arranged in the following manner.
When the aponeurosis of the Internal oblique arrives at the margin of the Rectus,
it divides into two lamellae, one of which passes in front of the Rectus, blending
with the aponeurosis of the Extei'nal oblique; the other, behind it, blending with
the aponeurosis of the Transversalis; and these, joining again at its inner border,
are inserted into the linea alba. This arrangement of the fascia exists along the
149. — A Transverse Section of the Abdomen in the Lumbar Region.
upper three-fourths of this muscle; at the commencement of the loAver fourth,
the posterior wall of the sheath terminates in a thin curved margin, the concavity
of which looks downwards towards the pubes; the aponeuroses of all three
muscles passing in front of the Rectus without any separation. The Rectus
muscle in the situation where its sheath is deficient, is separated from the perito-
neum by the transversalis fascia.
The Pyramidalis is a small muscle, triangular in form, situated at the lower
part of the abdomen, one on each side of the linea alba. It arises by tendinous
fibres from the front of the OS pubis and anterior pubic ligament; the fleshy portion
of the muscle passes upwards, diminishing in size as it ascends, and terminates by
a pointed extremity, which is inserted into the linea alba, midway between the
umbilicus and the os pubis. It rests against the lower part of the front of the Rec-
tus, and is contained in the same sheath with that muscle. This muscle is some-
times found wanting on one or both sides; the lower end of the Rectus then
becomes proportionally increased in size. Occasionally it has been found double
on one side, or the muscles of the two sides are of unequal size. Sometimes its
length exceeds that stated above.
The Quadratus Lumhorum is situated in the lumbar region of the spine,
it is irregularly quadrilateral in shape, broader below than above, and consists
of two portions. One portion arises by aponeurotic fibres from the ilio-
lumbar ligament, and the adjacent portion of the crest of the ilium for about two
236 MUSCLES AND FASCIiBL
inches, and is inserted into the lower border of tlie last rib, about half its length,
and by four small tendons, into the apices of the transverse processes of the third,
fourth, and fifth lumbar vertebrae. The other portion of the muscle, situated
anterior to the preceding, arises from the upper borders of the transverse processes
of the third, fourth, and fifth lumbar vertebrae, and is inserted into the lower margin
of the last rib. The Quadratus lumborum is contained in a sheath formed by
the anterior and middle lamellae of the vertebral aponeurosis of the Transversalis.
Nerves. All the abdominal muscles are supplied by the lower intercostal, ilio-
hypo-gastric, and ilio-inguinal nerves, excepting the Quadratus lumborum, which
receives filaments from the anterior primary branches of the lumbar nerves.
In the description of the abdominal muscles, mention has frequently been made
of the linea alba, line^e semilunares, lineae transversas; when the dissection of these
muscles is completed, these structures should be examined.
The Linea Alba is a tendinous raphe or cord seen along the middle line of the
abdomen, extending from the ensiform cartilage to the symphysis pubis. It is
placed between the inner borders of the Recti muscles, and formed by the blending
of the anterior aponeuroses of the Oblique and Transversalis muscles. It is nar-
row below, corresponding to the narrow interval existing between the Recti, but
broader above, as these muscles diverge from one another in their ascent, be-
coming of considerable breadth after great distension of the abdomen from preg-
nancy or ascites. It presents numerous apertures for the passage of vessels and
nerves; the largest of these is the umbilicus, which in the foetus transmits the
umbilical vessels, but in the adult is obliterated, the cicatrix being stronger than
the neighbouring parts; hence the occurrence of umbilical hernia in the adult
above the umbilicus, whilst in the foetus it occvirs at the umbilicus. The
linea alba is in relation, in front, with the integument to which it is adherent,
especially at the umbilicus; behind, it is separated from the peritoneum by the
transversalis fascia; and below, by the urachus, and the bladder, when that organ
is distended.
The LinecB Semilunares are two curved tendinous lines, placed one on each
side of, and a little external to the linea alba. Each extends from the cartilage of
the eighth rib to the pubes, and corresponds with the outer border of the Rectus
muscle. They are formed by the aponeurosis of the Internal oblique at its point
of division to enclose the Rectus.
The Linece Transverse^ are three or four narrow transverse lines which inter-
sect the Rectus muscle as already mentioned, they connect the lineae semilunares
with the linea alba.
Actions. The abdominal muscles perform a three-fold action.
When the pelvis and thorax are fixed, they can compress the abdominal viscera,
by constricting the cavity of the abdomen, in which action they are materially
assisted by the descent of the diaphragm. By these means, the foetus is expelled
from the uterus, the fasces from the rectum, the urine from the bladder, and the
ingesta from the stomach in vomiting.
If the spine be fixed, these muscles compress the lower part of the thorax, ma-
terially assisting in the process of expiration. If the spine be not fixed, the thorax
is bent directly forward, if the muscles of both sides act, or to either side if they act
alternately, rotation of the trunk at the same time taking place to the opposite side.
If the thorax be fixed, these muscles act upon the pelvis, as in climbing, when
the pelvis is drawn directly upwards, or to one or the other side. The Recti
muscles may draw the pelvis forwards, and flex it upon the vertebral column. The
Pyramidales are tensors of the linea alba.
Muscles and Fascia of the Thorax.
The muscles exclusively connected with the bones in this region are few in
number. They are the
Intercostales Extei-ni. lufra-Costales,
Intercostales Interni. Triangularis vSterni.
Levatores Costarum.
OF THE THORAX. 237
Intercostal Fascice. A thin but firm layer of fascia covers the outer surface of
the External intercostal and the inner surface of the Internal intercostal muscles;
and a third layer, more delicate, is interposed between these two planes of mus-
cular fibres. These are the intercostal fascise; they are best marked in those
situations where the muscular fibres are deficient, as between the External inter-
costal muscles and sternum, in front; and between the Internal intercostals and
spine, behind.
The Intercostal Muscles are two thin planes of muscular and tendinous struc-
ture, placed one over the other, filling up the intercostal spaces, and being directed
obliquely between the margins of the adjacent ribs. These two planes have re-
ceived the name 'external' and 'internal,' from the position they bear to one an-
other.
The External Intercostals are eleven in number on each side, being attached to
the adjacent margins of each pair of ribs, and extending from the tubercles of the
ribs, behind, to the commencement of the cartilages of the ribs, in front, where
they terminate in a thin membranous aponeurosis, which is continued forwards to
the sternum. They arise from the outer lip of the groove on the lower border of
each rib, and are inserted into the upper border of the rib below. In the two
lowest spaces they extend to the end of the ribs. Their fibres are directed
obliquely downwards and forwards, in a similar direction with those of the Exter-
nal oblique muscle of the abdomen. They are thicker than the Internal inter-
costals.
Relations. The External intercostals, by their outer surface, are covered by
the muscles which immediately invest the chest, viz., the Pectoralis major and
minor, Serratus magnus, Ehomboideus major, Serratus posticus superior and infe-
rior, Scalenus posticus, Sacro-lumbalis and Longissimus dorsi, Cervicalis ascendens,
Transversalis colli, Levatores costarum, and the Obliquus externus abdominis. By
their internal surface, they are in relation with a thin layer of fascia, which
separates them from the intercostal vessels and nerve, the Internal intercostal mus-
cles, and, behind, from the pleura.
The Internal Intercostals, also eleven in number on each side, are placed on
the inner surface of the preceding, commencing anteriorly at the sternum, in the
interspaces between the cartilages of the true ribs, and from the anterior extre-
mities of the cartilages of the false ribs; and extend backwards as far as the
angles of the ribs, where they are continued to the vertebral column by a thin
aponeurosis. They arise from the inner lip of the groove on the lower border of
each rib, as well as from the corresponding costal cartilage, and are inserted into
the upper border of the rib below. Their fibres are directed obliquely downwards
and backwards, decussating with the fibres of the preceding.
Relations. By their external surface, with the External intercostals, and the
intercostal vessels and nerves. By their internal surface, with the pleura costalis.
Triangularis sterni, and Diaphragm.
The Intercostal muscles consist of muscular and tendinous fibres, the latter
being long and more numerous than the former; hence these spaces present very
considerable strength, to which their crossing materially contributes.
The Infra- Co stales consist of muscular and aponeurotic fasciculi, which vary
in number and length; they arise from the inner surface of one rib, and are in-
serted into the inner surface of the first, second, or third rib below. Their direc-
tion is most usually oblique, like the Internal intercostals. They are most frequent
between the lower ribs.
The Triangularis Sterni is a thin plane of muscular and tendinous fibres,
situated upon the inner wall of the front of the chest. It arises from the lower
pari of the side of the sternum, from the inner surface of the ensiform cartilage,
and from the sternal ends of the costal cartilages of the three or four lower true
ribs. Its fibres diverge upwards and outwards, to be inserted by fleshy digitations
into the lower border and inner surfaces of the costal cartilages of the second,
third, fourth, and fifth ribs. The lowest fibres of this muscle are horizontal in
238 MUSCLES AND FASCIA.
their direction, and continuous with those of the Transversalis; those which suc-
ceed are oblique, whilst the supei'ior fibres are almost vertical. This muscle varies
much in its attachment, not only in different bodies, but on opposite sides of the
same body.
Relations. In front yfith the sternum, ensiform cartilage, the costal cartilages,
the Internal intercostal muscles, and internal mammary vessels. Behind, with
the pleura, pericardium, and anterior mediastinum.
The Levatores Costarum, twelve in number on each side, are small tendinous
and fleshy bundles, which arise from the extremities of the transverse processes
of the dorsal vertebrae, and passing obliquely downwards and outwards, are in-
serted into the upper rough surface of the rib below them, between the tubercle
and the angle. That for the first rib arises from the transverse process of the last
cervical vertebra, and that for the last from the eleventh dorsal. The Inferior
levatores divide into two parts, one being inserted as above described, the other
fasciculus passing downwards to the second rib below their origin; thus each of
the lower ribs receives fibres from the transverse processes of tAvo vertebras.
Nerves. The muscles of this group are supplied by the intercostal nerves.
. Actions. The Intercostals are the chief agents in the movement of the ribs in
ordinary respiration. The External intercostals raise the ribs, especially their fore
part, and so increase the capacity of the chest from before backwards; at the same
time they evert their lower borders, and so enlarge the thoracic cavity transversely.
The Internal intercostals, at the side of the thorax, depress the ribs, and invert
their lower borders, and so diminish the thoracic cavity; but at the fore part of
the chest these muscles assist the External intercostals in raising the cartilages.
The Levatores Costarum assist the external intercostals in raising the ribs. The
Triangularis sterni draws down the costal cartilages; it is therefore an expiratory
muscle.
Diaphragmatic Region.
Diaphragm.
The Diaphragm {Aiacfipdaaco, to separate two parts) (fig. 150) is a thin mus-
culo-fibrous septum, placed obliquely at the junction of the upper with the lower
two-thirds of the trunk, and separating the thorax fi'om the abdomen, forming the
floor of the former cavity and the roof of the latter. It is elliptical, its longest
diameter being from side to side, somewhat fan-shaped, the broad elliptical portion
being horizontal, the narrow part, which represents the handle, being vertical, and
joined at right angles with the former. It is from this circumstance that some
anatomists describe it as consisting of two portions, the upper or great muscle of
the diaphragm, and the lower or lesser muscle. This muscle arises from the
whole of the internal circumference of the thorax, being attached, in front, by
fleshy fibres to the ensiform cartilage; on either side, to the inner surface of the
cartilages and bony portions of the six or seven inferior ribs, interdigitating with
the Transversalis; and behind, to the ligamentum arcuatum externum and in-
ternum. The fibres from these sources vary in length; those arising from the
ensiform appendix 'are very short and occasionally aponeurotic; but those from the
ligamenta arcuata, and more especially those from the ribs at the side of the
chest, are the longest, describe well marked curves as they ascend, forming an
arch on each side with the concavity downwards, this concavity being deeper on
the right than on the left side. These fibres converge, to be inserted into the
circumference of the central tendon. Between the sides of the muscular slip
from the ensiform appendix and the cartilage of the adjoining rib, the fibres of the
diaphragm are deficient, the interval being filled by areolar tissue, covered on the
thoracic side by the pleurae, on the abdominal by the peritoneum. This is, con-
sequently, a weak point, and a portion of the contents of the abdomen may pro-
trude into the chest, forming phrenic or diaphragmatic hernia, or a collection of
pus in the mediastinum may descend through it so as to point at the epigastrium.
DIAPHRAGMATIC REGION.
239
The Liganientum Arcuatum Internum is a tendinous ai'ch, thrown across the
upper part of the Psoas magnus muscle, on each side of the spine. It arises from
the outer side of the body of the first, and occasionally from the second lumljar
vertebra, being continuous with the outer side of the tendon of the correspondino-
crus, and, arching across the Psoas muscle, is attached to the front of the trans-
verse process of the second lumbar vertebra.
The Ligamentum Arcuatum Externum is the thickened upper margin of the
anterior lamella of the transversalis fascia; it arches across the upper part of the
Quadratus lumborum, being attached by one extremity to the front of the trans-
verse process of the second lumbar vertebra, and by the other to the apex and
lower margin of the last rib.
150. — The Diaphragm. Under Surface.
Ojtenir>5 J"
Zesscr
To the spine the Diaphragm is connected by two crura, which are situated on
the bodies of the lumbar vertebrae, one on each side of the aorta. The crura at
their origin are tendinous in structure; the right crus, larger and longer than the
left, arising from the anterior surface of the bodies and intervertebral substances
of the second, third, and fourth lumbar vertebrae; the left from the second and
thii'd; and both blending with the anterior common ligament of the spine. A
tendinous arch is thrown across the front of the vertebral column, from the
tendon of one crus to that of the other, beneath which passes the aorta, vena
azygos major, and thoracic duct. The tendons terminate in two large fleshy bellies,
which, with the tendinous portions above alluded to, are called the crura, or
pillars of the diaphragm. The outer fasciculi of the two crura are directed up-
wards and outwards to the central tendon, but the inner fasciculi decussate in front
of the aorta, and then diverge, so as to surround the ossophagus before ending in
240 MUSCLES AND FASCIA.
the tendinous centre. The most anterior and larger of these fasciculi is formed by
the right crus.
The Central or Cordiform Tendon of the Diaphragm is a thin tendinous aponeu-
rosis, situated at the centre of the vault of this muscle, immediately beneath the
pericardium, with which its circumference is blended in adults. It is shaped
somewhat like a trefoil leaf, consisting of three divisions, or leaflets, separated
from one another by slight indentations. The right leaflet is the largest; the
middle one, directed towards the ensiform cartilage, the next in size; and the left
the smallest. In structure, it is composed of several planes of fibres, which inter-
sect one another at various angles, and unite into straight or curved bundles, an
arrangement which afibrds additional strength to the tendon.
The Openings connected with the Diaphragm are three large and several
smaller apertures. The former are the aortic, oesophageal, and the opening for
the vena cava.
The Aortic Opening is the lowest and the most posterior of the three large
apertures connected Avith this muscle. It is situated in the middle line, im-
mediately in front of the bodies of the vertebrte. It is an osseo-aponeurotic
aperture, formed by a tendinous arch throAvn across the front of the bodies of the
vertebrse, from the crus on one side to that on the other, and transmits the aorta,
vena azygos major, thoracic duct, and occasionally the left sympathetic nerve.
The Oesophageal Opening, elliptical in form, muscular in structure, and formed
by the two crura, is placed higher, and, at the same time, anterior, and a little to
the left of the preceding. It transmits the oesophagus and pneumogastric nerves.
The anterior margin of this aperture is occasionally tendinous, being formed by
the margin of the central tendon.
The Opening for the Vena Cava is situated the highest; it is quadrilateral in
form, tendinous in structure, and placed at th6 junction of the right and middle
leaflets of the central tendon, its margins being bounded by four bundles of tendi-
nous fibres, which meet at right angles.
The Right Crus transmits the sympathetic and the greater and lesser splanchnic
nerves of the right side; the left crus, the greater and lesser splanchnic nerves of
the left side, and the vena azygos minor.
The Serous Membranes in relation with the Diaphragm are four in number;
three lining its upper or thoracic surface, one its abdominal. The three serous
membranes on its upper surface are the pleura on either side, and the serous layer
of the pericardium, which covers the upper surface of the tendinous centre. The
serous membrane covering its under surface is a portion of the general peritoneal
membrane of the abdominal cavity.
Peculiarities. The portion of the muscle described as arising from the last rib is
occasionally aponeurotic in structure. The sternal attachment of the muscle is
sometimes partially or entirely deficient.
Relations. Its upper or thoracic surface is convex on each side, and corresponds
with the pleura and lungs, more flattened at the centre where it supports the heart.
The convexity of this surface is greater on the right than on the left side, reaching
in the former situation as high as the junction of the fifth rib with the sternum,
and in the latter as high as the sixth rib. It reaches much higher in the foetus
than in the adult.
Its under or abdominal surface is concave, more so on the right side, where it
is in relation with the convex surface of the liver, than on the left, where it cor-
responds to the spleen and great end of the stomach behind; it is also in relation
with the kidneys, supra-renal capsules, transverse portion of the duodenum, pan-
creas, and the solar plexus.
Nerves. The Diaphragm is supplied by the phrenic nerves.
Actions. The Diaphragm is the most important inspiratory muscle, being the
only one brought into action in tranquil respiration. During inspiration, when
the fibres of the Diaphragm contract, the muscle descends, forming an inclined
plane, which extends from the ensiform cartilage to the tenth rib. During this
OF THE UPPER EXTREMITY.
241
action, the cavity of the thorax is enlarged considerably from above downwards,
and the abdominal viscera are pushed into the lower and fore part of the abdomen,
which is much diminished in size. If the abdominal muscles and Diaphragm act
together, the viscera are compressed and forced to the lower part of the abdominal
cavity, as in most expulsory efforts, which are usually accompanied by a deep
inspiration. During expiration, when the Diaphragm is relaxed, the muscle is
convex, encroaching considerably on the cavity of the chest, particularly at the
sides, its upper border, in a forced expiration, being on a level with the lower
border of the fourth rib on the right side, and with the fifth on the left. During
the action of the Diaphragm the oesophagus is compressed, the aperture through
which it passes being chiefly muscular; the apertures for the vena cava and aorta
are also compressed, but only to a very trifling extent, as the openings for the
passage of these vessels are completely tendinous. Hiccough and sobbing are the
result of spasmodic contraction of this muscle; and laughing and crying are pro-
duced by its rapid alternation of contraction and relaxation, combined with
laryngeal and facial movements.
MUSCLES AND FASCIA OF THE UPPER EXTREMITY.
The Muscles of the Upper Extremity are divisible into groups, corresponding
with the different regions of the limb.
Anterior Thoracic Region.
Pectoralis major.
Pectoralis minor.
Subclavius.
Lateral Thoracic Region.
Serratus magnus.
Acromial Region.
Deltoid.
Anterior Scapular Region.
Subscapularis.
Posterior Scapular Region.
Supra-spinatus.
Infra-spinatus.
Teres minor.
Teres major.
Anterior Humeral Region.
Coraco-brachialis.
Biceps.
Brachialis anticus.
Posterior Humeral Region.
Triceps.
Sub-anconeus.
Anterior Brachial Region.
Pronator radii teres.
Flexor carpi radialis.
Palmaris longus.
I Flexor carpi ulnaris.
.Flexor sublimis digitorum.
r^ ;h' j Flexor profundus digitorum.
S ^ \ Flexor longus pollicis.
^ \A \ Pronator quadratus.
Radial Region.
Supinator longus.
Extensor carpi radialis longior.
Extensor carpi radialis brevior.
Posterior Brachial Region.
( Extensor communis digitorum.
I Extensor minimi digiti.
I Extensor carpi ulnaris.
I Anconeus.
I Supinator brevis.
Extensor ossis metacarpi pollicis.
Extensor primi internodii pollicis.
I Extensor secundi internodii pollicis.
I Extensor indicis.
ce
<D
u
>-.
©
1:3
5
k1
in
Ph
' s
Hi
Muscles of the Hand.
Radial Region,
Abductor pollicis.
Flexor ossis metacarpi pollicis (opponens).
Flexor brevis pollicis.
Adductor pollicis.
Ulnar Region.
Palmaris brevis.
Abductor minimi digiti.
Flexor brevis minimi digiti.
Flexor ossis metacarpi minimi digiti.
Palmar Region.
Lumbricales.
Interossei palmares.
Interossei dorsales.
242
MUSCLES AND FASCIA.
3.D Lsseetbon of
SHOULDER & ARM
2.BEIMDo/'ELB0\M
'^r
FORE-ARIV!
Dissection of Pectoral Region and Axilla (fig. 151). The arm being drawn away from
the side nearly at right angles with the trunk, and rotated outwards, a vertical incision
should be made through the integu-
ment in the median line of the chest, 1 5 1 . — Dissection of Upper Extremity,
from the upper to the lower part
of the sternum; a second incision
should be carried along the lower
border of the Pectoral muscle, from
the ensiform cartilage to the outer
side of the axilla ; a third, from the
sternum along the clavicle, as far as
its centre ; and a fourth, from the
middle of the clavicle obliquely
downwards, along the interspace be-
tween the Pectoral and Deltoid
muscles, as low as the fold of the
armpit. The flap of integument
may then be dissected off in the
direction indicated in the figure,
but not entirely removed, as it
should be replaced on completing
the dissection. If a transverse in-
cision is now made from the lower
end of the sternum to the side of
the chest, as far as the posterior
fold of the armpit, and the integu-
ment reflected outwards, the axillai-y
space will be more completely ex-
posed.
Fascia OF THE Thorax. / , \ r b^. ,v,^uAR,r.
c \ t^ \(5, PALM ^ HAND
The Superficial Fascia of the
thoracic region is a loose cellulo-
fibrous layer, continuous v^itli
the superficial fascia of the neck
and upper extremity above, and
of the abdomen below; oppo-
site the mamma it subdivides into two layers, one of which passes in front, and
the other behind this gland; and from both of these layers numerous septa pass
into its substance, supporting its various lobes: from the anterior layer, fibrous
processes pass forward to the integument and nipple, enclosing in their areolae
masses of fat. These processes were called by Sir A. Cooper, the ligamenta
suspensoria, from the support they afford to the gland in this situation. On
removing the superficial fascia, the deep fascia of the thoracic region is exposed:
it is a thin aponeurotic lamina, covering in the outer surface of the great Pectoral
muscle, and sending numerous prolongations between its fasciculi: it is attached,
in the middle line, to the front of the sternum, and above to the clavicle: it is
very thin over the upper part of the muscle, somewhat thicker in the interval
between the Pectoralis major and Latissimus dorsi, where it closes in the axillary
space, and divides at the margin of the latter muscle into two layers, one of which
passes in front and the other behind it; these proceed as far as the spinous pro-
cesses of the dorsal vertebrEe, to w^hich they are attached. At the lower part of
the thoracic region this fascia is well developed, and is continuous with the fibrous
sheath of the Recti muscles.
Anterior Thoracic Region.
Pectoralis Major.
Pectoralis Minor.
Subclavius.
The Pectoralis Major (fig. 152) is a broad, thick, triangular muscle, situated at
the upper and anterior part of the chest, in front of the axilla. It arises, by short
tendinous fibres, from the entire bi'eadth of the anterior border of the clavicle, its
ANTERIOR THORACIC REGION.
243
sternal half or two-thirds, from one half the breadth of the anterior surface of the
sternum, as low down as the attachment of the cartilage of the sixth or seventh
rib, its origin consisting of aponeurotic fibres, which intersect with those of the
opposite muscle: it also arises from the cartilages of all the true ribs, and from
the aponeurosis of the External oblique muscle of the abdomen. The fibres from
this extensive origin converge tOAvards its insertion, giving to the muscle a radi-
ated appearance. Those fibres which arise from the clavicle pass obliquely down-
152. — Muscles of the Chest and Front of the Arm. Superncial View.
wards and outv/ards, and are usually separated from the rest by a cellular ui-
terval, those from the lower part of the sternum and the cartilages of the lower
true ribs pass upwards and outwards; whilst the middle fibres pass horizontally.
As these three sets of fibres converge, they are so disposed that the upper overlap
the middle, and the middle the lower portion, the fibres of the lower portion being
folded backwards upon themselves; so that those fibres which are lowest in front,
become highest at their point of insertion. They all terminate in a flat tendon,
about two inches broad, which is inserted into the anterior lip of the bicipital
R 2
244 MUSCLES AND FASCIiE.
groove of the humerus. This tendon consists of two laminae, placed one in front
of the other, and usually blended together below. The anterior, the thicker, receives
the clavicular and upper half of the sternal portion of the muscle; the posterior
layer receiving the attachment of the lower half of the sternal portion. A pecu-
liarity resulting from this arrangement is, that the fibres of the upper and middle
portions of the muscle are inserted into the lower part of the bicipital ridge, those
of the lower portion into the upper part. The tendon of the Pectoralis major,
at its insertion, is connected with that of the Deltoid, and from its borders an
expansion is given off above to the head of the humerus below to the fascia of
the arm.
Relations. By its anterior surface, with the Platysraa myoides, the mammary
gland, the superficial fascia, and integument. By its posterior surface : its thoracic
portion, with the sternum, the ribs and costal cartilages, the Subclavius, Pectoralis
minor, Serratus magnus, and the Intercostals; by its axillary portion, it forms the
anterior wall of the axillary space, and is in relation with the axillary vessels and
nerves. By its outer border, it lies parallel with the Deltoid, from which it is
separated by the cephalic vein and descending branch of the thoracico-acromialis
artery. Its loiver border forms the anterior margin of the axilla, being at first
sei:)arated from the Latissimus dorsi by a considerable interval; but both muscles
gradually converge towards the outer part of this space.
Peculiarities. In well developed muscular subjects, the sternal origins of the two
Pectoral muscles ai'e separated only by a very narrow interval; but this interval
is enlarged in those cases where these muscles are ill developed. Very rarely, the
whole of the sternal portion is deficient. Occasionally, one or two additional
muscular slips arise from the aponeurosis of the Extei'nal oblique, and become
united to the lower margin of the Pectoralis major.
Dissection. The Pectoralis major should now be detached by dividing the muscle along
its attachment to the clavicle, and by making a vertical incision through its substance a
little external to its line of attachment to the sternum and costal cartilages. The muscle
should then be reflected outwards, and its tendon carefully examined.
The Pectoralis minor is now exposed, and immediately above it, in the interval
between its upper border and the clavicle, a strong fascia, the costo-coracoid
membrane. This fascia, which protects the axillary vessels and nerves, is very
thick and dense externally, where it is attached to the coracoid process, and is
continuous with the fascia of the arm; more internally, it is connected with the
lower border of the clavicle, as far as the inner extremity of the first rib: traced
downwards, it passes behind the Pectoralis minor, surrounding, in a more or less
complete sheath, the axillary vessels and nerves; and above, it sends a prolonga-
tion behind the Subclavius, which is attached to the lower border of the clavicle,
and so encloses this muscle in a kind of sheath. The costo-coracoid membrane is
pierced by the cephalic vein, the thoracico-acromialis artery and vein, superior
thoracic artery, and anterior thoracic nerve.
The Pectoralis Minor (fig. 153) is a thin, flat, triangular muscle, situated at
the upper part of the thorax, immediately beneath the Pectoralis major. It arises,
by three delicate tendinous digitations, from the upper margin and external sur-
face of the third, fourth, and fifth ribs, near their cartilages, and from the aponeu-
rosis covering the Intercostal muscles: the fieshy fibres succeeding to these unite,
and passing upwards and outwards, converge to form a flat tendon, which is in-
serted into the anterior and upper margin of the coracoid process of the scapula.
Relations. By its anterior surface, with the Pectoralis major, and the superior
thoracic vessels and nerves. By its posterior surface, with the ribs. Intercostal
muscles, Serratus magnus, the axillary space, and the axillary vessels and nerves.
Its superior border is separated from the clavicle by a triangular interval, broad
internally, narrow externally, bounded in front by the costo-coracoid membrane,
and internally by the ribs. In this space are seen the axillary vessels and nerves.
The costo-coracoid membrane should now be removed, when the Subclavius
muscle will be seen.
ANTERIOR THORACIC REGION.
245
The Subclaviiis is a long, thin, spindle-sliaped muscle, placed immediately
beneath the clavicle, in the interval between it and the first rib. It arises by a
short and thick tendon from the cartilage of the first rib, immediately in front of
the rhomboid ligament; the fleshy fibres proceed outwards to be inserted by short
tendinous fibres into a deep groove on the under surface of the middle third of the
clavicle.
Relations. By its upper surface, with the clavicle. By its under surface, it is
separated from the first rib by the axillary vessels and nerves. Its anterior
surface is separated from the Pectoralis major by a strong aponeurosis, which
with the clavicle, forms an osteo-fibrous sheath in which the muscle is enclosed.
153. — Muscles of the Chest and Front of the Arm, with the boundaries
of the Axilla.
If the costal attachment of the Pectoralis minor is divided across, and the muscle
reflected outwards, the axillary vessels and nerves are brought fully into view, and
should be examined.
Nerves. The Pectoral muscles are supplied by the anterior thoracic nerves; the
Subclavius, by a filament from the cord formed by the union of the fifth and sixth
cervical nerves.
Actions. If the arm has been raised by the Deltoid, the Pectoralis major will,
conjointly with the Latissimus dorsi and Teres major, depress it to the side of the
chest; and, if acting singly, it will draw the arm across the front of the chest.
The Pectoralis minor depresses the point of the shoulder, drawing the scapula
downwards and inwards to the thorax. The Subclavius depresses the shoulder,
246 MUSCLES AND FASCIiE.
drawing tlie clavicle dowriAvards and forwards. When the arms are fixed, all three
muscles act upon the ribs, drawing them upwards and expanding the chest, thus
becoming very important agents in forced inspiration. Asthmatic patients always
assume this attitude, fixing the shoulders, so that all these muscles may be brought
into action to assist in dilating the cavity of the chest.
Lateral Thoracic Region.
Serratus Magnus.
The Serratus Magnus is a broad, thin, and irregularly quadrilateral muscle,
situated at the upper part and side of the chest. It arises by eight fleshy digita-
tions from the external surface and upper borders of the eight upper ribs, and from
the aponeurosis covering the upper intercostal spaces, and is inserted into the whole
length of the inner margin of the posterior border of the scapula. This muscle
has been divided into three portions, a superior, middle, and inferior, on account
of the difference in the direction, and in the extent of attachment of each part.
The superior portion, separated from the rest by a cellular interval, is a narrow,
but thick fasciculus, consisting of the first digitation, which arises by a double
origin from the first and second ribs, and from the aponeurotic arch between them
(called by some authors, first and second serrations); its fibres proceed upwards,
outwards and backwards, to be inserted into the triangular smooth surface on the
inner side of the superior angle of the scapula. The middle portion of the muscle,
the broadest and thinnest of the three, consists of the second, third, and fourth
digitations, the fibres from which form a thin and broad muscular layer, which
proceeds horizontally backwards, to be inserted by short tendinous fibres into the
posterior border of the scapula, between the superior and inferior angles. The
largest portion of this division of the muscle is formed by the third digitation.
The inferior portion of the muscle consists of four digitations, in the intervals
between which are received corresponding processes of the External oblique; the
muscular fibres from these converging, pass upwards, outwards, and backwards, to
be inserted into the inner surface of the inferior angle of the scapula, by an attach-
ment partly muscular, partly tendinous.
Relations. This muscle is covered, in front, by the Pectoral muscles; behind,
by the Subscapularis; above, by the axillary vessels and nerves. Its deep surface
rests upon the ribs and intercostal spaces.
Nerves. The Serratus magnus is supplied by the posterior thoracic nerve.
Actions. The Serratus magnus is the most important external inspiratory
muscle. When the shoulders are fixed, it elevates the ribs, and so dilates the
cavity of the chest, assisting the Pectoral and Subclavius muscles. This muscle,
especially its middle and lower segments, draws the base and inferior angle
of the scapula forwards, and so raises the point of the shoulder by causing a rota-
tion of the bone on the side of the chest; assisting the Trapezius muscle in sup-
porting weights upon the shoulder, the thorax being at the same time fixed by
preventing the escape of the included air.
Dissection. After completing the dissection of the axilla, if the muscles of the back have
been dissected, the upper extremity should be separated from the trunk. Saw through
the clavicle at its centre, and then cut through the muscles which connect the scapula and
arm with the trunk, viz., the Pectoralis minor, in front, Serratus magnus, at the side, and
behind, the Levator anguli scapulse, the Rhomboids, Trapezius, and Latissimusdorsi. These
muscles should be cleaned and traced to their respective insertions. An incision should
then be made through the integument, commencing at the outer third of the clavicle, and
extending along the margin of this bone, the acromion process, and spine of the scapula ;
the integument should be dissected from above downwards and outwards, when the fascia
covering the Deltoid is exposed.
The Superficial Fascia of the upper extremity, is a thin cellulo-fibrous lamina,
containing between its layers the superficial veins and lymphatics, and the cuta-
neous nerves. It is most distinct in front of the elbow, and contains between
its laminae in this situation the large superficial cutaneous veins and nerves; in
LATERAL THORACIC AND ACROMIAL REGIONS. 247
the hand it is hardly demonstrable, the integument being closely adherent to the
deep fascia by dense fibrous bands. Small subcutaneous bursas are found in this
fascia, over the acromion, the olecranon, and the knuckles. The deep fascia of
the upper extremity comprises the aponeurosis of the shoulder, arm, and fore-arm,
the anterior and posterior annular ligaments of the carpus, .and the palmar fascia.
These will be considered in the description of the muscles of these several regions.
AcROBiiAL Region.
Deltoid.
The Deep Fascia covering the Deltoid (deltoid aponeurosis) is a thick and
strong fibrous layer, which covers the outer surface of the muscle, and sends down
numerous prolongations between its fasciculi; it is continuous internally with that
covering the great Pectoral muscle; behind, with the aponeurosis covering the
Infra-spinatus and back of the arm; above, it is attached to the clavicle, the acro-
mion, and spine of the scapula.
The Deltoid is a large thick triangular muscle, which forms the convexity
of the shoulder, and has received its name from its resemblance to the Grreek
letter A reversed. It surrounds the shoulder -joint in the greater part of its
extent, covering it on its outer side, and in front and behind. It arises, by tendi-
nous fibres, from the outer third of the anterior border and upper surface of the
clavicle; from the external margin and upper surface of the acromion process;
and from the whole length of the inferior border of the spine of the scapula, as far
back as the triangular surface which terminates it. From this extensive origin,
the muscular fibres proceed downwards, and converge towards their insertion, the
middle passing vertically, the anterior obliquely backwards, the posterior obliquely
forwards; they unite to form a thick tendon, which is inserted into a rough pro-
minence on the middle of the outer side of the shaft of the humerus. This muscle
is remarkably coarse in its texture, and intersected by three or four tendinous
laminge, attached at intervals to the clavicle and acromion; these extend into the
substance of the muscle, and give origin to a number of fleshy fibres. The largest
of these laminae extends from the summit of the acromion.
Relations. By its superficial surface, with the Platysma, supra- acromial nerves,
the superficial fascia, and integument. By its deep surface, it is separated from
the Scapular muscles covering the head of the humerus by a large sacculated
synovial bursa, and covers the coracoid process, coraco-acromial ligament, Pecto-
ralis minor, Coraco-brachialis, both heads of the Biceps, tendon of the Pectoralis
lajor, Teres major. Scapular, and external headsof the Triceps, the circumfiex vessels
md nerve, and the humerus. Its anterior border is separated from the Pectoralis
lajor by a cellular interspace, which lodges the cephalic vein and descending
branch of the thoracico-acromialis artery. Its posterior border is thin above,
Tthicker below, and bound down by the aponeurotic covering of the Infra-spinatus.
Nerves. The Deltoid is supplied by the circumflex nerve.
Actions. The Deltoid serves to raise the arm directly from the side, and to
[bring it at right angles with the trunk. Its anterior fibres, assisted by the Pecto-
Iralis major, draw the arm forwards; and its posterior fibres, aided by the Teres
[major and Latissimus dor si, will draw it backwards.
Dissection. Divide the Deltoid across, near its upper part, by an incision carried along
the margin of the clavicle, the acromion process, and spine of the scapula, and reflect it
downwards ; the bursa will be seen on its under surface, as well as the circumflex vessels
and nerves, and External rotator muscle. The insertion of the muscle should be care-
!_ fully - examined.
Anterior Scapular Region,
Subscapularis.
The Subscapular Aponeurosis is a thin membrane, attached to the entire cir-
cumference of the subscapular fossa, and afibrding attachment by its inner surface
248 MUSCLES AND FASCIA.
to some of the fibres of the Subscapularis muscle: when this is removed the Sub-
scapularis muscle is exposed.
The Subscapularis is a large triangular muscle, which fills up the whole of the
subscapular fossa, arising from its internal two-thirds, with the exception of a
narrow margin along the posterior border, and the small triangular portions of
bone on the inner side of the superior and inferior angles, which afford attach-
ment to the Serratus magnus. Some of the fibres arise from tendinous lamina3,
which intersect the muscle, and are attached to ridges on the bone; and others
from an aponeurosis attached to the anterior margin of the axillary border of the
scapula, which separates this muscle from the Teres major and the long head of
the Triceps. From this origin, the fibres pass outwards, and gradually converging,
the muscle becomes narrow and thick, and terminates in a tendon, which is inserted
into the lesser tuberosity of the humerus. Some of the muscular fibres which arise
from the axillary border of the scapula are inserted into the neck of the bone to
the extent of an inch below the tuberosity. The tendon of this muscle is in close
contact with the capsular ligament of the shoulder-joint, and glides over a large
bursa, which separates it from the base of the coracoid process. This bursa com-
municates with the cavity of the joint by an aperture in the capsular ligament.
Relations. By its anterior surface, with the Serratus magnus, some loose areolar
tissue being interposed, the Coraco-brachialis, and Biceps, and the axillary vessels
and nerves. By its posterior surface, with the scapula, the subscapular vessels
and nerves, and the capsular ligament of the shoulder -joint.
Nerves. It is supplied by the subscapular nerves.
Actions. The Subscapularis rotates the head of the humerus inwards; when the
arm is raised it draws the humerus downwards. It is a powerful defence to the
front of the shoulder-joint, preventing displacement of the head of the bone for-
wards.
Posterior Scapular Region.
Supra-spinatus. Teres Minor.
Infra-spinatus. Teres Major.
Dissection. To expose these muscles, and to examine their mode of insertion into the
humerus, detach the Deltoid and Trapezius from their attachment to the spine of the
scapula and acromion process. Eemove the clavicle by dividing the ligaments connecting
it with the coracoid process, and separate it at its articulation with the scapula : divide
the acromion process near its root with a saw, and the fragment being removed, the ten-
dons of the posterior Scapular muscles will be fully exposed, and can be examined. A
block should be placed beneath the shoulder-joint, so as to make the muscles tense.
The Supraspinous Aponeurosis is a thick and dense membranous layer, attached
to the entire circumference of the supra-spinous fossa, and completing the osteo-
fibrous case in which the Supra-spinatus muscle is contained: by its inner surface
it affords attachment to some of the fibres of this muscle. It is very thick inter-
nally, but thinner externally under the cor aco- acromion ligament. When this
fascia is removed, the Supra-spinatus muscle is exposed.
The Supra-spinatus is a thick triangular muscle, which occupies the whole of
the supra-spinous fossa, arising from its internal two-thirds, and from a strong
fascia which covers the muscle and completes the osteo-fibrous sheath in which
it is enclosed. From these points, the muscular fibres converge to a tendon, which
passes across the capsular ligament of the shoulder-joint, to which it is intimately
adherent, and is inserted into the highest of the three facets on the great tuberosity
of the humerus.
Relations. By its upper surface, with the Trapezius, the clavicle, the acromion,
the coraco-acromion ligament, and the Deltoid. By its under surface, with the
scapula, the supra-scapular vessels and nerve, and upper part of the shoulder-
joint.
The Infra-spinous Aponeurosis is a dense fibrous membrane, covering in the
Infra-spinatus muscle, and attached to the entire circumference of the infra-spinous
SCAPULAR REGIONS.
249
fossa; it affords attachment by its inner surface to some fibres of this muscle, is
continuous externally with the fascia of the arm, and gives off from its under
surface intermuscular septa, which separate it from the Teres minor, and the latter
from the Teres major.
The Infra-spinatus is a thick triangular muscle, which occupies the chief part
of the infra-spinous fossa, arising by fleshy fibres, from its internal two-thirds; and
by tendinous fibres, from the ridges on its surface: it also arises from a strong
fascia which covers it externally, and separates it from the Teres major and
minor. The fibres converge to a tendon, which glides over the concave border of
the spine of the scapula, and passing across the capsular ligament of the shoulder-
154. — Muscles on the Dorsum of the Scapula and the Triceps.
\
joint, is inserted into the middle facet on the great tuberosity of the humerus.
The tendon of this muscle is occasionally separated from the spine of the scapula
by a synovial bursa, which communicates with the synovial membrane of the
shoulder-joint.
Relations. By its posterior surface, with the Deltoid, the Trapezius, Latissimus
dorsi, and the integument. By its anterior surface, with the scapula, from which
it is separated by the superior and dorsalis scapulte vessels, and with the capsular
ligatnent of the shoulder-joint. Its lower border is in contact with the Teres
minor, and occasionally united with it, and with the Teres major.
The Teres 3finor is a narrow elongated muscle, which lies along the inferior
border of the scapula. It arises from the dorsal surface of the axillary border of
the scapula for the upper two-thirds of its extent, and from two aponeurotic
laminae, which separate this muscle, one from the Infra-spinatus, the other from
250 MUSCLES AND FASCIiE.
the Teres major; its fibres pass obliquely upwards and outwards, and terminate in
a thick tendon, which is inserted below the Infra- spinatus into the lowest of the
three facets on the great tuberosity of the humerus, and, by fleshy fibres, into
the humerus immediately below it. The tendon of this muscle, passes across
the capsular ligament of the shoulder-joint.
Relations. By its posterior surface, with the Deltoid, Latissimus dorsi, and
integument. By its anterior surface, with the scapula, the dorsal branch of the
subscapular artery, the long head of the Triceps, and the shoulder -joint. By its
upper border, with the Infra-spinatus. By its lower border, with the Teres
major, from which it separated anteriorly by the long head of the Triceps.
The Teres Major is a broad and somewhat flattened muscle, which arises from
the triangular surface on the dorsal aspect of the inferior angle of the scapula,
and from the fibrous septa interposed between it and the Teres minor and Infra-
spinatus; the fibres are directed upwards and outwards, and terminate in a flat
tendon, about two inches in length, which is inserted into the posterior border of
the bicipital groove of the humerus. The tendon of this muscle lies immediately
behind that of the Latissimus dorsi, from which it is separated by a synovial
bursa; it is also placed a little below that muscle at its insertion into the humerus.
Relations. By its posterior surface, with the integument, from which it is sepa-
rated internally by the Latissimus dorsi, and externally by the long head of the
Triceps. By its anterior surface, with the Subscapularis, Latissimus dorsi,
Coraco-brachialis, short head of the Biceps, the axillary vessels, and brachial plexus
of nerves. Its upper border, is at first in relation with the Teres minor, from
which it is afterwards sejaarated by the long head of the Triceps. Its loioer
border forms, in conjunction with the Latissimus dorsi, part of the posterior boun-
dary of the axilla.
Nerves. The Supra and Infra-spinati muscles are supplied by the supra-
scapular nerve; the Teres minor, by the circumflex; and the Teres major by the
subscapular.
Actions. The Supra- spinatus assists the Deltoid in raising the arm from the side;
its action must, however, be very feeble, from the very disadvantageous manner in
which the force is applied. The Infra-spinatus and Teres minor rotate the head
of the humerus outwards; when the arm is raised, they assist in retaining it in
that position, and carrying it backwards. One of the most important uses of
these three muscles, is the great protection they afford to the shoulder joint, the
Supra-spinatus supporting it above, and preventing displacement of the head of
the humerus upwards, whilst the Infra-spinatus and Teres minor protect it behind,
and prevent dislocation backwards. The Teres major assists the Latissimus dorsi
in drawing the humerus downwards and backwards when previously raised, and
rotating it inwards; when the arm is fixed, it may assist the Pectoral and Latis-
simus dorsi muscles in drawing the trunk forwards.
Anterior Humeral Region.
Coraco-Brachialis. Biceps. Brachialis Anticus.
Dissection. The arm being placed on the table, with the front surface uppermost, make
a vertical incision through the integument along the middle line, from the middle of the
interval between the folds of the axilla, to about two inches below the elbow joint, where
it should be joined by a transverse incision, extending from the inner to the outer side of
the fore-arm ; the two flaps being reflected on either side, the fascia should be examined.
The Deep Fascia of the arm, continuous with that covering the shoulder and
front of the great Pectoral muscle, is attached, above, to the clavicle, acromion,
and spine of the scapula; it forms a thin, loose, membranous sheath investing the
muscles of this region, sending down septa between them, and composed of fibres
disposed in a circular or spiral direction, and these being connected together by
vertical fibres. It differs in thickness at different parts, being thin over the Biceps,
but thicker where it covers the Triceps and over the condyles of the humerus, and is
strengthened by fibrous aponeuroses, which it derives from the Pectoralis major
ANTERIOR HUMERAL REGION.
251
and Latissiraus dorsi, on the inner side, and from the Deltoid, externally. On
either side it gives off a strong intermuscular septum, which is attached to the
condyloid ridge and condyles on either side of the humerus. These septa serve
to separate the muscles of the anterior, from those of the posterior brachial region.
The external intermuscular septum extends from the lower part of the anterior
bicipital ridge, along the external condyloid ridge, to the outer condyle; it is
blended with the tendon of the Deltoid; gives attachment to the Triceps behind,
to the Brachialis anticus. Supinator longus, and Extensor carpus radialis longior,
in front; and is perforated by the musculo-spiral nerve, and superior profunda
artery. The internal intermuscular septum, thicker than the preceding, extends
from the lower part of the posterior bicipital groove below the Teres major, along
the internal condyloid ridge to the inner condyle; it is blended with the tendon of
the Coraco-brachialis, and affords attachment to the Triceps, behind, and the
Brachialis anticus, in front. It is perforated by the ulnar nerve, and the inferior
profunda and anastomotic arteries. At the elbow the deep fascia takes attachment
to all the prominent points around this joint, and is continuous with the fascia of
the fore-arm. On the removal of this fascia the muscles of the anterior humeral
region are exposed.
The Cor aco- Brachialis, the smallest of the three muscles in this region, is
situated at the upper and inner part of the arm. It arises from the apex of the
coracoid process of the scapula, in common with the short head of the biceps, and
from the inter-muscular septum between these two muscles; the fibres pass down-
wards, backwards, and a little outwards, to be inserted by means of a flat tendon
into a rough line at the middle of the inner side of the shaft of the humerus. It
is perforated by the musculo-cutaneous nerve. The inner border of this muscle
forms a guide to the performance of the operation of tying the brachial artery in
the upper part of its course.
Relations. By its anterior surface, with the Deltoid and Pectoralis major above,
at its insertion it is crossed by the brachial artery. By its posterior surface, with
the tendons of the Subscapularis, Latissimus dorsi, and Teres major, the short head
of the Triceps, the humerus, and the anterior circumflex vessels. By its inner
border, with the brachial artery, and the median and musculo-cutaneous nerves.
By its outer border, with the short head of the Biceps and Brachialis anticus.
The Biceps is a long fusiform muscle, situated along the anterior aspect of the
arm its entire length, and divided above into two portions or heads, from which
circumstance it has received its name. Its internal or short head arises by a thick
flattened tendon from the apex of the coracoid process of the scapula, in common
with the Coraco-brachialis. The external or long head, arises from the upper
margin of the glenoid cavity of the scapula, by a long rounded tendon, which is
continuous with the glenoid ligament. This tendon passes across the head of the
humerus, being enclosed in a special sheath of the synovial membrane of the
shoulder joint; it then pierces the capsular ligament at its attachment to the
humerus, and descends in the bicipital groove which separates the two tuberosities
in which it is retained by a sort of fibrous bridge. The fibres from this tendon
form a rounded belly, which about the middle of the arm joins with the short
portion of the muscle. The belly of the muscle, narrow and somewhat flattened,
terminates above the elbow in a flattened tendon, which is inserted into the
posterior part of the tuberosity of the radius, a synovial bursa being interposed
between the tendon and the anterior part of the tuberosity. The tendon of this
muscle is thin and broad; as it approaches the radius it becomes narrowed and
twisted upon itself, being applied by a flat surface to the posterior part of the
tuberosity, and opposite the bend of the elbow gives off, from its inner side, a
broad aponeurosis, which passes obliquely downwards and inwards across the
brachial artery, and is continuous with the fascia of the fore-arm. The inner
border of this muscle forms a guide to the performance of the operation of tying
the brachial artery in the middle of the arm.
Relations. Its anterior surface is overlapped above by the Pectoralis major and
252 MUSCLES AND FASCI-^.
Deltoid; in the rest of its extent it is covered by the superficial and deep fascife
and the integument. Its posterior surface rests on the shoulder-joint and humerus,
from which it is separated by the Subscapularis, Teres major, Latissimus dorsi,
Brachialis anticus, and the musculo-cutaneous nerve. Its inner border is in rela-
tion with the Coraco-brachialis, the brachial vessels, and median nerve. By its
outer border, with the Deltoid and Supinator longus.
The Brachialis Anticus is a broad muscle, which covers the whole of the ante-
rior svirface of the lower part of the humerus. It is somewhat compressed from
before backwards, and is broader in the middle than at either extremity. It arises
from the lower half of the external and internal surfaces of the shaft of the
humerus, commencing above at the insertion of the Deltoid, which it embraces by
two well marked angular processes, and extending, below, to within an inch of the
margin of the articular surface, and being limited on each side by the external
and internal borders. It also arises from the inter-muscular septa on each side,
but more extensively from the inner than the outer. Passing down in front of
the elbow joint, its fibres converge to a thick tendinous fasciculus, which is inserted
into a rough depression on the lower part of the coronoid process of the ulna, being
received into a notch at the upper part of the Flexor digitorum profundus.
Relations. By its anterior surface, with the Biceps, musculo-cutaneous nerve,
the brachial vessels, and median nerve. By its posterior surface, with the humerus
and anterior ligament of the elbow joint. By its inner border, with the Triceps,
ulnar nerve, and Pronator radii teres, from which it is separated by the inter-
muscular septa. By its outer border, with the musculo-spiral nerve, radial recur-
rent artery, the Supinator longus, and Extensor carpi radialis longior.
Nerves. The muscles of this group are supplied by the musculo-cutaneous nerve.
The Brachialis anticus receives an additional filament from the musculo-spiral.
Actions. The Coraco-brachialis draws the humerus forwards and inwards, and
at the same time assists in elevating it towards the scapula. The Biceps and
Brachialis anticus are flexors of the fore-arm; the former muscle is also a supina-
tor, and serves to render tense the fascia of the fore-arm by means of the broad
aponeurosis given off from its tendon. When the fore-arm is fixed, the Biceps
and Brachialis anticus flex the arm upon the fore-arm, as is seen in the efforts of
climbing. The Brachialis anticus forms an important defence to the elbow joint.
Posterior Humeral Region.
Triceps. Subanconeiis.
The Triceps is the only muscle situated on the back of the arm, extending
the entire length of the posterior surface of the humerus. It is of large size, and
divided above into three portions or heads; hence the name of the muscle. These
three portions have been named, the middle or long head, the external, and the
internal or short head.
The middle or long head arises, by a flattened tendon, from a rough triangular
depression, immediately below the glenoid cavity of the scapula, being blended at
its upper part with the glenoid ligament; the muscular fibres pass downwards
between the two other portions of the muscle, and join with them in the common
tendon of insertion.
The external head arises from the posterior surface of the shaft of the humerus,
between the insertion of the Teres minor and the upper part of the musculo-spiral
groove, from the external border of the humerus and external intermuscular
septum: the fibres from this origin converge towards the common tendon of
insertion.
The internal or short head arises from the whole of the posterior surface of the
shaft of the humerus, below the groove for the musculo-spiral nerve, commencing
above, narrow and pointed, immediately below the insertion of the Teres major,
and extending, below, to Avithin an inch of the trochlear surface; it also arises
from the internal border and internal intermuscular septum. The fibres of this
POSTERIOR HUMERAL REGION. 253
portion of the muscle are directed, some downwards to the olecranon, whilst others
converge to the common tendon of insertion.
The common tendon of the Triceps commences about the middle of the back
part of the muscle: it consists of two aponeurotic laminae, one of which is sub-
cutaneous, and covers the posterior surface of the muscle for the lower half of its
extent; the other layer is more deeply seated in the substance of the muscle: after
receiving the attachment of the muscular fibres, they join together immediately
above the elbow, and are inserted into the posterior part of the upper surface of
the olecranon process, a small bursa, occasionally multilocular, being interposed
between the tendon and the front of this surface.
The long head of the Triceps passes between the Teres minor and Teres major,
dividing the triangular space between these two muscles and the humerus into two
smaller spaces, one triangular, the other quadrangular (fig. 154). The triangular
space transmits the dorsalis scapulas artery and veins, being bounded by the Teres
minor above, the Teres major below, and the scapular head of the Triceps ex-
ternally: the qviadrangular space transmits the posterior circumflex vessels and
nerve; it is bounded by the Teres minor above, the Teres major below, the sca-
pular head of the Triceps internally, and the humerus externally.
Relations. By its posterior surface, with the integument, superficial and deep
fascia, and integument. By its anterior surface, with the humerus, musculo-
spiral nerve, sujDerior profunda artery, and back part of the elbow-joint. Its
middle or long head is in relation, behind, with the Deltoid and Teres minor; in
front, with the Subscapularis, Latissimus dorsi, and Teres major.
Subanconeus. This is a small muscle, distinct from the Triceps, and analogous
to the Subcrureus in the lower limb. It may be exposed by removing the Triceps
from the lower part of the humerus. It consists of one or two slender fasciculi,
which arise from the humerus, immediately above the olecranon fossa, and are
inserted into the posterior ligament of the elbow-joint.
Nerves. The Triceps and Subanconeus are supplied by the musculo-spii-al
nerve.
Actions. The Triceps is the great Extensor muscle of the fore-arm; when the
fore-arm is flexed, serving to draw it into a right line with the arm. It is the
direct antagonist of the Biceps and Brachialis anticus. When the arm is extended,
the long head of this muscle may assist the Teres major and Latissimus dorsi in
drawing the humerus backwards. The long head of the Tricejis protects the
under part of the shoulder-joint, and prevents displacement of the head of the
humerus downwards and backwards.
Muscles of the Fore-arm.
Dissection. To dissect the fore-arm, place the limb in the position indicated in fig. 151;
make a vertical incision along the middle line from the elbow to the wrist, and connect
each extremity with a transverse incision ; the flaps of integument being removed, the
fascia of the fore-arm is exposed.
The Deep Fascia of the fore-arm, continuous above with that enclosing the arm,
is a dense highly glistening aponeurotic investment, which forms a general sheath
enclosing all the muscles in this region; it is attached behind to the olecranon and
posterior border of the ulna, and gives ofi* from its inner surface numerous inter-
muscular septa, which enclose each muscle separately. It consists of circular and
oblique fibres, connected together at right angles by numerous vertical fibres. It
is much thicker on the dorsal than on the palmar surface, and at the lower than
at the upper part of the fore-arm, and is strengthened by tendinous fibres, derived
from the Brachialis anticus and Biceps in front, and from the Triceps behind.
Its inner surface affords extensive origin for muscular fibres, especially at the
upper part of the inner and outer sides of the fore-arm, and forms the boundaries
of a series of conical- shaped fibrous cavities, in which the muscles in this region
are contained. Besides the vertical septa separating , each muscle, transverse
septa are given oiF both on the anterior and posterior surfaces of the fore-arm.
254
MUSCLES AND FASCIA.
separating the deep from the superficial layer of muscles. Numerous apertures
exist in the fascia for the passage of vessels and nerves; one of these, of large
size, situated at the front of the bend of the elbow, serves for the passage of a
communicating branch between the superficial and deep veins.
The muscles of the fore-arm may be subdivided into groups corresponding to
the region they occupy. The first group occupies the inner and anterior aspect of
the fore-arm, and comprises the Flexor and Pronator muscles. The second group
occupies the outer side of the fore-arm; and the third, its posterior aspect. The
two latter groups include all the Extensor and Supinator muscles.
Anterior Brachial Region.
155.
-Front of the Left Fore-arm.
Superficial Muscles.
Superficial Layer.
Pronator radii teres.
Flexor carpi radialis.
Palmaris longus.
Flexor carpi ulnaris.
Flexor sublimis digitorum.
All these muscles take origin from
the internal condyle by a common
tendon.
The Pronator Radii Teres arises
by two heads. One, the largest and
most, superficial, from the humerus,
immediately above the internal condyle,
and from the tendon common to the
origin of the other muscles; also from
the fascia of the fore-arm, and inter-
muscular septum between it and the
Flexor carpi radialis. The other head
is a thin fasciculus, which arises from
the inner side of the coronoid process
of the ulna, joining the other at an
acute angle. Between the two heads
passes the median nerve. The muscle
passes obliquely across the fore-arm
from the inner to the outer side, and
terminates in a flat tendon, which
turns over the outer margin of the
radius, and is inserted into a rough
ridge at the middle of the outer sur-
face of the shaft of that bone.
Relations. By its anterior surface,
with the fascia of the fore-arm, the Su-
pinator longus, and the radial vessels
and nerve. By its posterior surface,
with the Brachialis anticus. Flexor
sublimis digitorum, the median nerve,
and ulnar artery. Its upper border
forms the inner boundary of a trian-
gular space, in which is placed the
brachial artery, median nerve, and
tendon of the Biceps muscle. Its
lower border is in contact with the
Flexor carpi radialis. ^""~~^^-
ANTERIOR BRACHIAL REGION.
255
The Flexor Carpi Radialis lies on the inner side of the preceding muscle.
It arises from the internal condyle by the common tendon, from the fascia of the
fore-arm, and from the inter-muscular septa between it and the Pronator teres, on
the inside; the Palmaris longus, externally; and the Flexor sublimis digitorum,
Ijeneath. Slender and aponeurotic in structure at its commencement, it increases
in size, and terminates in a tendon which forms the lower two-thirds of its struc-
ture. This tendon passes through a separate opening on the outer side of the
annular ligament, runs through a groove in the os trapezium, converted into a
canal by a thin fibrous sheath, lined by a synovial membrane, and is inserted into
the base of the metacarpal bone of the index finger. The radial artery lies
between the tendon of this muscle and the Supinator longus, and may easily be
secured in this situation.
Relations. By its superficial surface, with the fascia of the fore-arm and the
integument. By its deep surface, with the Flexor sublimis digitorum. Flexor
longus pollicis, and wrist joint. By its outer border, with the Pronator radii teres,
and the radial vessels. By its inner border, with the Palmaris longus.
The Palmaris Longus is a slender fusiform muscle, lying on the inner side of
the preceding. It arises from the inner condyle of the humerus by the common
tendon, from the fascia of the fore-arm, and inter-muscular septa, between it and
the adjacent muscles. It terminates in a slender flattened tendon, which forms
the lower two-thirds of its structure, being inserted into the annular ligament, and
expanding to be continuous Avith the palmar fascia.
Variations. This muscle is often found wanting; when it exists, it presents
many varieties. Its fleshy belly is sometimes very long, or it may occupy the
middle of the muscle, which is tendinous at either extremity; or it may be mus-
cular at its lower extremity, its upper part being tendinous. Occasionally there
is a second Palmaris longus placed on the inner side of the preceding, terminating,
below, partly in the annular ligament or fascia, and partly in the small muscles of
the little finger.
Relations. By its anterior surface, with the fascia of the fore-arm. By its
posterior surface, with the Flexor digitorum sublimis. Internally, with the
Flexor carpi ulnaris. Externally, with the Flexor carpi radialis.
The Flexor carpi ulnaris lies along the ulnar side of the fore-arm. It arises
by two heads, separated by a tendinous arch, beneath which passes the ulnar nerve,
and posterior ulnar recurrent artery. One head arises from the inner condyle of
the humerus, by the common tendon; the other, from the inner margin of the
olecranon, and by an aponeurosis from the upper two-thirds of the posterior border
of the ulna. It also arises from the inter-muscular septum between it and the
Flexor sublimis digitorum. The muscular fibres terminate in a tendon, which is
inserted on the anterior surface of the pisiform bone, the tendon being pro-
longed to the annular ligament and base of the metacarpal bone of the little finger.
The ulnar artery lies on the outer side of the tendon of this muscle, in the lower
two-thirds of the fore-arm; the tendon forming a guide to the operation of in-
cluding this vessel in a ligature in this situation.
Relations. By its anterior surface, with the fascia of the fore-arm, with which
it is intimately connected for a considerable extent. By its posterior surface, with
the Flexor sublimis, the Flexor profundus, the Pronator quadratus, and the ulnar
Ivessels and nerve. By its outer or radial border, with the Palmaris longus, above;
ibelow, with the ulnar vessels and nerve.
The Flexor Digitorum Sublimis is placed beneath the preceding muscles; these
therefore require to be removed before its entire extent of attachment is brought
into view. It is the largest of the muscles of the superficial layer, and arises by
tthree distinct heads. One from the internal condyle of the humerus by the com-
Imon tendon, from the internal lateral ligament of the elbow joint, and from the
I inter-muscular septum common to it and the preceding muscles. The second head
[^arises from the coronoid process of the ulna, above' the ulnar origin of the Pro-
lator radii teres. The third head arises by tendinous fibres from the oblique line
256 MUSCLES AND FASCIiE.
of the radius, extending from the tubercle above, to the insertion of the Pronator
radii teres below. The muscular fibres pass vertically downwards, forming a
broad and thick muscle, which divides into four tendons about the middle of the
fore-arm; as these tendons pass beneath the annular ligament into the palm of the
hand, they are arranged in pairs, the anterior pair corresponding to the middle and
ring fingers; the posterior pair to the index and little fingers. The tendons
diverge from one another as they pass onwards, and are finally inserted into the
lateral margins of the second phalanges, about their centre. Opposite the base of
the first phalanges, each tendon divides, so as to leave a fissured interval, between
which passes one of the tendons of the Flexor profundus, and they both enter an
osso-aponeurotic canal, formed by a strong fibrous band which arches across them,
and is attached on each side to the mai'gins of the phalanges. The two portions
into which the tendon of the Flexor sublimis divides, so as to admit of the passage
of the deep flexor, expand somewhat, and form a grooved channel into which the
accompanying deep flexor tendon is received; the two divisions then unite, and
finally subdivide a second time to be inserted into the fore part and sides of the
second phalanges. The tendons whilst contained in the fibro-osseous canals are
connected to the phalanges by slender tendinous filaments, called vincula acces-
soria tendinum. A synovial sheath invests the tendons as they pass beneath the
annular ligament; a similar membrane surrounds each tendon as it passes along
the phalanges.
Relations. In the fore-arm. By its anterior surface, with the deep fascia and
all the preceding superficial muscles. By its posterior surface, with the Flexor
profundus digitorum, Flexor longus pollicis, the ulnar vessels and nerves, and the
median nerve. In the hand, its tendons are in relation, in front, with the palmar
fascia, superficial palmar arch, and the branches of the median nerve. Behind,
with the tendons of the deep Flexor and the Lumbricales.
Anterior Brachial Region.
Deep Layer.
Flexor Profundus Digitorum. Flexor Longus Pollicis.
Pronator Quadratus.
Dissection. Divide each of the superficial muscles at its centre, and turn either end aside,
the deep layer of muscles, together with the median nerve and ulnar artery, will then be
exposed.
The Flexor Profundtis Digitorum {perforans) is situated on the ulnar side of
the fore-arm, immediately beneath the superficial Flexors. It arises from the upper
two-thirds of the anterior and internal surfaces of the shaft of the ulna, embracing
above, the insertion of the Brachialis anticus, and extending, below, to within a
short distance of the Pronator quadratus. It also arises from a depression on the
inner side of the coronoid process, by an aponeurosis from the upper two-thirds of
the posterior border of the ulna, and from the ulnar half of the interosseous mem-
brane. The fibres from these origins pass downwards, forming a fleshy belly of
considerable size, which divides into four unequal portions, each of which termi-
nates in a tendon which passes beneath the annular ligament beneath the tendons of
the Flexor sublimis. Opposite the first phalanges, the tendons pass between the
two slips of the tendons of the Flexor sublimis, and are finally inserted into the
bases of the last phalanges. The tendon of the index finger is distinct; the rest
are connected together by cellular tissue and tendinous slips, as far as the palm of
the hand.
Four small muscles, the Lumbricales, are connected with the tendons of the
Flexor profundus in the palm. They will be described with the muscles in that
region.
Relations. By its anterior surface, in the fore-arm, with the Flexor sublimis
digitorum, the Flexor carpi ulnaris, the ulnar vessels and nerve, and the median
nerve; and in the hand, with the tendons of the superficial Flexor. By its
ANTERIOR BRACHIAL RECIION.
257
posterior surface, in the fore-
arm, with the ulna, the inter-
osseous ligament, the Pronator
quadratus; and in the hand,
with the Interossei, Adductor
pollicis, and deep palmar arch.
By its ulnar border, with the
Flexor carpi ulnaris. By its
radial border, with the Flexor
longus pollicis, the anterior
interosseous artery and nerve
being interposed.
The Flexor Longus Polli-
cis is situated on the radial
side of the fore-arm, lying on
the same plane as the prece-
ding. It arises from the up-
per two-thirds of the grooved
anterior surface of the shaft
of the radius; commencing,
above, immediately below the
tuberosity and oblique line,
and extending, below, to with-
in a short distance of the
Pronator quadratus. It also
arises from the adjacent part
of the interosseous membrane,
and occasionally by a fleshy
slip from the inner side of the
base of the coronoid process.
The fibres pass downwards
and terminate in a flattened
tendon, which passes beneath
the annular ligament, is then
lodged in the inter- space be-
tween the two heads of the
Flexor brevis pollicis, and
entering a tendino-osseous ca-
nal, similar to those for the
other flexor tendons, is in-
serted into the base of the
last phalanx of the thumb.
Relations. By its anterior
surface, with the Flexor sub-
limis digitorum. Flexor carpi
radialis. Supinator longus, and
radial vessels. By its poste-
rior surface, with the radius,
interosseous membrane, and
Pronator quadratus. By its
ulnar border, with the Flexor
profundus digitorum, from
which it is separated by the
anterior interosseous artery
and nerve.
The Pronator Quadratus
is a small muscle, quadrilateral
156. — Front of the Left Fore-arm. Deep Muscles.
258 „ MUSCLES AND FASCIA..
in form, extending transversely across the radius and ulna, immediately above
their carpal extremities. It arises from the oblique line on the lower fourth of
the anterior surface of the shaft of the ulna, and the surface of bone immediately
below it; from the internal border of the ulna; and from a strong aponeurosis
which covers the inner third of the muscle. The fibres pass horizontally out-
wards, to be inserted into the lower fourth of the anterior surface and external
border of the shaft of the radius.
Relations. By its anterior surface, with the Flexor profundus digitorvim, the
Flexor longus poUicis, Flexor carpi radialis, and the radial and ulnar vessels, and
ulnar nerve. By its posterior surface, with the radius, ulna, and interosseous
membrane.
Nerves. All the muscles of the superficial layer are supplied by the median
nerve, excepting the Flexor carpi ulnaris, whicli, is supplied by the ulnar. Of
the deep layer, the Flexor profundus digitorum is supplied conjointly by the
ulnar and anterior interosseus nerves, the Flexor longus pollicis and Pronator
quadratus by the anterior interosseous nerve.
Actions. These muscles act upon the fore-arm, the wrist, and hand. Those
acting on the fore-amn, are the Pronator radii teres and Pronator quadratus, which
rotate the radius upon the ulna, rendering the hand prone; when pronation has
been fully effected, the Pronator radii teres assists the other muscles in flexing
the fore-arm. The flexors of the wrist are the Flexor carpi ulnaris and radialis;
and the flexors of the phalanges are the Flexor sublimis and Profundus digitorum;
the former flexing the second phalanges, and the latter the last. The Flexor longus
pollicis flexes the last phalanx of the thumb. The three latter muscles, after flexing
the phalanges by continuing their action, act upon the wrist, assisting the ordinary
flexors of this joint; and all assist in flexing the fore-arm upon the arm. The
Palmaris longus is a tensor of the palmar fascia; when this action has been fully
effected, it flexes the hand upon the fore-arm.
Radial Region.
Supinator Longus. Extensor Carpi Radialis Longior.
Extensor Carpi Radialis Brevior.
Dissection. Divide the integument in the same manner as in the dissection of the ante-
rior brachial region ; and after having examined the cutaneous vessels and nerves and deep
fascia, they should be removed, when the muscles of this region will be exposed. The
removal of the fascia will be considerably facilitated by detaching it from below upwards.
Great care should be taken to avoid cutting across the tendons of the muscles of the
thumb.
The Supinator Longus is the most superficial muscle on the radial side of
the fore-ai*m, fleshy for the upper two-thirds of its extent, tendinous below. It
arises from the upper two-thirds of the external condyloid ridge of the humerus,
and from the external intermuscular septum being limited above by the musculo-
spiral groove. The fibres descend on the anterior and outer side of the fore-arm,
and terminate in a flat tendon, which is inserted into the base of the styloid pro-
cess of the radius.
Relations. By its superficial surface, with the integument and fascia for the
greater part of its extent; near its insertion it is crossed by the Extensor ossis
metacarpi pollicis and the Extensor primi internodii pollicis. By its deep surface,
with the humerus, the Extensor carpi radialis longior and brevior, the insertion of
the Pronator radii teres, and the Supinator brevis. By its imier border, above the
elbow with the Brachialis anticus, the musculo-splral nerve, and radial recurrent
artery; and in the fore-arm, with the radial vessels and nerve.
The Extensor Carpi Radialis Longior is placed partly beneath the preceding
muscle. It arises from the lower third of the external condyloid ridge of the,
humerus, immediately below the Supinator longus, and from the external inter-
muscular septum. The fibres pass downwards, and terminate at the upper third
of the fore-arm in a flat tendon, which runs along the outer border of the radius.
RADIAL REGION.
259
157. — Posterior Surface of Forearn. Superficial Muscles.
beneath the extensor tendons
of the thumb; it then passes
through a groove common to
it and the Extensor carpi
radialis brevior, immediately
behind the styloid process;
and is inserted into the base
of the metacarpal bone of the
index finger, its radial side.
Relations. By its superfi-
cial surface, with the Supi-
nator longus and fascia of the
fore-arm. Its outer side,
is crossed obliquely by the
Extensor ossis metacarpi pol-
licis and the Extensor primi
internodii pollicis; and at the
wrist by the Extensor secundi
internodii pollicis. By its
deep surface, with the elbow-
joint, the Extensor carpi ra-
dialis brevior, and back part
of the wrist.
The Extensor Carpi Ra-
dialis Brevior is shorter, as
its name implies, and thicker
than the preceding muscle,
beneath which it is placed.
It arises from the external
condyle of the humerus by a
tendon common to it and the
other extensor muscles; from
the external lateral ligament
of the elbow-joint; from a
strong aponeurosis which co-
vers its surface; and from the
intermuscular septum between
it and the adjacent muscles.
The fibres pass downwards,
and terminate about the mid-
dle of the fore-arm in a flat
tendon, which is closely con-
nected with that of the pre-
ceding muscle, accompanies it
to the wrist, lying in the same
groove on the posterior surface
of the radius; passes beneath
the annular ligament, and di-
verging somewhat from its
fellow, is inserted into the
base of the metacarpal bone
of the middle finger, its radial
side.
The tendons of the two
preceding muscles, as they
pass across the same groove
at the back of the radius, are
s 2
26o MUSCLES AND FASCIA.
retained in it by a fibrous sheath, kibricated by a single synovial membrane,
but separated from each other by a small vertical ridge of bone.
Relations. By its superficial surface, with the Extensor carpi radialis longior,
and crossed by the Extensor muscles of the thumb. By its deep surface, with the
Supinator brevis, tendon of the Pronator radii teres, radius and wrist-joint. By
its ulnar border, with the Extensor communis digitorum.
Posterior Brachial Region.
Superficial Layer.
Extensor Communis Digitorum. Extensor Carpi Ulnaris.
Extensor Minimi Digiti. Anconeus.
The Extensor Communis Digitorum is situated at the back part of the fore-arm.
It arises from the external condyle of the humerus by a tendon common to it and
the other superficial Extensor muscles, from the deep fascia, and the inter-
muscular septa between it and the adjacent muscles. Just below the middle
of the fore-arm it divides into four tendons, which pass in a separate sheath be-
neath the posterior annular ligament of the wrist, lubricated by a synovial mem-
brane. The tendons then diverge, the two middle ones passing along the dorsal
surface of the corresponding metacarpal bones, the lateral ones crossing obliquely
to the metacarpal bones, along which they pass; and are finally inserted into the
second and third phalanges of the fingers in the following manner. Each tendon
opposite its correspondmg metacarpo-phalangeal articulation becomes narrow and
thickened, being reinforced by the tendons of the, interossei and lumbricales, gives
ofi" a thin fasciculus upon each side of the joint, and spreads out into a broad
aponeurosis, which covers the whole of the dorsal surface of the first phalanx.
Opposite the first phalangeal joint, this aponeurosis divides into three slips, a
middle and two lateral; the former is inserted into the base of the second phalanx,
and the two lateral, which are continued onwards along the sides of the second
phalanx, unite by their contiguous margins, and are inserted into the upper sur-
face of the last phalanx. The tendons of the middle, ring, and little fingers are
connected together as they cross the hand by small oblique tendinous slips. The
tendons of the index and little fingers also receive, before their division, the special
extensor tendons belonging to them.
Helations. By its superficial surface, with the fascia of the fore-arm and hand,
the posterior annular ligament and integument. By its deep surface, with the
Supinator brevis, the Extensor muscles of the thumb and index finger, posterior
interosseous artery and nerve, the wrist-joint, carpus, metacarpus, and phalanges.
By its radial border, with the Extensor carpi radialis brevior. By its ulnar bor-
der, with the Extensor minimi digiti, and Extensor carpi ulnaris.
The Extensor Mi?iimi Digiti is a small slender muscle, placed on the inner side
of the Extensor communis, with which it is generally connected. It arises from
the common tendon of origin of the Extensor muscles by a thin tendinous slip;
and from the inter-muscular septa between it and the adjacent muscles. Passing
down to the lower extremity of the ulna, its tendon runs through a separate
sheath in the annular ligament, and at the metacarpo-phalangeal articulation
unites with the tendon derived from the long Extensor. The common tendon
then spreads into a broad aponeurosis, which is inserted into the second and third
phalanges of the little finger in a similar manner to the common extensor tendons
of the other fingers.
The Extensor Carpi Ulnaris is the most superficial muscle on the ulnar side of
the fore-ai-m. It arises by the common tendon from the external condyle of the
humerus, from the middle third of the posterior border of the ulna below the An-
coneus, and from the fascia of the fore-arm. This muscle teniiinates in a tendon,
which runs through a groove behind the styloid process of the ulna, passes through
POSTERIOR BRACHIAL REGION. 261
a separate sheath in the annular ligament, and is inserted into the base of the
metacarpal bone of the little finger.
Relations. By its superficial surface, with the fascia of the fore-arm. By its
deep surface, with the ulna, and the muscles of the deep layer.
The Anconeus is a small triangular muscle, placed behind and beneath the
elbow-joint, and appears to be a continuation of the external portion of the
Triceps. It arises by a separate tendon from the back part of the outer condyle
of the humerus; the fibres diverge from this origin, the upper ones being directed
horizontally, the lower obliquely inwards, to be inserted into the triangular surface
at the upper part of the j)osterior surface of the shaft of the ulna.
Relations. By its superficial surface, with a strong fascia derived from the Tri-
ceps. By its deep surface, with the elbow-joint, the orbicular ligament, the ulna,
and a small portion of the Supinator brevis.
Posterior Brachial Region.
Deep Layer.
Supinator Brevis. Extensor Primi Internodii Pollicis.
Extensor Ossis Metacarpi Pollicis. Extensor Secundi Internodii Pollicis.
Extensor Indicis.
The Supinator Brevis is a broad muscle, of a hollow cylindrical form, curved
around the upper third of the radius. It arises from the external condyle of the
humerus, from the external lateral ligament of the elbow-joint, from the orbicular
ligament of the radius, from the prominent oblique line of the ulna, extending
down from the lower extremity of the lesser sigmoid cavity, and the triangular
depression in front of it; it also arises from a tendinous expansion which covers
its surface. The fibres of the muscle pass obliquely around the upper part of the
radius; the most superior fibres forming a sling-like fasciculus, which passes around
the neck of the radius above the tuberosity, to be attached to the back part of its
Mnner surface; the middle fibres being attached to the outer edge of the bicipital
Ituberosity; the lower fibres to the oblique line as low down as the insertion of the
IPronator radii teres. This muscle is pierced by the posterior interosseous nerve.
Relations. By its superficial surface, with the Pronator radii teres, all the su-
perficial Extensor and Supinator muscles, the Anconeus, the radial vessels and
lerve, and the musculo-sj)iral nerve. By its deep surface, with the elbow joint,
the interosseous membrane, and the radius.
The Extensor Ossis Metacarpi Pollicis is the most external and the largest
^of the deep Extensor muscles, lying immediately below the Supinator brevis.
[t arises from the posterior surface of the shaft of the ulna below the origin
'of the Supinator brevis, from the interosseous ligament, and from the middle
third of the posterior surface of the shaft of the radius. Passing obliquely down-
wards and outwards, it terminates in a tendon which runs through a groove on the
outer side of the styloid process of the radius, accompanied by the tendon of the
Extensor primi internodii pollicis, and is inserted into the base of the metacarpal
bone of the thumb.
Relations. By its superficial surface, with the Extensor communis digitorum.
Extensor minimi digiti, and fascia of the fore-arm; being crossed by the branches
of the posterior interosseous artery and nerve. By its deep surface, with the
ulna, interosseous membrane, radius, the tendons of the Extensor carpi radialis
longior and brevior, and at the outer side of the wrist with the radial artery. By
its upper border, with the Supinator brevis. By its lower border, with the Ex-
tensor primi internodii pollicis.
The Extensor Primi Internodii Pollicis is much smaller than the preceding
muscle, on the inner side of which it lies. It arises from the posterior surface of
the shaft of the radius, immediately below the Extensor ossis metacarpi, and
from the interosseous membrane. Its direction is similar to that of the Exten-
sor ossis metacarpi, its tendon passing through the same groove on the outer side
262
MUSCLES AND FASCIA.
of the styloid process, to be inserted into the base of the first phalanx of the
thumb.
Relations. The same as those of the Extensor ossis metacarpi pollicis.
The Extensor Secundi Internodii Pollicis is much larger than the preceding
muscle, the origin of which
158.— Posterior Surface of the Fore-arm. Deep Muscles. ^* P^^'^^J covers in. It arises
from the posterior surface of
the shaft of the ulna, below
the origin of the Extensor
ossis metacarpi pollicis, and
from the interosseous mem-
brane. It terminates in a
tendon which passes through
a distinct canal in the annu-
lar ligament, lying in a nar-
row oblique groove at the
back part of the lower end of
the radius. It then crosses
obliquely the tendons of the
Extensor carpi radialis lon-
gior and brevier, being sepa-
rated by a triangular interval
from the other Extensor ten-
dons of the thumb, in which
space the radial artery is
found; and is finally inserted
into the base of the last
phalanx of the thumb.
Relations. By its super-
ficial surface, with the same
parts as the Extensor ossis
metacarpi pollicis. By its
deep surface, with the ulna,
interosseus membrane, radius,
the wrist, the radial artery,
and metacarpal bone of the
thumb.
The Extensor Indicis is a
narrow elongated muscle,
placed on the inner side of,
and parallel with, the pre-
ceding. It arises from the
posterior surface of the shaft
of the ulna below the origin
of the Extensor secundi inter-
nodii pollicis, and from the
interosseous membrane. Its
tendon passes with the Ex-
tensor communis digitorum
through the same canal in the
annular ligament, and subse-
quently joins that tendon of
the Extensor communis which
belongs to the index finger,
opposite the lower end of
the corresponding metacarpal
bone. It is finally inserted
OF THE HAND. 263
into the second and third phalanges of tlie index finger, in the manner already
described.
Relations. They are similar to those of the preceding muscles.
Nerves. The Supinator longus, Extensor carpi radialis longior, and Anconeus,
are supplied by branches from the musculo-spiral nerve. The remaining muscles
of the radial and posterior brachial regions, by the posterior interosseous nerve.
Actions. The muscles of the radial and jjosterior brachial regions, which com-
prise all the Extensor and Supinator muscles, act upon the fore-arm, w^rist and
hand; they are the direct antagonists of the Pronator and Flexor muscles. The
Anconeus assists the Triceps in extending the fore-arm. The Supinator longus
and brevis are the supinators of the fore-arm and hand; the former muscle more
especially acting as a supinator when the limb is pronated. When supination has
been produced, the Supinator longus, if still continuing to act, Ilexes the fore-arm.
The Extensor carpi radialis longior and brevier, and Extensor carpi ulnaris
muscles, are the Extensors of the wrist; continuing their action, they serve to
extend the fore-arm upon the arm; they are the direct antagonists of the Flexor carpi
radialis and ulnaris. The common Extensor of the fingers, the Extensors of the
thumb, and the Extensors of the index and little fingers, serve to extend the pha-
langes into which they are inserted; and are the direct antagonists of the Flexors.
By continuing their action they assist in extending the fore-arm. The Extensors
of the thumb may assist in supinating the fore-arm, when this part of the hand
has been drawn inwards towards the palm, on account of the oblique direction of
the tendons of these muscles.
Muscles and Fasciae of the Hand.
Dissection (fig.i 30). Make a transverse incision across the front of the wrist, and a second
across the heads of the metacarpal bones, connect the two by a vertical incision in the
middle line, and continue it through the centre of the middle finger. The anterior and
posterior annular ligaments, and the palmar fascia, should first be dissected.
The Anterior Annular Ligament is a strong fibrous band, which arches over
the front of the carpus, converting the deep groove on the front of these bones
into a canal, beneath which the tendons of the muscles of the fore-arm pass, pre-
vious to their insertion into the fingers. This ligament is attached, internally, to
the pisiform bone, and unciform process of the unciform; and externally, to the
tuberosity of the scaphoid, and ridge on the trapezium. It is continuous, above,
with the deep fascia of the fore-arm, and below, with the palmar fascia. It is
crossed by the tendon of the Palmaris longus, by the ulnar artery and nerve, and
the cutaneous branch of the median nerve. It has inserted into its upper and
inner part, the tendon of the Flexor carpi ulnaris; and has, arising from it below,
the small muscles of the thumb and little finger. It is pierced by the tendon of
the Flexor carpi radialis; and, beneath it, pass the tendons of the Flexor sublimis
and profundus digitorum, the Flexor longus pollicis, and the median nerve.
There are two synovial membranes beneath this ligament; one of large size, en-
closing the tendons of the Flexor sublimis and profundus; and a separate one
for the tendon of the Flexor longus pollicis; the latter is also lai'ge and very ex-
tensive, reaching from above the wrist to the extremity of the last phalanx of the
thumb.
The Posterior Annular Ligament is a strong transverse fibrous band, extending
across the back of the wrist, and continuous with the fascia of the fore-arm. It
forms a sheath for the extensor tendons in their passage to the fingers, being
attached, internally, to the cuneiform and pisiform bones, and palmar fascia; ex-
ternally, to the margin of the radius; and in its passage across the wrist, to the
elevated ridges on the posterior surface of the radius. It presents six
compartments for the passage of tendons, each of which is lined by a separate
synovial sac. These are, from within outwards, I. A sheath on the outer side of
the radius for the tendons of the Extensor ossis metacarpi, and Extensor
primi internodii pollicis. 2. Behind the styloid process, for the tendons
264 MUSCLES AND FASCIiE.
of the Extensor carpi radialis longior and brevior. 3. Opposite the middle of the
posterior surface of the radius, for the tendon of the Extensor secundi internodii
pollicis. 4. For the tendons of the Extensor communis digitorum, and Extensor
indicis. 5. For the Extensor minimi digiti. 6. For the tendon of the Extensor
carpi ulnaris. The synovial membranes lining these sheaths are usually very ex-
tensive, extending from above the annular ligament, dow^n upon the tendons, al-
most to their insertion.
The Palmar Fascia foi'ms a common sheath w^hich invests the muscles of the
hand. It consists of three portions, a central and tvi^o lateral. The central por-
tion occupies the middle of the palm, is triangular in shape, of great strength and
thickness, and binds down the tendons in this situation. It is narrow above, being-
attached to the lower margin of the annular ligament, and receives the expanded
tendon of the Palmaris longus muscle. Below, it is broad and expanded, and op-
posite the heads of the metacarpal bones divides into four slips, for the four fingers.
Each slip subdivides into two processes which enclose the tendons of the Flexor
muscles, and are attached to the sides of the first phalanx, and to the anterior or
glenoid ligament; by this arrangement, four arches are formed, under which the
Flexor tendons pass. The arched intervals left in the fascia between these four
fibrous slips, transmit the digital vessels and nerves, and the tendons of the Lum-
bricales. At the point of division of the palmar fascia into the slips above men-
tioned, numerous strong transverse fibres bind the separate processes together.
This fascia is intimately adherent to the integument by numerous fibrous bands,
and gives origin by its inner margin to the Palmaris brevis; it covers the superficial
palmar arch, the tendons of the fiexor muscles, and the branches of the median
and ulnar nerves; and on each side it gives ofi" a vertical septum, which is con-
tinuous with the interosseous aponeurosis, and s¶tes the lateral from the middle
palmar region.
The Lateral portions of the palmar fascia are very thin fibrous layers, which
cover, on the radial side, the muscles of the ball of the thumb; and on the ulnar
side, the muscles of the little finger; they are continuous with the dorsal fascia,
and in the palm, with the middle j)ortion of the palmar fascia.
Muscles of the Hand.
The muscles of the hand are subdivided into three groups. I. Those of the
thumb, which occupy the radial side. 2. Those of the little finger, which occupy
the ulnar side. 3. Those in the middle of the palm and between the interosseous
spaces.
Radial Group.
Muscles of the Thumb.
Abductor Pollicis.
Opponens Pollicis (Flexor Ossis Metacarpi).
Flexor Brevis Pollicis.
Adductor Pollicis.
The Abductor Pollicis is a thin, flat, narrow muscle, placed immediately be-
neath the integument. It arises from the ridge of the os trapezium and annular
ligament; and passing outwards and downwards, is inserted by a thin flat tendon
into the radial side of the base of the first phalanx of the thumb.
Relations. By its superficial surface, with the palmar fascia. By its deep sur-
face, with the Opponens pollicis, from which it is separated by a thin aponeurosis.
Its inner border, is separated from the Flexor brevis pollicis by a narrow cellular
interval.
The Opponens Pollicis {Flexor Ossis Metacarpi) is a small triangular muscle,
placed beneath the preceding. It arises from the palmar surface of the trapezium
and annular ligament; the fleshy fibres pass downwards and outwards, to be inserted
into the whole length of the metacarjDal bone of the thumb on its radial side.
Relations. By its superficial surface, with the Abductor pollicis. By its deep
OF THE HAND.
265
surface, with the trapezio-metacarpal articulation. By its inner border, with the
Flexor brevis pollicis.
The Flexor Brevis Pollicis is much larger than either of the two preceding
muscles, beneath which it is placed. It consists of two distinct portions, in the
interval between which lies the tendon of the Flexor longus pollicis. The ante-
rior and more superficial portion arises from the trapezium and outer two-thirds of
the annular ligament. The deeper portion from the trapezoides, os magnum, base
159. — Muscles of the Left Hand. Palmar Surface.
of the third metacarpal bone, and sheath of the tendon of the Flexor carpi radialis.
The fleshy fibres unite to form a single muscle; this divides into two tendons,
266 MUSCLES AND FASCIA.
which are inserted one on either side of the base of the first phalanx of the thumb.
A sesamoid bone is developed in each of these tendons as they pass across the me-
tacarpo-phalangeal joint; the outer one being joined by the tendon of the Abduc-
tor, and the inner, by that of the Adductor.
Relations. By its superficial surface, with the palmar fascia. By its deep
surface, with the Adductor pollicis, and tendon of the Flexor carpi radialis.
By its external surface, with the Opponens pollicis. By its internal surface, with
the tendon of the Flexor longus pollicis.
The Adductor Pollicis (fig. 156), is the most deeply seated, and the largest of this
group of muscles. It is of a triangular form, arising, by its broad base, from the
whole length of the metacarpal bone of the middle finger on its palmar surface : the
fibres, proceeding outwards, converge, to be inserted by a short tendon into
the ulnar side of the base of the first phalanx of the thumb, and into the internal
sesamoid bone, being blended with the innermost tendon of the Flexor brevis
pollicis.
Relations. By its superficial surface, with the Flexor brevis pollicis, the
tendons of the Flexor profundus digitorum and Lumbricales. Its deep surface,
covers the two first interosseous spaces, from which it is separated by a strong
aponeurosis.
Nerves. The Abductor, Opponens, and outer head of the Flexor brevis pollicis,
are supplied by the median nerve ; the inner head of the Flexor brevis, and the
Adductor pollicis, by the ulnar nerve.
Actions. The actions of the muscles of the thumb are almost sufiS.ciently indi-
cated by their names. This segment of the hand is provided with three Extensors,
an Extensor of the metacarpal bone, an Extensor of the first, and an Extensor of
the second phalanx ; these occupy the dorsal sm'face of the fore-arm and hand.
There are, also, three Flexors on the palmar surface, a Flexor of the metacarpal
bone, the Flexor ossis metacarpi (Opponens pollicis), the Flexor brevis pollicis,
and the Flexor longus pollicis ; there is also an Abductor and an Adductor.
These muscles give to the thumb that extensive range of motion which it pos-
sesses in an eminent degree.
Ulnar Region.
Muscles of the Little Finger.
Palmaris Brevis. Flexor Brevis Minimi Digiti.
Abductor Minimi Digiti. Opponens Minimi Digiti.
The Palmaris Brevis, is a thin quadrilateral plane of muscular fibres, placed
immediately beneath the integument on the ulnar side of the hand. It arises
by tendinous fasciculi, from the annular ligament and palmar fascia ; the fleshy
fibres pass horizontally inwards, to be inserted into the skin on the inner border
of the palm of the hand.
Relations. By its superficial surface, with the integument to which it is inti-
mately adherent, especially by its inner extremity. By its deep surface, with
the inner portion of the palmar fascia, which separates it from the ulnar artery
and nerve, and from the muscles of the ulnar side of the hand.
The Abductor Minimi Digiti is situated on the ulnar border of the palm of the
hand. It arises by tendinous fibres from the pisiform bone, and from an expan-
sion of the tendon of the Flexor carpi ulnaris. The muscle terminates in a
flat tendon, which is inserted into the base of the first phalanx of the little finger,
on its ulnar side.
Relations. By its superficial surface, with the inner portion of the palmar
fascia, and the Palmaris brevis. By its deep surface, with the Flexor ossis meta-
carpi. By its inner border, with the Flexor brevis minimi digiti.
The Flexor Brevis Minimi Digiti lies on the same plane as the preceding
muscle, on its radial side. It arises from the unciform process of the uncifoi'm
OF THE HAND.
267
boue, and anterior surface of the annular ligament, and is inserted into the base
of the first phalanx of the little finger, in connection with the preceding. It
is separated from the Abductor at its origin, by the communicating branch
of the ulnar artery, and deep palmar branch of the ulnar nerve. This muscle is
sometimes wanting. The Abductor is then, usually, of large size.
Relations. By its superficial surface, with the internal portion of the palmar
fascia, and the Palmaris brevis. By its deep surface, with the Flexor ossis me-
tacarpi.
The Opponens Minimi Digiti (fig. 1 5 6), is of a triangular form, and placed im-
mediately beneath the preceding muscles. It arises from the unciform process
of the unciform bone, and contiguous portion of the annular ligament ; from
these points, the fibres pass downwards and inwards, to be inserted into the
whole length of the metacarpal bone of the little finger, along its ulnar margin.
Relations. By its superficial surface, with the Flexor brevis, and Abductor
minimi digiti. By its deep surface, with the interossei muscles in the fifth
metacarpal space, the metacarpal bone, and the Flexor tendons of the little
finger.
Nerves. All the muscles of this group are supplied by the ulnar nerve.
Actions. The actions of the muscles of the little finger are expressed in their
names. The Palmaris brevis corrugates the skin on the inner side of the
palm of the hand.
Middle Palmar Eegion.
Lumbricales. Interossei Palmares.
Interossei Dorsales.
The Lumbricales are four small fleshy fasciculi, accessories to the deep Flexor
muscle. They arise by fleshy fibres from the tendons of the deep Flexor, the
first and second, from the radial side and palmar surface of the tendons of the index
and middle fingers, the third, from the contiguous sides of the tendons of the
middle and ring fingers, and the fourth, from the contiguous sides of the tendons
of the ring and little fingers. They pass forwards to the radial side of the cor-
responding fingers, and opposite the Metacarpo-phalangeal articulations, each
tendon terminates in a broad aponeurosis, 160. — The Dorsal Interossei of Left Hand,
which is inserted into the tendinous ex-
pansion from the Extensor communis di-
gitorum, which covers the dorsal aspect
of each finger.
The Interossei Muscles are so named
from their occupying the intervals be-
tween the metacarpal bones. They are
divided into two sets, a dorsal and pal-
mar, the former are four in number, one
in each metacarpal space, the latter,
three in number, lie upon the metacarpal
bones.
The Dorsal Interossei are four in
number, larger than the palmar, and
occupy the intervals between the meta-
carpal bones. They are bipenniform
muscles, arising by two heads from the
adjacent sides of the metacarpal bones,
but more extensively from that side of
the metacarpal bone, which corresponds
to the side of the finger in which the
muscle is inserted. They are inserted
268
SURGICAL ANATOMY.
into the base of the first phalanges, and mto the aponeurosis of the common
Extensor tendon. Between the double origin .of each of these muscles is a
narrow triangular interval, through which passes a perforating branch from the
deep palmar arch.
The First Dorsal Interosseous muscle or Abductor indicis, is larger than the
others, and lies in the interval between the thumb and index finger. It is flat,
triangular in form, and arises by two heads, separated by a fibrous arch, for the
passage of the radial artery into the deep part of the palm of the hand. The
outer head arises from the upper half of the ulnar border of the first metacarpal
bone, the inner head, from the entire length of the radial border of the second
metacarpal bone, the tendon is inserted into the radial side of the index finger.
The second and third are inserted into the middle finger, the former into its
radial, the latter into its ulnar side. The fourth is inserted in the radial side
of the ring finger.
The Palmar Interossei, three in number, are smaller than the Dorsal, and placed
i6i.— The Palmar Interossei of Left "^V^^ ^^^ palmar surface of the metacarpal
Hand. bones, rather than between them. They
arise from the entire length of the meta-
carpal bone of one finger, and are inserted
into the side of the base of the first pha-
lanx and aponeurotic expansion of the
common Extensor tendon of the same finger.
The first arises from the ulnar side of
the second metacarpal bone, and is inserted
into the same side of the index finger. The
second arises from the radial side of the
fourth metacarpal bone, and is inserted into
the same side of the ring finger. The third
arises from the radial side of the fifth me-
tacarpal bone, and is inserted into the same
side of the little finger. From this account
it may be seen, that each finger is provided
with two Interossei muscles, with the excep-
tion of the little finger.
Nerves. The two outer Lumbricales are
supplied by the median nerve; the rest of
the muscles of this group by the ulnar.
Actions. The Dorsal interossei muscles
abduct the fingers from an imaginary line
drawn longitudmally through the centre of the middle finger, and the Palmar
interossei adduct the fingers towards the same line. They usually assist the
Extensor muscles, but when the fingers are slightly bent, assist in flexing the
fingers.
SURGICAL ANATOMY.
The Student having completed the dissection of the muscles of the upper ex-
tremity, should consider the efifects likely to "be produced by the action of the
various muscles in fracture of the bones ; the causes of displacement are thus
easily recognised, and a suitable treatment in each case may be readily adopted.
In considering the actions of the various muscles upon fractures of the upper
extremity, the most common forms of injury have been selected, both for illus-
tration and description.
Fracture of the clavicle is an exceedingly common accident, and is usually caused
by indirect violence, as a fall upon the shoulder; it occasionally, however, occurs
from direct force. Its most usual situation is just external to the centre of the
bone, but it may occur at the sternal or acromial ends.
Fracture of the middle of the clavicle (fig. 162) is always attended with con-
Of the muscles of the upper extremity.
269
siderable displacement, the outer fragment being drawn downwards, forwards, and
inwards; the inner fragment slightly upwards. The outer fragment is drawn down
by the weight of the arm and the action of
the Deltoid, and forwards and inwards by 162.— Fracture of the Middle of the
the Pectoralis minor and Subclavius muscles ; Clavicle.
the inner fragment is slightly raised by the
Sterno-cleido mastoid, but only to a very
limited extent, as the attachment of the
costo-clavicular ligament and Pectoralis
major below and in front would prevent any
very great displacement upwards. The
causes of displacement having been ascer-
tained, it is easy to apply the appropriate
treatment. The outer fragment is to be
drawn outwards, and, together with the
scapula, raised upwards to a level with the
inner fragment, and retained in that posi-
tion.
In fracture of the acromial end of the
clavicle between the conoid and trapezoid
ligaments, only slight displacement occurs,
as these ligaments, from their oblique inser-
tion, serve to hold both portions of the bone
in apposition. Fracture, also, of the sternal
end, internal to the costo-clavicular ligament,
is attended with only slight displacement,
this ligament serving to retain the fragments
in close apposition.
Fracture of the acromion process usually arises from violence applied to the
upper and outer part of the shoulder: it is generally known by the rotundity of
the shoulder being lost, from the Deltoid drawing downwards and forwards the
fractured portion; and the displacement may easily be discovered by tracing the
mai'gin of the clavicle outwards, when the fragment will be found resting on
the front and upper part of the head of the humerus. In order to relax the
anterior and outer fibres of the Deltoid (the opposing muscle), the arm should
be drawn forwards across the chest, and the elbow well raised up, so that
the head of the bone may press upwards the acromion process, and retain it in its
position.
Fracture of the coracoid process is an extremely rare accident, and is usually
caused by a sharp blow directly on its pointed extremity. Displacement is here
produced by the combined actions of the Pectoralis minor, short head of the
Biceps, and Coraco-brachialis, the former muscle drawing the fragment inwards,
the latter directly downwards, the amount of displacement being limited by the
connection of this process to the acromion by means of the coraco-acromion liga-
ment. In order to relax these muscles, and replace the fragments in close appo-
sition, the fore-arm should be flexed so as to relax the Biceps, and the arm drawn
forwards and inwards across the chest so as to relax the Coraco-brachialis; the
action of the Pectoralis minor may be counteracted by placing a pad in the axilla;
the humerus should then be pushed upwards against the coraco-acromial ligament,
and the arm retained in this position.
Fracture of the anatomical neck of the humerus within the capsular ligament
is a rare accident, attended with very slight displacement, an impaired condition of
the motions of the joint, and crepitus.
Fracture of the surgical neck (fig. 163) is very common, is attended with con-
siderable displacement, and its appearances correspond somewhat with those of
dislocation of the head of the humerus into the axilla. - The upper fragment is
slightly elevated under the coraco-acromion ligament by the muscles attached to
270
SURGICAL ANATOMY.
163. — Fracture of the Surgical Neck
of the Humerus.
the greater and lesser tuberosities; the upper end of the lower ligament is drawn
inwards by the Pectoralis major, Latissimus dorsi, and Teres major; and the
humerus is thrown obliquely outwards from
the side by the action of the Deltoid, and
occasionally elevated so as to project beneath
and in front of the coracoid process. By
fixing the shoulder, and drawing the arm
outwards and downwards, the existing de-
formity is at once reduced. To counteract
the action of the opposing muscles, and to
keep the fragments in position, the arm
should be drawn from the side, and paste-
board splints' applied on its four sides, a
large conical-shaped pad should be placed
in the axilla with the base turned upwards,
and the elbow approximated to the side, and
retained there by a broad roller passed
around the chest; by these means, the action
of the Pectoralis major, Latissimus dorsi.
Teres major, and Deltoid muscles are coun-
teracted: the fore-arm should then be flexed,
and the liand supported in a sling, care
being taken not to raise the elbow, otherwise the lower fragment may be displaced
upwards.
Li fracture of the shaft of the humerus below the insertion of the Pectoralis
major, Latissimus dorsi, and Teres major, and abeve the insertion of the Deltoid,
there is also considerable deformity, the lower end of the upper fragment being
drawn inwards by the first mentioned muscles, and the lower fragment drawn up-
wards and outwards by the Deltoid, producing shortening of the limb, and a con-
siderable prominence at the seat of fracture, from the fractured ends of the bone
riding over one another, especially if the fracture takes place in an oblique direc-
tion. The fragments may be readily brought into apposition by extension from
the elbow, and retained in that position by adopting the same means as in the
preceding injury.
Li fracture of the shaft of the humerus immediately below the insertion of the
Deltoid, the amount of deformity depends greatly upon the direction of the fracture.
If the fracture occurs in a transverse direction, only slight displacement occurs,
the lower extremity of the upper fragment being drawn a little forwards: but in
oblique fracture, the combined actions of the Biceps and Brachialis anticus muscles
in front, and the Triceps behind, draw upwards the lower fragment, causing it to
glide over the lower end of the upper fragment, either backwards or forwards,
according to the direction of the fracture. Simple extension reduces the defor-
mity, and the application of splints on the four sides of the arm retain the frag-
ments in apposition. Care should be taken not to raise the elbow, but the fore-arm
and hand may be supported in a sling.
Fracture of the humerus (fig. 164) immediately above the condyles deserves very
attentive consideration, as the general appearances correspond somewhat with
those produced by separation of the epiphysis of the humerus, and with those of
dislocation of the radius and ulna backwards. If the direction of the fracture
is oblique from above, downwards and outwards, the lower fragment is drawn
upwards and backwards by the Brachialis anticus and Biceps in front, and the
Triceps behind. This injury may be diagnosed from dislocation by the increased
mobility in fracture, the existence of crepitus, and the deformity being remedied
by extension, by the discontinuance of which it is again reproduced. The age of
the patient is of importance in distinguishing this form of injury from separation
of the epiphysis. If fracture occurs in the opposite direction to that shewn in
the plate, the lo'-ver fragment is drawn upwards and forwards, causing a con-
OF THE MUSCLES OF THE UPPER EXTREMITY.
271
siderable prominence in fi'ont, and the lower end of the upper fragment projects
backwards beneath the tendon of the Triceps muscle.
Fracture of the coronoid process of the . t^ , o ,-, tt ■,
'■ '' \ 64. — Jj racture of the Humerus above
the Condyles.
\
ulna is an accident of rai-e occurrence, and
is usually caused by violent action of the
Brachialis anticus muscle. The amount of
displacement varies according to the extent
of the fracture. If the tip of the process
only is broken off, the fragment is drawn
upwards by the Brachialis anticus on a level
with the coronoid depression of the humerus,
and the power of flexion is partially lost. If
the process is broken off near its root, the
fragment is still displaced by the same
muscle; at the same time, on extending the
fore-arm, partial dislocation backwards of the
ulna occurs from the action of the Triceps
muscle. The appropriate treatment would
be to relax the Brachialis anticus by flexing
the fore-arm, and to retain the fragments in
immediate apposition by keeping the arm in
this position. Union is generally liga-
mentous.
Fracture of the olecranon process (fig. 165) is a more frequent accident, and is
caused either by violent action of the Triceps muscle, or by a fall or blow upon the
point of the elbow. The detached fragment is displaced upwards, by the action of
the Triceps muscle, from half an inch
to two inches; the prominence of the 165.— Fracture of the Olecranon.
elbow is consequently lost, and a deep
hollow is felt at the back part of the
joint, which is much increased on
flexing the limb. The patient at the
same time loses the power of extend-
ing the fore-arm. The treatment con-
sists in relaxing the Triceps by ex-
tending the fore-arm, and retaining it
in this position by means of a long
straight splint applied to the front of
the arm; the fragments are thus
brought into closer apposition, and
may be further approximated by draw-
ing down the upper fragment. Union
is generally ligamentous.
Fracture of the neck of the radius
is an exceedingly rare accident, and is generally caused by direct violence. Its
diagnosis is somewhat obscure, on account of the slight deformity visible from the
large number of muscles which surround it; but the movements of pronation and
supination are entirely lost. The upper fragment is drawn outwards by the Supi-
nator brevis, its extent of displacement being limited by the attachment of the
orbicular ligament. The lower fragment is drawn forwards and slightly upwards
by the Biceps, and inwards by the Pronator radii teres, its displacement forwards
and, upwards being counteracted in some degree by the Supinator brevis. The
treatment essentially consists in relaxing the Biceps, Supinator brevis, and Pro-
nator radii teres muscles; by flexing the fore-arm, and placing it in a position
midway between pronation and supination, extension having been previously made
so as to bring the parts in apposition.
Fracture of the radius (fig. 166) is more common than fracture of the ulna, on
272
SURGICAL ANATOMY,
166. — Fracture of the Shaft of the Eadius.
account of the connection of the former with the wrist. Fracture of the shaft of
the radius near its centre may occur from direct violence, but more frequently
from a fall forwards, the entire weight of the body being received on the wrist
and hand. The upper fragment is
drawn upwards by the Biceps, and
inwards by the Pronator radii teres,
holding a position midway between
pronation and supination, and a de-
gree of fulness in the upper half of
the fore-arm is thus produced; the
lower fragment is drawn downwards
and inwards towards the ulna by the
Pronator quadratus, and thrown into
a state of pronation by the same
muscle; at the same time, the Supinator longus, by elevating the styloid process,
into which it is inserted, will serve to depress still more the upper end of the
lower fragment towards the ulna. In order to relax the opposing muscles the
fore-arm should be bent, and the limb placed in a position midway between pro-
nation and stipination; the fracture is then easily reduced by extension from the
wrist and elbow: well padded splints should then be applied on both sides of the
fore-arm from the elbow to the wrist; the hand being allowed to fall, will, by its
own weight, counteract the action of the Pronator quadratus and Supinator longus,
and elevate this fragment to the level of the upper one.
Fracture of the shaft of the ulna is not a common accident; it is usually caused
by direct violence. Its more protected position on the inner side of the limb, the
greater strength of its shaft, and its indirect coi^nection with the wrist, render it
less liable to injury than the radius. It usually occurs a littl^^ below the centre,
which is the weakest part of the bone. The upper fragment retains its usual
position; but the lower fragment is drawn outwards towards the radius by the
Pronator quadratus, producing a well marked depression at the seat of fracture,
and some fulness on the dorsal and palmar surfaces of the fore-arm. The fracture
is easily reduced by extension from the wrist and fore-arm. The fore-arm should
be flexed, and placed in a position midway between pronation and supination, and
well padded splints applied from the elbow to the ends of the fingers.
Fracture of the shafts of the radius and ulna together is not a common acci-
dent; it may arise from a direct blow, or from indirect violence. The lower
fragments are drawn upwards, sometimes forwards, sometimes backwards, according
to the direction of the fracture, by the combined actions of the Flexor and Ex-
tensor muscles, producing a degree of fulness on the dorsal or palmar surface of
the fore-arm; at the same time the two fragments are drawn into contact by the
Pronator quadratus, the radius in a state of pronation : the upper fragment of the
radius is drawn upwards and inwards by the Biceps and Pronator radii teres to a
higher level than the ulna; the upper portion of the ulna is slightly elevated by
the Brachialis anticus. The fracture may be reduced by extension from the wrist
and elbow, and the fore-arm should be placed in the same position as in fracture of
the ulna.
In the treatment of all cases of fracture of the bones of the fore-arm, the greatest
care is requisite to prevent the ends of the bones from being drawn inwards
towards the interosseous space: if this is not carefully attended to, the radius and
ulna may become anchylosed, and the movements of pronation and supination
entirely lost. To obviate this, the splints applied to the limb should be well
padded, so as to press the muscles down into their normal situation in the inter-
osseous space, and so prevent the approximation of the fragments.
Fracture of the lower end of the radius (fig. 167) is usually called Colles frac-
ture, from the name of the eminent Dublin surgeon who first accurately described
it. It usually arises from the patient falling from a height, and alighting upon
the hand, which receives the entire weight of the body. This fracture usually
OF THE MUSCLES OF THE UPPER EXTREMITY.
273
takes place from half an inch to an inch above the articular surface if it occurs in
the adult; but in the child, before the age of sixteen, it is more frequently a sepa-
ration of the epiphysis 'from the apophysis. The displacement which is produced
is very considerable, and bears some resemblance to dislocation of the carpus back-
wards, from which it should be carefully distinguished. The lower fragment is
drawn upwards and backwards behind the upper fragment by the combined actions
167. — Fracture of the Lower End of the Eadius.
of the Supinator longus and the flexors and extensors of the thumb and carpus,
producing a well marked prominence on the back of the wrist, with a deep de-
pression behind. The upper fragment projects forwards, often lacerating the
substance of the Pronator quadratus, and is draAvn by this muscle into close con-
tact with the lower end of the ulna, causing a projection on the anterior surface
of the fore-arm, immediately above the carpus, from the flexor tendons being
thrust forwards. This fracture may be distinguished from dislocation by the
deformity being removed on making sufiicient extension, when crepitus may be
occasionally detected; at the same time, on extension being discontinued, the parts
immediately resume their deformed appearance. The age of the patient will also
assist in determining whether the injury is fracture or separation of the epiphysis.
The treatment consists in flexing the fore-arm, and making powerful extension
from the wrist and elbow, depressing at the same time the radial side of the hand,
and retaining the parts in this position by Avell ])added pistol-shaped splints.
MUSCLES AND FASCIA OF THE LOWER EXTREMITY.
The Muscles of the Lower Extremity are subdivided into groups, corresponding
with the different regions of the limb.
Iliac Region.
Psoas magnus.
Psoas parvus.
Iliacus.
Thigh.
Anterior Femoral Region.
Tensor vaginae femoris.
Sartorius.
Rectus.
Vastus externus.
Vastus internus.
Crurseus.
Subcrurseus.
Internal Femoral Region.
Gracilis.
Pectineus.
Adductor longus.
Adductor brevis.
Adductor magnus.
Hip.
Gluteal Region.
Gluteus maximus.
Gluteus medius.
Gluteus minimus.
Pyriformis.
Gemellus superior.
Obturator internus.
Gemellus inferior.
Obturator externus.
Quadratus femoris.
274
MUSCLES AND FASCIAE.
Posterior Femoral Region.
Biceps.
Semi-tendinosus.
Semi-membranosus.
Leg.
Anterior Tibio-fihidar Region.
Tibialis anticus.
Extensor longus digitorum.
Extensor proprius pollicis.
Peroneus tertius.
Posterior Tihio-fihular Region.
Superficial Layer.
Gastrocnemius.
Plantaris.
Soleus.
Deep Layer.
Popliteus.
Flexor longus pollicis.
Flexor longus digitorum.
Tibialis posticus.
Fibular Region.
Peroneus longus.
Peroneus brevis.
Foot.
Dorsal Region.
Extensor brevis digitorum.
Literossei dorsales.
Plantar Region.
First Layer.
Abductor pollicis.
Flexor brevis digitorum.
Abductor minimi digiti.
Second Layer.
Musculus accessorius.
Lumbricales.
Third Layer.
Flexor brevis pollicis.
Adductor pollicis.
Flexor brevis minimi digiti.
Transversus pedis.
Fourth Layer.
Interossei plantares.
Psoas Ma2:nus.
Iliac Region.,
Psoas Parvus.
Iliac VIS.
Dissection. No detailed description is required for tlie dissection of these muscles.
They are exposed after the removal of the viscera from the abdomen, covered by the Peri-
toneum and a thin layer of fascia, the fascia iliaca.
The Iliac fascia is the aponeurotic layerwhich lines the back partof the abdominal
cavity, and encloses the Psoas and Iliacus muscles throughout their whole extent. It
is thin above, and becomes gradually thicker below, as it approaches the femoral
arch.
The portion investing the Psoas, is attached, above, to the ligamentum arcuatum
internum; internally, to the sacrum; and by a series of arched processes to the
inter- vertebral substances, and prominent margins of the bodies of the vertebrae;
the intervals left opposite the constricted portions of the bodies, transmitting the
lumbar arteries and sympathetic filaments of nerves. Externally, it is continuous
with the fascia lumborum.
The portion investing the iliacus is connected, externally, to the whole length
of the inner border of the crest of the ilium. Internally, to the brim of the true
pelvis, where it is continuous with the periosteum, and receives the tendon of
insertion of the Psoas parvus. External to the femoral vessels, this fascia is
intimately connected with Poupart's ligament, and is continuous with the fascia
transversalis; but corresponding to the point where the femoral vessels pass down
into the thigh, it is prolonged down behind them, forming the posterior wall of the
femoral sheath. Below this point, the iliac fascia surrounds the Psoas and Iliacus
muscles to their termination, and becomes continuous with the iliac portion of the
fascia lata. Internal to the femoral vessels the iliac fascia is connected to the ilio-
pectineal line, and is continuous with the pubic portion of the fascia lata. The
iliac vessels lie in front of the iliac fascia, but all the branches of the lumbar
plexus, behind it; it is separated from the peritoneum by a quantity of loose areolar
tissue. In abcesses accompanying caries of the lower part of the spine, the matter
makes its way to the femoral arch, distending the sheath of the Psoas; and when
it accumulates in considerable quantity, this muscle becomes absorbed, and the
I
ILIAC REGION.
275
nervous cords contained in it are dissected out, and lie exposed in the cavity of
the abscess; tlie femoral vessels, however, remain intact, and the peritoneum seldom
becomes implicated notwithstanding the extreme thinness of this membrane.
Eemove this fascia, and the muscles of the iliac region will be exposed.
The Psoas Magnus is a long fusiform muscle, placed on the side of the lumbar
region of the spine (fig. 169) and margin of the pelvis. It arises from the sides of
the bodies, from the corresponding inter- vertebral substances, and from the anterior
part of the bases of the transverse processes of the last dorsal and all the lumbar
vertebrae. The muscle is connected to the bodies of the vertebrae by five slips, each
of which is attached to the upper and lower margins of two vertebrse, and to the
inter- vertebral substance between them; the slips themselves being connected by
tendinous arches extending across the constricted part of the bodies, beneath which
pass the lumbar arteries and sympathetic nervous filaments. These tendinous
arches also give origin to muscular fibres and protect the blood-vessels and nerves
from pressure during the action of the muscle. The first slip is attached to the
contiguous margins of the last dorsal and first lumbar vertebree; the last, to the
contiguous margins of the fourth and fifth lumbar, and inter- vertebral substance.
From these points, the muscle passes down across the brim of the pelvis, and dimi-
nishing gradually in size, passes beneath Poupart's ligament, and terminates in a
tendon, which after receiving the fibres of the Iliacus, is inserted into the lesser
trochanter of the femur.
Relations. In the lumbar region. By its anterior surface, which is placed
behind the Peritoneum, with the ligamentum arcuatum internum, the kidney, Psoas
parvus, renal vessels, ureter, spermatic vessels, genito-crural nerve, the colon, and
along its pelvic border, with the common and external iliac artery and vein. By
its posterior surface, with the transverse processes of the lumbar vertebrge and the
quadratus lumborum, from which it is separated by the anterior lamella of the apo-
neurosis of the Transversalis ; the anterior crural nerve is at first situated in the
substance of the muscle, and emerges from its outer border at its lower part. The
lumbar plexus is situated in the posterior part of the substance of the muscle.
By its inner side, with the bodies of the lumbar vertebrae, the lumbar arteries, the
sympathetic ganglia, and its communicating branches with the spinal nerves. In
the thigh it is in relation, in front, with the fascia lata; behind, with the capsular
ligament of the hip, from which it is separated by a synovial bursa, which some-
times communicates with the cavity of the joint through an opening of variable
size. By its inner border, with the Pectineus and the femoral artery, which
slightly overlaps it. By its outer border, with the crural nerve and Iliacus muscle.
The Psoas Parvus is a long slender muscle, placed immediately in front of the
preceding. It arises from the sides of the bodies of the last dorsal and first lum-
bar vertebrse, and from the inter-vertebral substance between them. It forms a
small flat muscular bundle, which terminates in a broad flattened tendon, which is
inserted into the ilio-pectineal eminence, being continuous, by its outer border,
with the iliac fascia. This muscle is most frequently found wanting, being pre-
sent, according to M. Theile, in one out of every twenty subjects examined.
Relations. It is covered by the peritoneum, and at its origin by the ligamentum
arcuatum internum; it rests on the Psoas magnus.
The Iliacus is a flat radiated muscle, which fills up the whole of the in-
ternal iliac fossa. It arises from the inner concave surface of the ilium, from
the inner margin of the crest of that bone; behind, from the ilio-lumbar liga-
ment, and base of the saci-um; in front, from the anterior superior and anterior
inferior spinous processes of the ilium, the notch between them, and by a few fibres
from the capsular ligament of the hip-joint. The fibres converge to be inserted
into the outer side of the tendon common to this muscle and the Psoas magnus,
some of them being prolonged down into the oblique line which extends from
the lesser trochanter to the linea aspera.
Relations. Within the pelvis : by its anterior surface, with the iliac fascia,
T 2
276
MUSCLES AND FASCIiE.
which separates this muscle from the peritoneum, and with the external cutaneous
nerve; on the right side, with the caecum; on the left side, with the sigmoid flexure
of the colon. By its posterior surface, with the iliac fossa. By its inner border,
with the Psoas magnus, and anterior crural nerve. In the thigh, it is in relation,
by its anterior surface, with the fascia lata, Rectus and Sartorius; behind, with
the capsule of the hip-joint, a synovial bursa common to it, and the Psoas magnus
being interposed.
Nerves. The Psore muscles are supplied by the anterior branches of the lumbar
nerves. The Iliacus from the anterior crural.
Actions. The Psoas and Iliacus muscles, acting from above, flex the thigh upon
the pelvis, and, at the same time, rotate the femur outwards, from the obliquity
of their insertion into the inner and back part of that bone. Acting from below,
the femur being fixed, the muscles of both sides bpnd the lumbar portion of the
spine and pelvis forwards. They also serve to maintain the erect position, by
supporting the spine and pelvis upon the femur, and assist in raising the trunk
Avhen the body is in the recumbent posture.
The Psoas parvus is a tensor of the iliac fascia.
Anterior Femoral Region.
i63.
Tensor Vaginje Feraoris.
Sartorius.
Rectus.
-Dissection of Lower Extremity.
FroiTt view.
^ 1
i . DtsstetLon
femoral hernia,
Scarpa's triangle
Z. FRONTo/"THICH
"f
■^
/f , DOR.SUMcf FOOT
Vastus Externus.
Vastus In tern us.
Cruraeus.
Sub-Crui'aeus.
Dissection. To expose the muscles and
fascise in this region, an incision should be
made along Poupart's ligament, from the spine
of the ilium to the pubes, from the centre
of this, a vertical incision must be carried
along the middle Hne of the thigh to below
the knee-joint, and connected with a trans-
verse incision, carried from the inner to
the outer side of the leg. The flaps of in-
tegument having been removed, the super-
ficial and deep fasciae should be examined.
The more advanced student would com-
mence the study of this region by an exa-
mination of the anatomy of femoral hernia,
and Scarpa's triangle, the incisions for the
dissection of which are marked out in the
accompanying figure.
Fascia of the Thigh.
The Superficial fascia, forms a con-
tinuous layer over the whole of the
lower extremity, consisting of areolar tis-
sue, containing in its meshes much adipose
matter, and capable of being separated
into two or more layers, between which
are found the superficial vessels and
nerves. It varies in thickness in diflPe-
rent parts of the limb; in the sole of the
foot it is so thin, as to be scarcely demon-
strable, the integument being closely ad-
herent to the deep fascia beneath, but in
the groin it is thicker, and the two layers
are separated from one another by the
superficial inguinal glands, the internal
saphenous vein, and several smaller ves-
sels. Of these two layers, the most
ANTEEIOR FEMORAL REGION.
-77
superficial is continuous above with tlie
superficial fascia of the abdomen, the deep
layer becoming blended Avith the fascia
lata, a little below Poupart's ligament.
The deep layer of superficial fascia is inti-
mately adherent to the margins of the saphe-
nous opening in the fascia lata, and pierced
in this situation by numerous small blood
and lymphatic vessels, hence the name crib-
riform fascia, which has been applied to
it. Subcutaneous bursas are found in the
superficial fascia over the patella, point ot
the heel, and phalangeal articulations of the
toes.
The Deep fascia of the thigh is exposed
on the removal of the superficial fascia, and
is named, from its great extent, the fascia
lata ; it forms a uniform investment for the
whole of this region of the limb, but varies
in thickness in different parts; thus, it is
thickest in the upper and outer side of the
thigh, where it receives a fibrous expansion
from the Gluteus maximus muscle, and the
Tensor vaginae femoris is inserted between
its layers, it is very thin behind, and at
the upper and inner side, where it covers
the Adductor muscles, and again becomes
stronger around the knee, receiving fibrous
expansions from the tendons of the Biceps
externally, and from the Sartorius, Gracilis,
Semitendinosus, and Triceps extensor cruris
in front. The fascia lata is attached, above;
to Poupart's ligament, and crest of the ilium,
behind to the margin of the sacrum and
coccyx, internally to the pubic arch and pec-
tineal line, and below to all the prominent
points around the knee-joint, the condyles
of the femur, tuberosities of the tibia, and
head of the fibula. That portion which
invests the Gluteus medius (the Gluteal
aponeurosis) is very thick and strong, and
gives origin, by its inner surface, to some of
the fibres of that muscle; at the upper bor-
der of the Gluteus maximus, it divides into
two layers; the most superficial, A^ery thin,
covers the surface of the Gluteus maximus,
>and is continuous below with the fascia lata:
the deep layer is thick above, and blends
with the great sacro- sciatic ligament, thin
below, where it separates the Gluteus max-
imus from the deeper muscles. From the
innel" surface of the fascia lata, are given
off" two strong intermuscular septa, which are
attached to the whole length of the linea
aspera; the external and stronger one, ex-
tending from the insertion of the Gluteus
maximus, to the outer condyle, separates
[69.— Muscles of the Iliac and
Femoral Regions.
Aiiieriur
278 MUSCLES AND FASCIJE.
the Vastus externus in front from the short head of the Biceps behind, and gives
partial origin to these muscles ; the inner one, the thinner of the two, separates
the Vastus internus from the Adductor muscles. Besides these, there are nu-
merous smaller septa, separating the individual muscles, and enclosing each in
a distinct sheath. At the upper and inner part of the thigh, a little below
Poupart's ligament, a large oval-shaped aperture is observed in this fascia,
it transmits the internal saphenous vein, and other smaller vessels, and is
termed the saphenous opening. In order more correctly to consider the mode
of formation of this aperture, the fascia lata is described as consisting, in this
part of the thigh, of two portions, an iliac portion, and a pubic portion.
The iliac portion is all that part of the fascia lata placed on the outer side of
the saphenous opening. It is attached, externally, to the crest of the ilium, and its
anterior superior spine, to the whole length of Po\ipart's ligament, as far inter-
nally as the spine of the pubes, and to the Pectineal line in conjunction with
Gimbernat's ligament. From the spine of the pubes, it is reflected downwards
and outwards, forming an arched margin, the superior cornu, or outer boundary of
the saphenous opening ; this margin overlies, and is adherent to the anterior
layer of the sheath of the femoral vessels, to its edge is attached the cribri-
form fascia, and, below, it is continuous with the pubic portion of the fascia lata.
The pubic portion is situated at the inner side of the saphenous opening; at
the lower margin of this aperture it is continuous with the iliac portion ; traced
upwards, it is seen to cover the surface of the Pectineus muscle, and passing
behind the sheath of the femoral vessels, to which it is closely united, is conti-
nuous with the sheath of the Psoas and Iliacus muscles, and is finally lost in the
fibrous capsule of the hip-joint. This fascia is attached above, to the pectineal line in
front of the insertion of the aponeurosis of the external oblique, and internally, to the
margin of the pubic arch. From this description it may be observed, that the
iliac portion of the fascia lata passes in front of the femoral vessels, the pubic
portion behind them, an apparent aperture consequently exists, between the
two, through which the internal saphena joins the femoral vein.
The fascia should now be removed from the surface of the muscles. This may be effected
by pinching it up between the forceps, dividing it, and separating it from each muscle in
the course of its fibres.
The Tensor Vagince Femoris is a short flat muscle, situated at the upper and
outer side of the thigh. It arises by aponeurotic fibres from the anterior part
of the outer lip of the crest of the ilium, and from the outer surface of the an-
terior superior spinous process, between the Gluteus medius, and Sartorius.
The muscle passes obliquely downwards, and a little backwards, to be inserted
by tendinous fibres between the two layers of the fascia lata, about one fourth
down the thigh.
Relations. By its superficial surface, with a layer of the fascia lata and the
integument. By its deep surface, with the deep layer of the fascia lata, the
Gluteus medius, Rectus femoris, and. Vastus externus. By its anterior border,
with the Sartorius, from which it is separated below by a triangular space, in
which is seen the Rectus femoris. By its posterior border, with the Gluteus me-
dius, being separated from it below by a slight interval.
The Sartorius, the longest muscle in the body, is a flat, narrow, riband-like
muscle, which arises by tendinous fibres from the anterior superior spinous process
of the ilium and upper half of the notch below it; it passes obliquely inwards,
across the upper and anterior part of the thigh, then descends vertically, as far
as the inner side of the knee, passing behind the inner condyle of the femur, and
terminates in a tendon, which curving obliquely forwards, expands into a broad
aponeurosis, which is inserted into the upper part of the inner surface of the
shaft of the tibia, nearly as far forwards as the crest. This expansion covers
in the insertion of the tendons of the Gracilis and Semitendinosus, with which
it is partially united, a synovial bursa being interposed between them. An offset
ANTERIOR FEMORAL REGION. 279
is derived from this aponeurosis, whicli blends with the fibi'ous capsule of the knee-
joint, and another, given off from its lower border, blends with the fascia on the
inner side of the leg. The relations of this muscle to the femoral artery should
be carefully examined, as its inner border forms the chief guide in the operation
of including this vessel in a ligature. In the upper third of the thigh, it forms,
with the Adductor longus, the sides of a triangular space, Scarpa's triangle, the
base of which, turned upwards, is formed by Poupart's ligament; the femoral artery
passes perpendicularly through the centre of this space from its base to its apex.
In the middle third of the thigh, the femoral artery lies first along the inner bor-
der, and then beneath the Sartorius.
Relations. By its superficial surface, with the fascia lata and integument.
By its deep surface with the Iliacus, Psoas, Rectus, Vastus internus, sheath of
the femoral vessels, Adductor longus. Adductor magnus, G-racilis, long saphenous
nerve, and internal lateral ligament of the knee-joint.
The Quadriceps Extensor Cruris, includes the four remaining muscles on the
anterior part of the thigh. They are the great Extensor muscles of the leg,
forming a large fleshy mass, which covers the anterior surface and sides of the
femur, being united below into a single tendon, attached to the tibia, and above
subdividing into separate portions, which have received sepai-ate names. Of
these, one occupying the middle of the thigh, connected above with the ilium,
is called the Rectus Femoris, from its straight course. The other divisions lie
in immediate connection with the shaft of the femur, which they cover from the
condyles to the trochanters. The portion on the outer side of the femur being
termed the Vastus Externus, that covering the inner side the Vastus Internus,
and that covering the front of the bone, the Crurceus. The two latter portions
are, however, so intimately blended, as to form but one muscle.
The Rectus Femoris, is situated in the middle of the anterior region of the
thigh; it is fusiform in shape, and its fibres are arranged in a bipenniform man-
ner. It arises by two tendons; one, the straight tendon, from the anterior
inferior spinous process of the ilium, the other is flattened and curves outwards,
to be attached to a groove above the brim of the acetabulum ; this is the reflected
tendon of the Rectus, it unites with the straight tendon at an acute angle, and
then spreads into an aponeurosis, from which the muscular fibres arise. The
muscle terminates in a broad and thick aponeurosis, which occupies the lower
two-thirds of its posterior surface, and, gradually becoming narrowed into a
flattened tendon, is inserted into the patella in common with the Vasti and
Crurteus.
Relations. By its superficial surface, with the anterior fibres of the Gluteus
medius, the Tensor vaginge femoris, Sartorius, and the Psoas and Iliacus, by its
lower three-fourths with the fascia lata. By its posterior surface, with the
hip-joint, the anterior circumflex vessels, and the Cruraeus and Vasti muscles.
The three remaining muscles have been described collectively by some anatomists,
separate from the Rectus, under the name of the Triceps Extensor Cruris ; in
order to expose them, divide the Sartorius and Rectus muscles across the middle,
and turn them aside, when the Triceps extensor will be fully brought into
view.
The Vastus Externus is the largest part of the Quadriceps extensor. It arises
by a broad aponeurosis, which is attached to the anterior border of the great
trochanter, to a horizontal ridge on its outer surface, to a rough line, leading from
the trochanter major to the linea aspera, and to the whole length of the outer
lip of the linea aspera ; this aponeurosis covers the upper three-fourths of the
muscle, and from its inner surface, many fibres arise. A few additional fibres
arise from the tendon of the Gluteus maximus, and from the external inter-
muscular septum between the Vastus externus, and short head of the Biceps.
These fibres form a large fleshy mass, which is attached to a strong aponeurosis,
placed on the under surface of the muscle at its lowest part, this becomes con-
28o MUSCLES AND FASCIA.
tracted and thickened into a flat tendon, which is inserted into the outer part of
the upper border of the patella, blending with the great Extensor tendon.
Relations. By its superficial surface, with the Rectus, the Tensor vaginge
femoris, the fascia lata, and the Gluteus maximus, from which it is separated by
a synovial bursa. By its deep surface, with the Crurgeus, some large branches
of the external circumflex artery being interposed.
The Vastus internus and Crurceus, are so inseparably connected together, as
to form but one muscle. It is the smallest portion of the Quadriceps extensor.
The anterior portion covered by the Rectus, being called the Crurgeus, the internal
portion, which lies immediately beneath the fascia lata, the Vastus Internus. It
arises by an aponeurosis, which is attached to the lower part of the line that
extends from the inner side of the neck of the femur to the linea aspera, from
the whole length of the inner lip of the linea aspera, and internal intermuscular
septum. It also arises from nearly the whole of the internal, anterior and
external surfaces of the shaft of the femur, limited above by the line between
the two trochanters, and extending below to within the lower fourth of the
bone. From these different origins, the fibres converge to a broad aponeurosis,
which covers the anterior surface of the middle portion of the muscle (the
Cruragus), and the deep surface of the inner division of the muscle (the Vastus
internus), becoming joined and gradually narrowing, it is inserted into the patella,
blending with the other portions of the Quadriceps extensor.
Relations. By their superficial surface, with the Psoas and Iliacus, the Rectus,
Sartorius, Pectineus, Adductors, and fascia lata, femoral artery, vein, and saphe-
nous nerve. By its deep surface, with the femur, subcruraeus and synovial
membrane of the knee joint.
The student will observe the striking analogy that exists between the
Quadriceps extensor, and the Triceps brachialis in the upper extremity. So
close is this similarity, that M. Cruvelhier has described it under the name of
the Triceps femoralis. Like the Triceps brachialis, it consists of three distinct
divisions or heads ; a middle or long head, analogous to the long head of the
Triceps, and of two other portions which have respectively received the
names of the external and internal heads of the muscle. These, it will be
noticed, are strictly analogous to the outer and inner heads of the Triceps
brachialis.
The Subcrurceus is a small muscular fasciculus usually distinct from the super-
ficial muscle, which arises from the anterior surface of the lower part of the shaft
of the femur, and is inserted into the upper part of the synovial pouch that
extends upwards from the knee-joint behind the patella. This fasciculus is
occasionally united with the Cruraeus. It sometimes consists of two separate
muscular bundles.
The tendons of the different portions of the Quadriceps extensor unite at the
lower part of the thigh, so as to form a single strong tendon, which is inserted
into the upper part of the patella. More properly speaking, the patella may be
regarded as a sesamoid bone, developed in the tendon of the Quadriceps extensor,
and the ligamentum patellre, which is continued from the lower part of the patella,
to the tuberosity of the tibia, as the proper tendon of insertion of this muscle. A
small synovial bursa is intei-posed between the tendon and the upper part of the tube-
rosity. From the tendons corresponding to the Vasti, a fibrous prolongation is
derived, which is attached below to the upper extremities of the tibia and fibula.
It serves to protect the knee-joint, which is strengthened on its outer side by the
fascia lata.
Nerves. The Tensor vaginae femoris is supplied by the superior gluteal
nerve, the other muscles of this region, by branches from the anterior
crural.
Actions. The Tensor vaginas femoris is a tensor of the fascia lata ; continuing
its action, the oblique direction of its fibres enables it to rotate the thigh inwards.
INTERNAL FEMORAL REGION.
2«I
-Muscles of the Internal Femoral
Region.
In the erect posture, acting from below, it will serve to Bteady the pelvis upon
the head of the femur. The Sartorius flexes the leg upon the thigh, and, con-
tinuing to act, the thigh upon the pelvis, at the same time drawing the limb
inwards, so as to cross one leg over
the other. Taking its fixed point from 170.-
the leg, it flexes the pelvis upon the
thigh, and, if one muscle acts, assists in
rotating it. The Quadriceps extensor
extends the leg upon the thigh. Taking
their fixed point from the leg, as in
standing, the Extensor muscles will act
upon the femur, supporting it perpendi-
cularly upon the head of the tibia,
thus maintaining the entire weight of the
body. The Rectus muscle assists the
Psoas and Iliacus, in supporting the pel-
vis and trunk upon the femur, or in
bending it forwards.
Internal Femoral Region.
Gracilis.
Pectineus.
Adductor Longus.
Adductor Brevis.
Adductor Magnus.
Dissections. These muscles are at once ex-
posed by removing the fascia from the fore
part and inner side of the thigh. The limb
should be abducted so as to render the mus-
cles tense, and easier of dissection.
The Gracilis is the most superficial
muscle on the inner side of the thigh. It
is a thin, flattened, slender muscle, broad
above, narrow and tapering below. It
arises by a thin aponeurosis between two
and three inches in breadth, from the
inner margin of the ramus of the pubes
and ischium. The fibres pass vertically
downwards, and terminate in a rounded
tendon which passes behind the internal
condyle of the femur, and curving around
the inner tuberosity of the tibia, becomes
flattened, and is inserted into the upper
part of the inner surface of the shaft of th6
tibia, beneath the tuberosity. The ten-
don of this muscle is situated immediately
above that of the Semi-tendinosus, and
beneath the aponeurosis of the Sar-
torius, with which it is in part blended.
As it passes across the the internal lateral
ligament of the knee-joint, it is separated
from it by a synovial bursa, common to it
and the Semi-tendinosus muscle.
Relations. By its superficial surface,
with the fascia lata and the Sartorius
282 MUSCLES AND FASCIA.
below; the internal saphena vein crosses it obliquely near its lower part, lying su-
perficial to the fascia lata. By its deep surface, with the three Adductors, and
the internal lateral ligament of the knee-joint.
The Pectineus is a flat quadrangular muscle, situated at the anterior part of the
upper and inner aspect of the thigh. It arises from the linea ilio-pectinea, from
the surface of bone in front of it, between the pectineal eminence and spine
of the pubes, and from a tendinous prolongation of Gimbernat's ligament,
which is attached to the crest of the pubes, and is continuous with the fascia
covering the outer surface of the muscle; the fibres pass downwards, backwards,
and outwards, to be inserted into a rough line leading from the trochanter minor
to the linea aspera.
Relations. By its anterior surface, with the pubic portion of the fascia lata,
which separates it from the femoral vessels and iilternal saphena vein. By its
posterior surface, with the hip-joint, the Adductor brevis and Obturator externus
muscles, the obturator vessels and nerve being interposed. By its outer border,
with the Psoas, a cellular interval separating them, upon which lies the femoral
artery. By its inner border, with the margin of the Adductor longus.
The Adductor Longus, the most superficial of the thi'ee Adductors, is a flat
triangular muscle, lying on the same plane as the Pectineus, with which it is often
blended above. It arises, by a flat narrow tendon, from the front of the pubes, at
the angle of junction of the crest with the symphysis; it soon expands into a broad
fleshy belly, which, passing downwards, backwards, and outwards, is inserted, by
an aponeurosis, into the middle third of the linea aspera, between the Vastus
intern us and the Adductor magnus.
Relations. By its anterior surface, with the fascia lata, and near its insertion,
with the femoral artery and vein. By its posterior surface, with the Adductor
brevis and magnus, the anterior branches of the obturator vessels and nerve, and
with the profunda artery and vein near its insertion. By its outer border, with
the Pectineus. By its inner border, with the Gracilis.
The Pectineus and Adductor longus should now be divided near their origin, and turned
downwards, when the Adductor brevis and Obturator externus will be exposed.
The Adductor Brevis is situated immediately beneath the two preceding muscles.
It is somewhat triangular in form, and arises by a narrow origin from the outer
surface of the descending ramus of the pubes, between the Gracilis and Obturator
externus. Its fibres passing backwards, outwards, and downwards, are inserted by
an aponeurosis into the upper part of the linea aspera, immediately behind the Pec-
tineus and upper part of the Adductor longus.
Relations. By its anterior surface, with the Pectineus, Adductor longus, and
anterior branches of the obturator vessels and nerve. By its posterior surface,
with the Adductor magnus, and posterior branches of the obturator vessels and
nerves. By its outer border, with the Obturator externus, and conjoined tendon of
the Psoas and Iliacus. By its inner border, with the Gracilis and Adductor mag-
nus. This muscle is pierced, near its insertion, by the middle perforating branch
of the profunda artery.
The Adductor brevis should now be cut away near its origin and turned outwards, when
the entire extent of the Adductor magnus will be exposed.
The Adductor Magnus is a large triangular muscle, forming a septum between
the muscles on the inner, and those on the posterior aspect of the thigh. It arises
by short tendinous fibres from a small part of the descending ramus of the pubes,
from the ascending ramus of the ischium, and from the outer margin and under
surface of the tuberosity of the ischium. Those fibres which arise from the ramus
of the pubes are very short, horizontal in direction, and are inserted into the rough
line leading from the great trochanter to the linea aspera, internal to the Gluteus
maximus; those from the ramus of the ischium are directed downwards and out-
wards with different degrees of obliquity, to be inserted by means of a broad apo-
neurosis, into the whole length of the interval between the two lips of the linea
INTERNAL FEMORAL REGION. 283
aspera and upper part of the internal bifurcation below. The internal portion of
the muscle, consisting principally of those fibres which arise from the tuberosity
of the ischium, forms a thick fleshy mass consisting of coarse bundles which
descend almost vertically, and terminate about the lower third of the thigh in a
rounded tendon, which is inserted into the tuberosity above the inner condyle of
the femur, being connected by a fibrous expansion to the line leading upwards from
the condyle to the linea aspera. Between these two portions of the muscle, an
angular interval is left, almost entirely tendinous in structure, for the passage of
the femoral vessels into the popliteal space. The external portion of the muscle
is pierced by four apertures, the three superior for the three perforating arteries;
the fourth, for the passage of the profunda. This muscle gives oif an aponeu-
rosis, which passes in front of the femoral vessels, and joins with the Vastus
internus.
Relations. By its anterior surface, with the Pectineus, Adductor brevis, Ad-
ductor longus and the femoral vessels. By its posterior surface, with the great
sciatic nerve, the Gluteus maximus, Biceps, Semi-tendinosus, and Semi-membra-
nosus. By its superior or shortest border, it lies parallel with the Quadratus
femoris. By its internal or longest border, with the Gracilis, Sartorius, and fascia
lata. By its external or attached border, it is inserted into the femur behind the
Adductor brevis and Adductor longus, which separate it, in front, from the Vastus
internus; and in front of the Gluteus maximus and short head of the Biceps, which
separate it from the Vastus externus.
Nerves. All the muscles of this group are supplied by the obturator nerve.
The Pectineus receives additional branches from the accessory obturator and ante-
rior crural; and the Adductor magnus an additional one from the great sciatic.
Actions. The Pectineus and three Adductors adduct the thigh powerfully; they
are especially used in horse-exercise, the flanks of the horse being firmly grasped
between the knees by the action of these muscles. From their oblique insertion
into the linea aspera, they rotate the thigh outwards, assisting the external Rotators,
and when the limb has been abducted, they draw it inwards, carrying the thigh
across that of the opposite side. The Pectineus and Adductor brevis and longus
assist the Psoas and Iliacus in flexing the thigh upon the pelvis. In progression,
also, all these muscles assist in di'awing forwards the hinder limb. The Gracilis
assists the Sartorius in flexing the leg and drawing it inwards; it is also an Ad-
ductor of the thigh. If the lower extremities are fixed, these muscles may take
their fixed point from below and act upon the pelvis, serving to maintain the body
in the erect posture; or, if their action is continued, to flex the pelvis forwards
upon the femur.
Gluteal Region.
Gluteus Maximus. Gemellus Superior.
Gluteus Medius. Obturator Internus.
Gluteus Minimus. Gemellus Inferior.
Pyriformis. Obturator Externus.
Quadratus Femoris.
Dissection (fig. 171) The subject should be turned on its face, a block placed beneath the
pelvis to make the buttocks tense, and the limbs allowed to hang over the end of the table,
the foot inverted, and the limb abducted. An incision should be made through the integu-
ment along the back part of the crest of the ihum and margin of the sacrum to the tip of
the coccyx, from which point a second incision should be carried obliquely downwards and
outwards to the outer side of the thigh, four inches below the great trochanter. The por-
tion of integument included between these incisions, together with the superficial fascia,
should be removed in the direction shewn in the figure, when the Gluteus maximus and
the dense fascia covering the Gluteus medius will be exposed.
The Gluteus Maximus, the most superficial muscle in the gluteal region, is a
very broad and thick fleshy mass, of a quadrilateral shape, which forms the pro-
minence of the nates. Its large size is one of the most characteristic points in
284
MUSCLES AND FASCIA.
/ , Dissection of
GLUTEAL REGION
the muscular system in man, connected as it is with the power he has of main-
taining the trunk in the erect posture. In structure it is remarkably coarse, being
made up of muscular fasciculi lying parallel with one another, and collected
together into large bundles, separated by deep cellular intervals. It arises from
the superior curved line of the ilium, and the portion of bone, including the ci*est,
immediately behind it; from the posterior surface of the last piece of the sacrum,
the sides of the coccyx, and posterior surface
171.— Dissection of Lower Extremity, f t^e great sacro-sciatic and posterior sacro-
posterior View. iliac ligaments. The fibres are directed ob-
liquely downwards and outwards; those forming
the upper and larger portion of the muscle
(after converging somewhat) terminate in a
thick tendinous lamina, which passes across
the great trochanter, and is inserted into the
fascia lata covering the outer side of the thigh,
the lower portion of the muscle being inserted
into the rough line leading from the great
trochanter to the linea aspera, between the
Vastus externus and Adductor magnus.
Three synovial bursce are usually found se-
parating the under surface of this muscle from
the eminences which it covers. One of these,
of large size, and generally multilocular, sepa-
rates it from the great trochanter. A second,
often wanting, is situated on the tuberosity of
the ischium. A third, between the tendon of
this muscle and the Vastus externus.
Relations. By its superficial surface, with
a thin fascia, which separates it from cellular
membrane, fat, and the integument. By its
deep surface, with the ilium, sacrum, coccyx,
and great sacro-sciatic ligament, the Gluteus
medius, Pyriformis, Gemelli, Obturator inter-
nus, Quadratus femoris, the great sacro-sciatic
foramen, the tuberosity of the ischium, great
trochanter, the Biceps, Semi-tendinosus, Semi-
membranosus, and Adductor magnus muscles, the
gluteal vessels and nerve issuing from the pelvis
above the Pyriformis muscle, ihe ischiatic and
internal pudic vessels and nerves below it. Its
upper border is thin, and connected with the
Gluteus medius by the fascia lata. Its lower
border, free and prominent, forms the fold of the
nates, and is directed towards the perineum.
Dissection. The Gluteus maximus should now be divided near its origin by a vertical
incision carried from its upper to its lower border: a cellular interval will be exposed,
separating it from the Gluteus medius and External rotator muscles beneath. The upper
portion of the muscle should be altogether detached, and the lower portion turned out-
wards; the loose areolar tissue filling up the interspace between the trochanter major and
tuberosity of the ischium being removed, the parts already enumerated as exposed by the
removal of this muscle wiU be seen.
The Gluteus Medius is a broad, thick, radiated muscle, situated on the outer
surface of the pelvis. Its posterior third is covered by the Gluteus maximus; its
anterior two-thirds, is covered by a layer of fascia, which is thick and dense,
and separates it from the integument. It arises from the outer surface of the
ilium, between the superior and middle curved lines, and from the outer lip of
that portion of the crest which is between them; it also arises from the dense
BA.CK of THICB
POPLITEAL SPACE
BACK of LEG
ST
GLUTEAL REGION.
285
fascia covering its outer sur-
face. The fibres gradually
converge to a strong flattened
tendon, which is inserted into
the oblique line which tra-
verses the outer surface of
the great trochanter. A
synovial bursa separates the
tendon of this muscle from
the surface of the trochanter
in front of its insertion.
Relations. By its superfi-
cial surface, with the Gluteus
maximus, Tensor vaginae fe-
moris, and deep fascia. By
its deep surface, with the
Gluteus minimus and the glu-
teal vessels and nerve. Its
anterior border is blended
Avith the Gluteus minimus
and Tensor vaginae femoris.
Its posterior border lies
parallel with the Pyriformis.
This muscle should now be
divided near its insertion and
turned upwards, when the Glu-
teus minimus will be exposed.
The Gluteus Minimus, the
smallest of the three glutei,
is placed immediately beneath
the preceding. It is a fan-
shaped muscle, arising from
the external surface of the
ilium, between the middle and
inferior curved lines, and
behind, from the margin of
the great sacro-sciatic notch;
the fibres converge to the
deep surface of a radiated
aponeurosis, Avhich, terminat-
ing in a tendon, is inserted
into an impression on the an-
terior border of the great tro-
chanter. A synovial bursa is
interposed between the ante-
rior part of the tendon and
the great trochanter.
Relations. By its superfi-
cial surface, with the Gluteus
medius, and the gluteal vessels
and nerves. By its deep sur-
face, with the ilium, the re-
flected tendon of the Rectus
femoris, and capsular liga-
ment of the hip-joint. Its
anterior margin is blended
172. — Muscles of the Gluteal and Posterior
Femoral Regions.
286 MUSCLES AND FASCIA.
with the Gluteus medius. Its posterior margin is often joined with the tendon
of the Pyriformis.
The Pyriformis is a flat muscle, pyramidal in shape, lying almost parallel with
the lower margin of the Grluteus minimus. It is situated partly within the pelvis
at its posterior part, and partly at the back part of the hip-joint. It arises from
the anterior surface of the sacrum by three fleshy digitations, attached to the por-
tions of bone interposed between the second, third, and fourth anterior sacral
foramina, and also from the grooves leading from them: a few fibres also arise
from the margin of the great sacro- sciatic foramen, and from the anterior surface
of the great sacro-sciatic ligament. The muscle passes out of the pelvis through
the great sacro-sciatic foramen, the upper part of which it fills, and is inserted, by
a rounded tendon, into the back part of the upper border of the great trochanter,
being generally blended with the tendon of the Obturator internus.
Relations. By its anterior surface, within the pelvis, with the Rectum (espe-
cially on the left side), the sacral plexus of nerves, and the internal iliac vessels;
external to the pelvis, with the os innominatum and capsular ligament of the hip-
joint. By it^ posterior surface, within the pelvis, with the sacrum; and external
to it, with the Gluteus maximus. By its upper border, with the Gluteus medius,
from which it is separated by the gluteal vessels and nerves. By its loioer border,
with the Gemellus superior; the ischiatic vessels and nerves, and the internal
pudic vessels and nerves, passing from the pelvis in the interval between them.
Dissection. The next muscle, as well as the origin of the Pyriformis, can only be seen
when the pelvis is divided, and the viscera contained in this cavity removed.
The Obturator Internus, like the preceding muscle, is situated partly within
the cavity of the pelvis, partly at the back of the hij)-joint. It arises from the
inner surface of the anterior and external wall 6f the pelvis, being attached to
the margin of bone around the inner side of the obturator foramen; viz., from the
descending ramus of the pubes, and the ascending ramus of the ischium; and,
laterally, from the inner surface of the body of the ischium, between the margin
of the obturator foi-amen in front, the great sciatic notch behind, and the brim of
the true pelvis above. It also arises from the inner surface of the obturator mem-
brane, and from the tendinous arch which protects the obturator vessels and nerve
in passing beneath the sub-pubic arch. The fibres converge downwards and out-
wards, and terminate in four or five tendinous bands, which are found on its deep
surface; these bands are reflected at a right angle over the inner surface of the
tuberosity of the ischium, which is covered with cartilage, grooved for their recep-
tion, and lined with a synovial bursa. The muscle leaves the pelvis by the lesser
sacro-sciatic notch; and the tendinous bands unite into a single flattened tendon,
which passes horizontally outwards, and, after receiving the attachment of the
Gemelli, is inserted into the upper border of the great trochanter in front of the
Pyriformis. A synovial bursa., nai'row and elongated in form, is usually found
between the tendon of this muscle and the capsular ligament of the hip. It occa-
sionally communicates with that between the tendon and the tuberosity of the
ischium, the two forming a single sac.
In order to display the peculiar appearances presented by the tendon of this muscle, it
should be divided near its insertion and reflected outwards.
Relations. Within the pelvis, this muscle is in relation, by its anterior surface,
with the obturator membrane and inner surface of the anterior wall of the pelvis;
by its posterior surface, with the obturator fascia, Avhich separates it from the
Levator ani; and it is crossed by the internal pudic vessels and nerve. This
surface forms the outer boundary of the ischio-rectal fossa. External to the
pelvis, it is covered by the great sciatic nerve and Gluteus maximus, and rests
on the back part of the hip-joint.
The Gemelli are two small muscular fascicvili, accessories to the tendon of the
Obturator internus, which is received into a groove between them. They have
received the names superior and inferior from the position they occupy.
J
GLUTEAL REGION. 287
The Gemellus Superior, the smaller of the two, is a fleshy fasciculus, which
arises from the external surface of the spine of the ischium, and passing horizon-
tally outwards, becomes blended with the upper part of the tendon of the Obturator
internus, and is inserted with it into the superior border of the great trochanter.
This muscle is sometimes wanting.
Relations. By its superficial surface, with the Gluteus maximus and the
ischiatic vessels and nerves. By its deep surface, with the capsule of the hip-
joint. By its upper border, with the lower margin of the Pyriformis. By its
lower border, with the tendon of the Obturator internus.
The Gemellus Inferior arises from the upper part of the outer border of the
tuberosity of the ischium, and, passing horizontally outwards, is blended with the
lower part of the tendon of the Obturator internus, and inserted with it into the
upper border of the great trochanter.
Relations. By its superficial surface, with the Gluteus maximus, and the
ischiatic vessels and nerves. By its deep surface, it covers the capsular ligament
of the hip-joint. By its upper border, with the tendon of the Obturator internus.
By its loiver border, with the tendon of the Obturator externus and Quadratus
femoris.
The Quadratus Femoris is a short flat muscle, quadrilateral in shape (hence its
name), situated immediately below the Gemellus inferior, and above the upper
margin of the Adductor magnus. It arises from the external border of the
tuberosity of the ischium, and proceeding horizontally outwards, is inserted into
the upj)er part of the linea quadrati, on the posterior surface of the trochanter
major, A synovial bursa is often found between the under surface of this muscle
and the lesser trochanter, which it covers.
Relations. By its posterior surface, with the Gluteus maximus and the ischiatic
vessels and nerves. By its anterior surface, with the tendon of the Obturator
externus and Trochanter minor. By its upper border, with the Gemellus inferior.
Its lower border is separated from the Adductor magnus by the internal circumflex
vessels.
Dissection. In order to expose the next muscle (the Obturator ezternus), it is necessary
to remove the Psoas, Iliacus, Pectineus, and Adductor brevis and longus muscles, from the
front and inner side of the thigh ; and the Gluteus maximus and Quadratus femoris, from
the back part. Its dissection should consequently be postponed until the muscles of the
anterior and internal femoral regions have been examined.
The Obturator Externus is a flat triangular muscle, which covers the outer
surface of the anterior wall of the pelvis. It arises from the margin of bone
immediately around the inner side of the obturator foramen, viz., from the body
and ramus of the pubes, and the ramus of the ischium; it also arises from the
inner two-thirds of the outer surface of the obturator membrane, and from the
tendinous arch which completes the sub-pubic canal for the passage of the obturator
vessel and nerve. The fibres converging pass outwards, and terminate in a ten-
don which runs across the back part of the hip-joint, and is inserted into the
digital fossa of the femur.
Relations. By its anterior surface, with the Psoas, Iliacus, Pectineus, Adductor
longus. Adductor brevis, and Gracilis; and more externally, with the neck of the
femur and capsule of the hip-joint. By its posterior surface, with the obturator
membrane and Quadratus femoris.
Nerves. The Gluteus maximus is supplied by the inferior gluteal nerve and a
branch from the sacral plexus. The Gluteus medius and minimus, by the superior
gluteal. The Pyriformis, Gemelli, Obturator internus, and Quadratus femoris, by
branches from the sacral plexus. And the Obturator externus, by the obturator
nerve.
Actions. The Glutei muscles, when they take their fixed point from the pelvis,
are all abductors of the thigh. The Gluteus maximus and the posterior fibres of
the Gluteus medius, rotate the thigh outwards; the anterior fibres of the Gluteus
medius and the Gluteus minimus rotate it inwards. The Gluteus maximus serves
288 MUSCLES AND FASCIA.
to extend the femur, and the Gluteus medius and minimus draw it forwards. The
Gluteus maximus is also a tensor of the fascia lata. Taking their fixed point
from the femur, the Glutei muscles act upon the pelvis, supporting it and the whole
trunk upon the head of the femur, which is especially obvious in standing on one
leg. In order to gain the erect posture after the efibrt of stooping, these muscles
draw the pelvis backwards, assisted by the Biceps, Semi-tendinosus, and Semi-
membranosus muscles. The remaining muscles are powerful rotators of the thigh
outwards. In the sitting posture, when the thigh is flexed upon the pelvis, their
action as rotators ceases, and they become abductors, with the exception of the
Obturator externus, which still rotates the femur outwards. When the femur is
fixed, the Pyriformis and Obturator muscles serve to draw the pelvis forwards if
it has been inclined backwards, and assist in steadying it upon the head of the
femur.
Posterior Febioral Region.
Biceps. Semi-tendinosus. Semi-membranosus.
Dissection (fig. 171). Make a vertical incision along the middle of the thigh, from the lower
fold of the nates to about three inches below the back of the knee-joint, and there connect it
with a transverse incision, carried from the inner to the outer side of the leg. A third inci-
sion should then be made transversely at the junction of the middle with the lower third of
the thigh. The integument having been removed from the back of the knee in the direc-
tion indicated in the figure, and the boundaries and contents of the popliteal space exa-
mined, the removal of the integument from the remaining part of the thigh should be
continued, when the fascia and muscles of this region will be exposed.
The Biceps is a large muscle, of considerable length, situated on the posterior
and outer aspect of the thigh. It arises by two distinct portions or heads. One,
the long head, from an impression at the upper and back part of the tuberosity of
the ischium, by a tendon common to it and the Semi-tendinosus. The femoral or
short head, from the outer lip of the linea aspera, between the Adductor magnus
and Vastus externus, extending from two inches below the Gluteus maximus, to
within two inches of the outer condyle; it also arises from the external inter-
muscular septum. The fibres of the long head form a fusiform belly, which,
passing obliquely downwards and a little outwards, terminates in an aponeurosis
which covers the posterior surface of the muscle, and receives the fibres of the
short head; this aponeurosis becomes gradually contracted into a tendon, which is
inserted into the outer side of the head of the fibula. At its insertion, the tendon
divides into two portions, which embrace the external lateral ligament of the knee-
joint, a strong prolongation being sent forwards to the outer tuberosity of the tibia,
which gives off an expansion to the fascia of the leg. The tendon of this muscle
forms the outer ham-string.
Relations. By its superficial surface, with the Gluteus maximus and fascia lata.
By its deep surface, with the Semi-membranosus, Adductor magnus, and Vastus
externus, the great sciatic nerve, popliteal artery and vein, and near its insertion,
with the external head of the Gastrocnemius, Plantaris, and superior external
articular artery.
The Semitendinosus, remarkable for the great length of its tendon, is situated
at the posterior and inner aspect of the thigh. It arises from the tuberosity of
the ischium by a tendon common to it and the long head of the Biceps; it also
arises from an aponeurosis which connects the adjacent surfaces of the two muscles
to the extent of about three inches after their origin. It forms a fusiform muscle
which, passing downwards and inwards, terminates a little below the middle of
the thigh in a long round tendon, which lies along the inner side of the popliteal
space, curving around the inner tuberosity of the tibia, to be inserted into the
upper part of the inner surface of the shaft of this bone, nearly as far forwards
as its anterior border. This tendon lies beneath the expansion of the Sartorius,
and below that of the Gracilis, to which it is united. A tendinous intersection is
usually observed about the middle of this muscle.
Relations. By its superficial surface, with the Gluteus maximus and fascia lata.
POSTERIOR FEMORAL REGION. 289
By its deep surface, with the Semi-membranosus, Adductor magnus, inner head of
the G-astrocnemius, and internal lateral ligament of the knee-joint.
The Semi-membranosus, so called from the tendinous expansion on its anterior
and posterior surfaces, is situated at the back part and inner side of the thigh.
It arises by a thick tendon from the upper and outer part of the tuberosity of the
ischium above and to the outer side of the Biceps and Semi-tendinosus, and
is inserted into the posterior part of the inner tuberosity of the tibia, beneath
the internal lateral ligament. The tendon of this muscle at its insertion divides
into three portions; the middle portion is the fasciculus of insertion into the back
part of the inner tuberosity, it sends down an expansion to cover the Popliteus
muscle. The internal portion is horizontal, passing forwards beneath the internal
lateral ligament, to be inserted into a groove along the inner side of the internal
tuberosity. The posterior division passes upwards and backwards, to be inserted
into the back part of the outer condyle of the femur, forming the chief part of the
posterior ligament of the knee-joint.
The tendon of origin of this muscle expands into an aponeurosis, which covers
the upper part of its anterior surface; from this muscular fibres arise, and con-
verge to another aponeurotic expansion, which covers the lower part of its posterior
surface, and this contracts into the tendon of insertion. The tendons of the two
preceding muscles, with those of the Gracilis and Sartorius, form the inner ham-
string.
Relations. By its superficial surface, with the Gluteus maximus, Semi-tendi-
nosus, Biceps, and fascia lata. By its deep surface, with the Quadratus femoris.
Adductor magnus, and inner head of the Gastrocnemius. It covers the popliteal
artery and vein, and is separated from the knee-joint by a synovial membrane.
By its inner border, with the Gracilis. By its outer border, with the great
sciatic nerve.
Nerves. The muscles of this region are supplied by the great sciatic nerve.
Actions. The three ham-string muscles flex the leg upon the thigh. When the
knee is semi-flexed, the Biceps, from its oblique direction downwards and out-
wards, rotates the leg slightly outwards; and the Semi-membranosus, in consequence
of its oblique direction, rotates the leg inwards, assisting the Popliteus. Taking
their fixed point from below, these muscles serve to support the pelvis upon the
head of the femur, and to draw the trunk directly backwards, as is seen in feats
of strength, when the body is thrown backwards in the form of an arch.
Surgical Anatomy. The tendons of these muscles occasionally require subcutaneous
division in some forms of spurious anchylosis of the knee-joint, dependent upon permanent
contraction and rigidity of the flexor muscles, or from stiff"ening of the ligamentous and
other tissues surrounding the joint, the result of disease. This is easily effected by putting
the tendon upon the stretch, and inserting a narrow sharp-pointed knife between it and
the skin ; the cutting edge being then turned towards the tendon, it should be divided,
taking care that the wound in the skin is not at the same time enlarged. This operation
has been attended with considerable success in some cases of stiffened knee from rheuma-
tism, gradual extension being kept up for some time after the operation.
Muscles and Fascia of the Leg.
Dissection (fig. 168). The knee should be bent, a block placed beneath it, and the foot
kept in an extended position ; an incision should then be made through the integument in
the middle line of the leg to the ankle, and continvied along the dorsum of the foot to the
toes. A second incision should be made transversely across the ankle, and a third in the
same direction across the bases of the toes: the flaps of integument included between
these incisions should be removed, and the fascia of the leg examined.
The ■ Fascia of the Leg forms a complete investment to the whole of this
region of the limb, excepting to the inner surface of the tibia, to which it is un-
attached. It is continuous above with the fascia lata, receiving an expansion
from the tendon of the Biceps on the outer side, and from the tendons of the
Sartorius, Gracilis, and Semi-tendinosus on the inner side; in front it blends
with the periosteum covering the tibia and fibula; below, it is continuous with
u
ago
MUSCLES AND FASCIA.
the annular ligaments of the ankle. It is
thick and dense in the upper and anterior
part of the leg, and gives attachment, by its
inner surface, to the Tibialis anticus and Ex-
tensor longus digitorum muscles; but thinner
behind, where it covers the Grastrocnemius and
Soleus muscles. Its inner surface gives off, on
the outer side of the leg, two strong inter-
muscular septa, which enclose the Peronsei
muscles, and separate them from those on the
anterior and posterior tibial regions, and several
smaller and more slender processes enclose
the individual muscles in each region; at
the same time, a broad transverse intermus-
cular septum intervenes between the superficial
and deep muscles in the posterior tibio-fibular
region.
The fascia should now be removed by dividing it
in the same direction as the integument, excepting
opposite the ankle, where it should be left entire.
The removal of the fascia should be commenced
from below, opposite the tendons, and detached in
the line of direction of the muscular fibres.
Muscles of the Leg.
These may be subdivided into three groups:
those on the anterior, those on the posterior,
and those on the outer side.
Anterior Tibio-Fibular Region.
Tibialis Anticus.
Extensor Proprius Pollicis.
Extensor Longus Digitorum.
Peroneus Tertius.
The Tibialis Anticus is situated on the outer
side of the tibia, being thick and fleshy at its
upper part, tendinous below. It arises from
the outer tuberosity and upper two-thirds of
the external surface of the shaft of the tibia;
from the adjoining part of the interosseous
membrane; from the deep fascia of the leg;
and from the intermuscular septum between it
and the Extensor communis digitorum: the
fibres pass vertically downwards, and terminate
in a tendon, which is apparent on the anterior
surface of the muscle at the lower third of the
leg. After passing through the innermost
compartment of the anterior annular ligament,
it is inserted into the inner side of the internal
cuneiform bone, and base of the metatarsal
bone of the great toe.
Relations. By its anterior surface, with the
deep fascia, and with the annular ligament.
By its posterior surface, with the interosseous
membrane, tibia, and ankle-joint. By its inner
surface, with tlie tibia. By its otiter surface,
with the Extensor longus digitorum, and
173. — Muscles of the Front of
the Leg.
BH
Tllii
ANTERIOR TIBIO-FIBULAR REGION. 291
Extensor proprins pollicis, the anterior tibial vessels and nerve lying between it
and the last mentioned muscles.
The Extensor Proprius Pollicis is a thin, elongated, and flattened muscle,
situated between the Tibialis anticus and Extensor longus digitorum. It arises
from the anterior surface of the fibula for about the two middle fourths of its
extent, its origin being internal to the Extensor longus digitorum; it also arises
from the interosseous membrane to a similar extent. The fibres pass down-
wards, and terminate in a tendon, which occupies the anterior border of the
muscle, passes through a distinct compartment in the annular ligament, and is
inserted into the base of the last phalanx of the great toe. Opposite the metatarso-
phalangeal articulation, the tendon gives off a thin prolongation on each side,
which covers its surface.
Relations. By its anterior border, with the deep fascia of the leg, and the
anterior annular ligament. By its posterior border, with the interosseous mem-
brane, fibula, tibia, ankle-joint, and Extensor brevis digitorum. By its outer
side, with the Extensor longus digitorum above, the dorsalis pedis artery and
anterior tibial nerve below. By its inner side, with the Tibialis anticus, and the
anterior tibial vessels above.
The Extensor Longus Digitorum is an elongated, flattened, semi-penniform
muscle, situated the most external of all the muscles on the fore-part of the leg.
It arises from the outer tuberosity of the tibia; from the upper three-fourths of
the anterior surface of the shaft of the fibula; from the interosseous membrane,
deep fascia; and from the intermuscular septa between it and the Tibialis anticus
on the inner, and the Peronei on the outer side. The fibres pass downwards, and
terminate in four tendons, v/hich pass through a distinct canal in the annular liga-
ment, together with the Peroneus tertius, run across the dorsum of the foot, and
are inserted into the second and third phalanges of the four lesser toes. The
mode in which these tendons are inserted is the following. Each tendon opposite
the metatarso-phalangeal articulation is joined on its outer side by a tendon of
the Extensor brevis digitorum (except the fourth), and receives a fibrous expansion
from the Interossei and Lumbricales; it then spreads into a broad aponeurosis,
which covers the dorsal surface of the first phalanx: this aponeurosis, at the
articulation of the first with the second phalanx, divides into three slips, a middle
one, which is inserted into the base of the second phalanx, and two lateral slips,
which, after uniting on the dorsal surface of the second phalanx, are continued
onwards to be inserted into the base of the third.
Relations. By its anterior surface, with the deep fascia of the leg, and the
annular ligament. By its posterior surface, with the fibula, interosseous mem-
brane, ankle-joint, and Extensor brevis digitorum. By its inner side, with the
Tibialis anticus, Extensor proprius pollicis, and anterior tibial vessels and nerve.
By its outer side, with the Peroneus longus and brevis.
The Peroneus Tertius is but a part of the Extensor longus digitorum, being
almost always intimately united with it. It arises from the lower fourth of the
anterior surface of the fibula; its outer part, from the lower part of the inter-
osseous membrane; and from an intermuscular septum between it and the Pero-
neus brevis. Its tendon, after passing through the same canal in the annular
ligament as the Extensor longus digitorum, is inserted into the base of the meta-
tarsal bone of the little toe on its dorsal surface.
This muscle is often wanting.
Nerves. These muscles are supplied by the anterior tibial nerve.
Actions. The Tibialis anticus and Peroneus tertius are the direct flexors of the
tarsus upon the leg; the former muscle, from the obliquity in the direction of
its tendon, raises the inner border of the foot; and the latter, acting with the
Peroneus brevis and longus, will draw the outer border of the foot upwards and
the sole outwards. The Extensor longus digitorum and Extensor proprius pollicis
extend the phalanges of the toes, and continuing their action, flex the tarsus upon
the leg. Taking their origin from below, in the erect posture, all these muscles
u 2
2g2
MUSCLES AND FASCIA.
serve to fix the bones of the leg in a perpendicular direction, and give increased
strength to the ankle-joint.
POSTEKIOR TiBIO-FlBULAR EeGION.
Dissection (fig. 171). Make a vertical incision along the middle line of the back of the
leg, from the lower part of the popliteal space to the heel, connecting it below by a trans-
verse incision extending between the two malleoli; the flaps of integument being removed,
the fascia and muscles should be examined.
174. — Muscles of the Back of the Leg.
Superficial Layer.
The muscles in this region of the leg are
subdivided into two layers, superficial and
deep. The superficial layer constitutes a
powerful muscular mass, forming what is
called the calf of the leg. Their large size
is one of the most characteristic features of
the muscular apparatus in man, and bears a
direct connection with his ordinary attitude
and mode of progression.
Superficial Layer.
Gastrocnemius. Soleus.
Plantaris,
The Gastrocnemius is the most superficial
muscle at the back part of the leg, and
forms the greater part of the calf. It
arises by two heads, which are connected
to the condyles of the femur by two
strong flat tendons. The inner head, the
larger, and a little the most posterior, is
attached to a depression at the upper and
back part of the inner condyle. The outer
head, to the upper and back part of the
external condyle, immediately above the
origin of the Popliteus. Both heads, also,
arise by a few tendinous and fleshy fibres
from the ridges which are continued up-
wards from the condyles to the linea aspera.
Each tendon spreads into an aponeurosis,
which covers the posterior surface of that
portion of the muscle to which it belongs;
that covering the inner head being longer
and thicker than the outer. From the an-
terior surface of these tendinous expansions
muscular fibres are given off"; those in the
median line, which correspond to the acces-
sory portion of the muscle derived from the
bifurcations of the linea aspera, unite at an
angle upon a median tendinous raphe below.
The remaining fibres converge to the poste-
rior surface of an aponeurosis which covers
the front of the muscle, and this, gradually
contracting, unites with the tendon of the
Soleus, and forms with it the tendo Achillis.
Relations. By its superficial surface,
with the fascia of the leg, which sepa-
rates it from the external saphenous vein
and nerve. By its deep surface, with the
POSTERIOR TIBIO-FIBULAR REGION.
293
posterior ligament of the knee-joint, the Popliteus, Soleus, Plantaris, popliteal
vessels, and internal popliteal nerve. The tendon of the inner head corresponds
with the back part of the inner condyle, from which it is separated by a synovial
bursa, which in some cases communicates with the cavity of the knee-joint. The
tendon of the outer head contains a sesamoid fibro-cartilage (rarely osseous), where
it plays over the corresponding outer condyle; and one is occasionally found in the
tendon of the inner head.
The Gastrocnemius should be divided across just below its origin, and turned down-
wards, in order to expose the next muscles.
The Soleus is a broad flat muscle, situated immediately beneath the preceding,
It has received its name from the fancied resemblance it bears to a sole-fish. It
arises by tendinous fibres from the back part of the head, and from the upper half
of the posterior surface of the shaft of the fibula, from the oblique line of the tibia,
and from the middle third of its internal border; some fibres also arise from a
tendinous arch which passes between the tibial and fibular origins of the muscle,
and beneath which the posterior tibial vessels and nerve pass into the leg. The
fibres pass backwards to an aponeurosis which covers the posterior surface of the
muscle, and this, gradually becoming thicker and narrower, joins with the tendon
of the Gastrocnemius, and forms with it the tendo Achillis.
Relations. By its superficial surface, with the Gastrocnemius and Plantaris.
By its deep surface, with the Flexor longus digitorum. Flexor longus pollicis.
Tibialis posticus, and posterior tibial vessels and nerve ; from which it is separated
by the transverse intermuscular septum, interposed between the superficial and
deep muscles at the back of the leg.
The Tendo Achillis, the common tendon of the Gastrocnemius, Soleus, and
Plantaris, is the thickest and strongest tendon in the body. It is about six inches
in length, and formed by the junction of the aponeuroses of the two preceding
muscles. It commences about the middle of the leg, but receives fleshy fibres
much lower on its anterior surface. Gradually becoming contracted below, it is
inserted into the lower part of the posterior tuberosity of the os calcis, a synovial
bursa being interposed between the tendon and the upper part of the tuberosity.
Externally it is covered by the fascia and the integument, and it is separated
beneath from the deep seated muscles and vessels, by a considerable interval filled
up with areolar and adipose tissue.
The Plantaris is an extremely diminutive muscle, placed between the Gastroc-
nemius and Soleus, and remarkable for the long and delicate tendon which it
presents. It arises from the lower part of the external bifurcation of the linea
aspera, and from the posterior ligament of the knee-joint. It forms a small fusi-
form belly, about two inches in length, which terminates in a long and slender
tendon, which crosses obliquely between the two muscles of the calf, and running
along the inner border of the tendo Achillis, is inserted with it into the poste-
rior part of the os calcis. This muscle is occasionally double, it is sometimes
wanting. Occasionally its tendon is lost in the subcutaneous adipose tissue, or in
the internal annular ligament.
Nerves, These muscles are supplied by the internal popliteal nerve.
Actions. The muscles of the calf possess considerable power, and are constantly
called into use in standing, walking, dancing, and leaping, hence the large size
they usually present. In walking, these muscles draw powerfully upon the os
calcis, raising the heel, and, with it, the entire body, from the ground; the body
being thus supported on the raised foot, the opposite limb can be carried forwards.
In standing, the Soleus, taking its fixed point from below, steadies the leg upon
the foot, and prevents the body from falling forwards, to which there is a constant
tendency from the super-incumbent weight. The Gastrocnemius, acting from
below, serves to fiex the femur upon the tibia, assisted by the Popliteus. The
Plantaris is the rudiment of a large muscle which exists in some of the lower
animals, and serves as a tensor of the plantar fascia.
294
MUSCLES AND FASCIA.
175. — Muscles of the Back of the Leg,
Deep Layer.
Femu7^\\
Iw
Posterior Tibio-Fibular Region.
Deep Layer.
Popliteus. Flexor Longus Digitorum.
Flexor Longus Pollicis. Tibialis Posticus.
Dissection. Detach the Soleus from its attachment to the fibula and tibia, and turn it
downwards, when the deep layer of muscles is
exposed, covered by the deep fascia of the leg.
The deej) fascia of the leg is a broad,
transverse inter-muscular septum, interposed
between the superficial and deep muscles,
in the^ posterior tibio-fibular region. On
each side it is connected to the margins of
the tibia and fibula. Above, where it covers
the Popliteus, it is thick and dense, and
receives an expansion from the tendon of
the Semi-membranosus; it is thinner in the
middle of the leg, but, below, where it
covers the tendons passing behind the mal-
leoli, it is thickened. It is continued on-
wards in the interval between the ankle and
the heel, where it covers the vessels and
is blended with the internal annular liga-
ment.
This fascia should now be removed, com-
mencing from below opposite the tendons, and
detaching it "from the muscles in the direction of
their fibres.
The Popliteus is a thin, flat, triangular
muscle, which forms the floor of the popli-
teal space, and is covered in by a tendinous
expansion, derived from the Semi-membra-
nosus muscle. It arises by a strong flat
tendon, about an inch in length, from a deep
depression on the outer side of the external
condyle of the femur, and from the posterior
ligament of the knee-joint; and is inserted
into the inner two-thirds of the triangular
surface above the oblique line on the poste-
rior part of the shaft of the tibia, and into
the tendinous expansion covering the surface
of the muscle. The tendon of this muscle
is covered in by that of the Biceps and the
external lateral ligament of the knee-joint ;
it grooves the outer surface of the external
semilunar cartilage, and is invested by the
synovial membrane of the knee-joint.
Relations. By its superficial surface, with
the fascia above mentioned, which separates
it from the Gastrocnemius, Plantaris, popli-
teal vessels and internal popliteal nerve.
By its deep surface, with the tibio-flbular
articulation and back of the tibia.
The Flexor Longus Pollicis is situated
on the fibular side of the leg, and is the
most superficial, and largest of the three
next muscles. It arises from the lower two-
POSTERIOR TIBIO-FIBULAR REGION.
295
tliirds of the internal surface of the shaft of the fibula, with the exception of an
inch below, from the lower part of the interosseous membrane, from an inter-mus-
cular septum between it and the Peroneus longus and brevis, externally; and from
the fascia covering the Tibialis posticus. The fibres pass obliquely downwards
and backwards, and terminate around a tendon which occupies nearly the wliole
length of the posterior surface of the muscle. This tendon passes through a
groove on the posterior surface of the tibia, external to that for the Tibialis pos-
ticus and Flexor longus digitorum; it then passes through a second groove on the
posterior extremity of the astragalus, and along a third groove, beneath the tubercle
of the OS calcis, into the sole of the foot, where it runs forwards between the two
heads of the Flexor brevis pollicis, and is inserted into the base of the last pha-
lanx of the great toe. The grooves in the astragalus and os calcis which contain
the tendon of this muscle, are converted by tendinous fibres into distinct canals,
lined by synovial membrane; and as the tendon crosses the sole of the foot, it is
connected to the common Flexor by a tendinous slip.
Relations. By its superficial surface, with the Soleus and tendo Achillis, from
which it is separated by the deep fascia. By its deep surface, with the fibula.
Tibialis posticus, the peroneal vessels, the lower part of the interosseous mem-
brane, and the ankle-joint. By its outer border, with the Peroneus longus and
brevis. By its inner border, with the Tibialis posticus, and Flexor longus digi-
torum.
The Flexor Longus Digitorum is situated on the inner or tibial side of the leg.
At its origin, it is thin and pointed, but gradually increases in size as it descends.
It arises from the posterior surface of the shaft of the tibia, immediately be-
low the oblique line, to within three inches of its extremity, internal to the
tibial origin of the Tibialis posticus; some fibres also arise from the intermus-
cular septum, between it and the Tibialis posticus. The fibres terminate in a
tendon, which runs nearly the whole length of the posterior surface of the muscle.
This tendon passes, behind the inner Malleolus, in a groove, common to it, and the
Tibialis posticus, from which it is separated by a fibrous septum ; each tendon is
lined by a separate synovial membrane. It then passes, obliquely, forwards and
outwards, beneath the arch of the os calcis, into the sole of the foot, where,
crossing beneath the tendon of the Flexor longus pollicis, to which it is connected
by a strong tendinous slip, it becomes expanded, is joined by the Musculus
accessoriuri, and, finally divides into four tendons, which are inserted into the
bases of the last phalanges of the four lesser toes, each tendon passing through
a fissure in the tendon of the Flexor brevis digitorum, opposite the middle of the
first phalanges.
Relations. In the leg. By its superficial surface, with the Soleus, and the
posterior tibial vessels and nerve, from which it is separated by the deep fascia.
By its deep surface, with the Tibia and Tibialis posticus. In the foot, it is
covered by the Abductor pollicis, and Flexor brevis digitorum, and crosses beneath
the Flexor longus pollicis.
The Tibialis Posticus lies between the two preceding muscles, and is the most
deeply seated of all the muscles in the leg. It commences above, by two pointed
processes, separated by an angular inteiwal, through which, the anterior tibial
vessels pass forwards to the front of the leg, arising from the posterior surface
of the interosseous membrane, its whole length, excepting its lowest part, from
the posterior surface of the shaft of the tibia, external to the Flexor longus
digitorum, between the commencement of the oblique line above, and the centre
of the external border of the bone below, and from the upper two-thirds of the
inner surface of the shaft of the fibula; some fibres also arise from the deep
fascia, and from the intermuscular septa, separating it from the adjacent muscles
on each side. The fibres terminate in a tendon, which passes in front of the
Flexor longus digitorum, through a groove behind the inner Malleolus, enclosed
in a separate sheath; it then passes through another she.ith, over the internal
lateral ligament, and beneath the calcaneo-scaphoid articulation, and is inserted
296 MUSCLES AND FASCIA.
into the tuberosity of the scaphoid, and internal cuneiform bones. The tendon
of this muscle, contains a sesamoid bone, near its insertion, and gives off
fibrous expansions, one of which, passes backwards to the os calcis, others ovit-
wards to the middle and external cuneiform, and some forwards to the bases of
the third and fourth metatarsal bones.
Relations. By its superficial surface, with the Soleus, Flexor longus digito-
rum. Flexor longus pollicis, the posterior tibial vessels and nerve, and the
peroneal vessels, from which it is separated by the deep fascia. By its
deep surface, with the interrosseous ligament, the tibia, fibula, and ankle-
joint.
Nerves. The Popliteus is supplied by the internal popliteal nerve, the remain-
ing muscles of this group, by the posterior tibial nerve.
Actions. The Popliteus assists in flexing the leg upon the thigh, and, when
flexed, it may rotate the tibia inwards. The Tibialis posticus is a direct Extensor
of the tarsus upon the leg; acting in conjunction with the Tibialis anticus, it
turns the sole of the foot inwards, antagonizing the Peroneus longus which
turns it outwards. The Flexor longus digitorum, and Flexor longus pollicis, are
the direct Flexors of the phalanges, and, continuing their action, extend the foot
upon the leg ; they assist the Gastrocnemius and Soleus in extending the foot,
as in the act of walking, or in standing on tiptoe. In consequence of the oblique
direction of the tendon of the long Extensor, the toes would be drawn inwards,
were it not for the Flexor accessorius muscle, which is inserted into the outer side
of that tendon, and draws it to the middle line of foot, during its action. Taking
their fixed point from the foot, these muscles serve to maintain the upright pos-
ture, by steadying the tibia and fibula, perpendicularly, upon the ankle-joint. They
also serve to raise these bones from the oblique position they assume in the
stooping posture.
Fibular Region.
Pei'oneus Longus. Peroneus Brevis.
Dissection, These muscles are readily exposed, by removing the fascia, covering their
surface, from below upwards, in the line of direction of their fibres.
The Peroneus Longus is situated at the upper part of the outer side of the
leg. It arises from the head, and upper two-thirds of the outer surface of the
shaft of the fibula, from the deep fascia, and from the intermuscular septa,
between it and the muscles on the anterior, and those on the posterior surface
of the leg. It terminates in a long tendon, which passes behind the outer
malleolus, in a groove, common to it, and the Peroneus brevis, the groove being
converted into a canal by a fibrous band, and the tendons, invested by a com-
mon synovial membrane; it is then reflected, obliquely forwards, across the outer
side of the os calcis, being contained in a separate fibrous sheath, lined by a
prolongation of the synovial membrane, from the groove behind the malleolus.
Having reached the outer side of the cuboid bone, it runs, in a groove, on its
under surface, which is converted into a canal, by the long calcaneo-cuboid liga-
ment, lined by a synovial membrane, and crossing, obliquely, the sole of the foot,
is inserted into the outer side of the base of the metatarsal bone of the great toe.
The tendon of the muscle has a double reflection^ first, behind the external malleolus,
secondly, on the outer side of the cuboid bone; in both of these situations, the
tendon is thickened, and, in the latter, a sesamoid bone is usually developed in
its substance.
Relations. By its superficial surface, with the fascia and integument. By its
deep surface, with the fibula, the Peroneus brevis, os calcis, and cuboid bone.
By it§ anterior border, a tendinous septum intervenes between it and the
Extensor longus digitorum. By its posterior border, an intermuscular septum,
separates it from the Soleus above, and the Flexor longus pollicis below.
The Peroneus Brevis lies beneath the Peroneus longus, and is shorter and
FIBULAR REGION.
297
smaller than it. It arises from the lower two-thirds of the external surface of the
shaft of the fibula, internal to the Peroneus longus ; from the anterior and poste-
rior borders of the bone; and from the intei'muscular septa separating it from the
adjacent muscles on the front and back part of the leg. The fibres pass vertically
downwards, and terminate in a tendon, which runs through the same groove as
the preceding muscle, behind the external malleolus, being contained in the same
fibrous sheath, and lubricated by the same synovial membrane; it then passes
through a separate sheath on the outer side of the os calcis, above that for the
tendon of the Peroneus longus, and is finally inserted into the base of the meta-
tarsal bone of the little toe, on its dorsal surface.
Relations. By its superficial surface, with the Peroneus longus and the fascia
of the leg and foot. By its deep surface, with the fibula and outer side of the
OS calcis.
Nerves. The Peroneus longus and brevis are supplied by the musculo-cutaneous
branch of the external popliteal nerve.
Actions. The Peroneus longus and brevis extend the foot upon the leg, in con-
junction with the Tibialis posticus, antagonizing the Tibialis anticus and Peroneus
tertius, which are flexors of the foot. The Peroneus longus also everts the sole
of the foot; hence the extreme eversion observed in fracture of the lower end of
the fibula, where that bone offers no resistance to the action of this muscle.
Taking their fixed point below, they serve to steady the leg upon the foot. This
is especially the case in standing upon one leg, when the tendency of the superin-
cumbent weight is to throw the leg inwards; and the Peroneus longus overcomes
this by drawing on the outer side of the leg, and thus maintains the perpendicular
direction of the limb.
Surgical Anatomy. The student should now consider the position of the tendons of the
various muscles of the leg, their relation with the ankle-joint and surrounding blood-
vessels, and especially their action upon the foot, as their rigidity and contraction give rise
to one or the other forms of deformity known as cluh-foot. The most simple and common
deformity is the talipes equinus, the heel being raised from the ground by rigidity and con-
traction of the Gastrocnemius muscle, and the patient walking upon the ball of the foot.
In the talipes varus, which is the more common congenital form, the heel is raised by the
tendo Achillis, the inner border of the foot drawn upwards by the Tibialis anticus, ami the
anterior two-thirds of the foot twisted inwards by the Tibialis posticus and Flexor longus
digitorum, the patient walking upon the dorsum of the foot and outer ankle. In the talipes
vulgus the outer edge of the foot is raised by the Peronei muscles, and the patient walks
upon the inner ankle. In the talipes calcaneus the foot is raised by the Extensor muscles,
the heel is depressed, and the patient walks upon it. Each of these deformities may be
successfully relieved (after other remedies fail) by division of the opposing tendons; by this
means the foot regains its normal position, and the tendons heal by the organization of
lymph thrown out between the divided ends. The operation is easily performed by putting
the contracted tendon upon the stretch, and dividing it by means of a narrow sharp-
pointed knife inserted between it and the skin.
Muscles and Fascia of the Foot.
The fibrous bands which serve to bind down the tendons in front and behind the ankle
in their passage to the foot, should now be examined ; they are termed the annvlar liga-
ments, and are three in number, anterior, internal, and external.
The Anterior Annular Ligament consists of a superior or vertical portion,
which binds down the extensor tendons as they descend on the front of the tibia;
and an inferior or horizontal portion, which retains them in connection with the
tarsus: the two portions being connected by a thin intervening layer of fascia.
The upper and stronger portion is attached externally to the lower end of the
fibula, internally to the tibia, and above is continuous with the fascia of the leg :
it contains two separate sheaths, one internally, for the tendon of the Tibialis anti-
cus ;- one externally, for the tendons of the Extensor longus digitorum and Pero-
neus tertius, the tendon of the Extensor proprius pollicis, and the anterior tibial
vessels and nerve pass beneath it. The lower portion is attached externally to the
upper surface of the os calcis, in front of the depression for the intei-osseous ligament,
and internally to the inner malleolus and plantar fascia: it contains three sheaths;
the most internal for the tendon of the Tibialis anticus, the next in order for the
298 MUSCLES AND FASCIA.
tendon of tlie Extensor proprius polHcis, and the most external for tlie Extensor
communis digitorum and Peroneus tertius: the anterior tibial vessels and nerve lie
altogether beneath it. These sheaths are lined by separate synovial membranes.
The Internal Annular Ligament is a strong fibrous band, which extends from
the inner malleolus above, to the internal margin of the os calcis below, converting
a series of bony grooves in this situation into osteo-fibrous canals, for the passage
of the tendons of the Flexor muscles and vessels into the sole of the foot. It is
continuous above with the deep fascia of the leg, below with the plantar fascia
and the fibres of origin of the Abductor pollicis muscle. The three canals which
it forms, transmit from within outwards, first, the tendon of the Tibialis posticus;
second, the tendon of the Flexor longus digitorum , then the posterior tibial vessels
and nerve, which run through a broad space beneath the ligament; lastly, in a
canal formed partly by the astragalus, the tendon of the Flexor longus pollicis.
Each of these canals is lined by a separate synovial niembrane.
The External Annular Ligament extends from the extremity of the outer
malleolus to the outer surface of the os calcis, and serves to bind down the tendons
of the Peronei muscles in their passage beneath the outer ankle. The two tendons
are enclosed in one synovial sac.
Dissection of the Sole of the Foot. The foot should be placed on a high block with the
sole uppermost, and firmly secured in that position. Carry an incision around the heel
and along the inner and outer borders of the foot to the great and little toes. This incision
should divide the integument and thick layer of granular fat beneath, until the fascia is
visible ; it should then be removed from the fascia in a direction from behind forwards,
as seen in fig. 171.
The Plantar Fascia, the densest of all the fibrous membranes, consists of three
portions, a middle and two lateral.
The middle portion, of great strength and thickness, consists of dense glistening
fibres, disposed, for the most part, longitudinally; it is narrow and thick behind,
and attached to the inner tuberosity on the under surface of the os calcis, behind
the origin of the Flexor brevis digitorum, and becoming broader and thinner as it
passes forwards, divides opposite the middle of the metatarsal bones into five
fasciculi, one for each of the toes. Each of these fasciculi divides opposite the
metatarso-phalangeal articulation into two slips, which embrace the sides of the
fiexor tendons of the toes, and are inserted into the bases of the metatarsal bones,
and into the transverse ligaments of the corresponding articulation, thus forming
a series of arches through which the tendons of the short and long flexors pass
to the toes. The intervals left between the five primary fasciculi allow of the
passage of the digital vessels and nerves, and the tendons of the Lumbricales
and Interossei muscles. At the point of division of the fascia into fasciculi and
slips, numerous transverse fibres are superadded, which serve to increase the
strength of the fascia at this part, by binding the processes together and con-
necting them with the integument. The middle portion of the plantar fascia is
continuous with the lateral portions at each side, and sends upwards into the foot,
at their point of junction, two strong vertical intermuscular septa, broader in front
than behind, which separate the middle from the external and internal plantar
group of muscles. From these again thinner transverse septa are derived, which
separate the various layers of muscles in this region; the upper surface of this
fascia gives attachment behind to the Flexor brevis digitorum muscle.
The lateral portions of the plantar fascia cover the sides of the foot.
The outer portion covers the under surface of the Abductor minimi digiti ; it
is very thick behind, thin in front, and extends from the os calcis forwards to the
base of the fifth metatarsal bone, into the outer side of which it is inserted; it
is continuous internally with the middle portion of the plantar fascia, and exter-
nally with the dorsal fascia.
The inner portion is very thin, and covers the Abductor pollicis muscle ; it is
attached behind to the internal annular ligament, is continuous around the side
of the foot with the dorsal fascia, and externally with the middle portion of the
plantar fascia.
OF THE FOOT. 299
Muscles of the Foot.
These are divided into two groups: i. Those on the doi^suin; 2. Those on the
plantar surface.
1. Dorsal Region.
Extensor Brevis Digitorum.
The Fascia on the dorsum of the foot is a thin membranous layer, continuous
above w^ith the anterior margin of the annular ligament; it becomes gradually lost
in front, opposite the heads of the metatarsal bones, and on each side blends w^ith
the lateral portions of the plantar fascia: it forms a sheath for the tendons placed
on the dorsum of the foot. On the removal of this fascia, the muscles of the
dorsal region of the foot are exposed, covered by their investing fascia.
The Extensor Brevis Digitorum is a thin and somew^hat broad muscle, which
arises by a rounded extremity from the outer side of the os calcis, in front of the
groove for the Peroneus brevis, from the astragalo-calcanean ligament, and from
the anterior annular ligament of the tarsus: passing obliquely across the dorsum
of the foot, it terminates in four tendons. The innermost, which is the largest, is
inserted into the first phalanx of the great toe; the other three into the outer
sides of the long extensor tendons of the second, third, and fourth toes.
Relations. By its superficial surface, with the fascia of the foot, the tendons
of the Extensor longus digitorum, and Extensor proprius pollicis. By its deep
surface, with the tarsal and metatarsal bones, and the Dorsal interossei muscles.
Nerves. It is supplied by the anterior tibial nerve.
Actions. The Extensor brevis digitorum is an accessory to the long Extensor,
extending the phalanges of the four inner toes, but acting only on the first
phalanx of the great toe. The obliquity of its direction counteracts the oblique
movement given to the toes by the long Extensor, so that both muscles acting
together, the toes are evenly extended.
2. Plantar Region.
The muscles in the plantar region of the foot may be divided into three groups,
in a similar manner to those in the hand. Those of the internal plantar region,
are connected with the great toe, and correspond with those of the thumb; those
of the external plantar region, are connected with the little toe, and correspond
with those of the little finger; and those of the middle plantar region, are con-
nected with the tendons intervening between the two former groups. The Inter-
ossei are considered separately.
Internal Plantar Group. External Plantar Group.
Abductor Pollicis. Abductor Minimi Digiti.
Flexor Bi'evis Pollicis. Flexor Brevis Minimi Digiti.
Adductor Pollicis.
Transversus Pedis.
Middle Plantar Group.
Flexor Brevis Digitorum. Musculus Accessorius.
Lumbricales.
In order to facilitate their dissection, it will be found more convenient to divide
them into three layers, as they present themselves, in the order in which they are
successively exposed.
First Layer.
Abductor Pollicis. Flexor Brevis Digitorum.
Abductor Minimi Digiti.
Dissection. Remove the fascia on the inner and outer sides of the foot, commencing in
front over the tendons, and proceeding backwards. The central portion should be divided
transversely in the middle of the foot, and the two flaps dissected forwards and l)ackwards.
300
MUSCLES AND FASCIA.
The Abductor Pollicis lies along the inner border of the foot. It arises from
the inner tuberosity of the os calcis, from the internal annular ligament, from the
plantar fascia, and from the intermuscular septum between it and the Flexor
brevis digitorum. The fibres terminate in a tendon, which is inserted, together
with the innermost tendon of the Flexor brevis pollicis, into the internal sesamoid
bone and inner border of the base of the first phalanx of the great toe.
Helations. By its superficial surface, with the internal plantar fascia. By its
r -Mt ^ l!^^ CI 1 /.XT- -n j^ dceip surfacc, with the Flexor brevis
176. — Muscles of the Sole of the Foot. ^ '' '
First Layei'.
pollicis, the Musculus accessorius, and
the tendons of the Flexor longus digi-
torum and Flexor longus pollicis, the
Tibialis anticus and posticus, the plan-
tar vessels and nerves, and the articu-
lations of the tarsus.
The Flexor Brevis Digitorum lies
in the middle line of the sole of the
foot immediately beneath the plantar
fascia, with which it is firmly united.
It arises, by a narrow tendinous pro-
cess, from the inner tuberosity of the
OS calcis, from the central part of the
plantar fascia, and from the intermus-
cular septa between it and the adja-
cent muscles. It passes forwards and
divides into four tendons. Opposite
the middle of the first phalanges, each
tendon' presents a longitudinal slit, to
allow of the passage of the correspond-
ing tendon of the Flexor longus digito-
rum, the two portions forming a groove
for its reception, and after reuniting,
divides a second time into two pro-
cesses, which are inserted into the
sides of the second phalanges. The
mode of division of the tendons of the
Flexor brevis digitorum, and their in-
sertion into the phalanges, is analogous
to the Flexor sublimis in the hand.
Relations. By its superficial sur-
face, with the plantar fascia. By its
deep surface, with the Musculus acces-
sorius, the Lumbricales, the tendons of
the Flexor longus digitorum, and the
plantar vessels and nerves, from which
it is separated by a thin layer of
fascia. The outer and inner borders
are separated from the adjacent mus-
cles by means of vertical prolongations
of the plantar fascia.
The Abductor 3Iinimi Digiti lies along the outer border of the foot. It arises,
by a very broad origin, from the outer tuberosity of the os calcis, from the under
surface of the os calcis in front of both tubercles, from the outer portion of the
plantar fascia, and the intermuscular septum between it and the Flexor brevis
digitorum. Its tendon, after gliding over a smooth facet on the under surface of
the base of the fifth metacarpal bone, is inserted into the outer side of the base of
the first phalanx of the little toe.
Relations. By its superficial surface, with the outer portion of the plantar
OF THE SOLE OF THE FOOT.
301
177. — Muscles of tlie Sole of the Foot.
Second Layer.
fascia. By its deep surface, with the outei' head of the Musculus accessorius, the
Flexor brevis minimi digiti, the long plantar ligament, and Peroneus longus. Its
inner side is separated from the Flexor brevis digitorum by a vertical septum of
fascia.
Dissection. The muscles of the supei'ficial layer should be divided at their origin, by in-
serting the knife beneath each, and cutting obliquely backwards, so as to detach them from
the bone ; they should then be drawn forwards, in order to expose the second layer, but not
separated from their insertion. The two
layers are separated by a thin membrane,
the deep plantar fascia, on the removal of
which is seen the tendon of the Flexor
longus digitorum, with its accessory muscle,
the Flexor longus poUicis and the Lum-
bricales. The long flexor tendons cross
each other at an acute angle, the Flexor
longus pollicis running along the inner
side of the foot, on a plane superior to
that of the Flexor longus digitorum, the
direction of which is obliquely outwards.
Second Layer.
Flexor Accessorius.
Lumbricales.
The Flexor Accessorius arises pos-
teriorly by tw^o heads, the inner or
larger, which is muscular, being at-
tached to the inner concave surface of
the OS calcis and to the calcaneo-
scaphoid ligament; the outer head,
flat and tendinous, to the under sur-
face of the OS calcis, in front of its
outer tuberosity, and to the long
plantar ligament: the two portions
become united at an acute angle, and
are inserted into the outer margin
and upper and under surfaces of the
tendon of the Flexor longus digitorum,
forming a kind of groove, in which
the tendon is lodged. A few fibres
from the upper surface of the muscle
blend with a tendinous expansion from
the Flexor longus pollicis.
Relations. By its superficial sur-
face, with the muscles of the super-
ficial layer, from which it is separated
by the external plantar vessels and
nerves. By its deep surface, with the
OS calcis and long calcaneo- cuboid
ligament.
The Lumbricales are four small
muscles, accessory to the tendons of
the Flexor longus digitorum: they arise from the tendons of the long Flexor, as
far back as their angle of division, each arising from two tendons, except the
internal one. Each muscle terminates in a tendon, which passes forwards on
the inner side of each of the lesser toes, and is inserted into the expansion of
the long Extensor and base of the second phalanx of the corresponding toe.
Dissection. The flexor tendons should be divided at the back part of the foot, and the
Musculus accessorius at its origin, and drawn forwards, in order to expose the third
layer.
302
MUSCLES AND FASCIA.
Flexor Brevis Pollicis.
Adductor Pollicis.
Third Layer.
Flexor Brevis Minimi Digiti.
Transversus Pedis.
The Flexor Brevis Pollicis arises bj a pointed tendinous process, from the
inner border of the cuboid bone, from the contiguous portion of the external
cuneiform, and from the prolongation of the tendon of the Tibialis posticus, which
is attached to that bone. The muscle
178.— Muscles of the Sole of the Foot.
Third Layer.
divides, in front, into two portions,
which are inserted into the inner and
outer sides of the base of the first
phalanx of the great toe, a sesamoid
bone being developed in each tendon
at its insertion. The inner head of
this muscle is blended with the Ab-
ductor pollicis previous to its insertion ;
the outer head, with the Adductor pol-
licis; and the tendon of the Flexor
longus pollicis lies in a groove between
them.
Relations. By its superficial sur-
face, with the Abductor pollicis, the
tendon of the Flexor longus pollicis
and plantar fascia. By its deep sur-
face, with the tendon of the Peroneus
longus,r and metatarsal bone of the
great toe. By its inner border, with
the Abductor pollicis. By its outer
border, with the Adductor pollicis.
The Adductor Pollicis is a large,
thick, fleshy mass, passing obliquely
across the foot, and occupying the hol-
low space between the four outer meta-
tarsal bones. It arises from the tarsal
extremities of the second, third, and
fourth metatarsal bones, and from the
sheath of the tendon of the Peroneus
longus; and is inserted, together with
the outer head of the Flexor brevis
pollicis, into the outer side of the base
of the first phalanx of the great toe.
The Flexor Brevis Minimi Digiti is
situated along the outer border of the
metatarsal bone of the little toe. It
arises from the base of the metatarsal
bone of the little toe, and from the
sheath of the Peroneus longus; its
tendon is inserted into the base of the
first phalanx of the little toe, on its outer side.
Relations. By its superficial surface, with the plantar fascia and tendon of the
Abductor minimi digiti. By its deep surface, with the fifth metatarsal bone.
The Transversus Pedis is a narrow, flat, muscular fasciculus, stretched trans-
versely across the heads of the metatarsal bones, between them and the flexor
tendons. It arises from the under surface of the head of the fifth metatarsal
bone, and from the transverse ligament of the metatarsus; and is inserted into the
outer side of the first phalanx of the great toe; its fibres being blended with the
tendon of insertion of the Adductor pollicis.
OF THE SOLE OF THE FOOT.
303
Relations. By its under surface, with tlie tendons of the long and short
Flexors and Lumbricales. By its upper surface, with the Interossei.
The Interossei.
The Interossei muscles in the foot are similar
to those in the hand. They are seven in number,
and consist of two groups, dorsal, and plantar.
The Dorsal Interossei, four in number, are
situated between the metatarsal bones. They are
bipenniform muscles, arising by two heads from
the adjacent sides of the metatarsal bones between
which they are placed, their tendons being inserted
into the bases of the first phalanges, and into the
aponeurosis formed by the common extensor tendon.
In the angular interval left between each muscle
at its posterior extremity, the perforating arteries
pass to the dorsum of the foot; except in the first
Interosseous muscle, where the interval allows the
passage of the communicating branch of the dor-
salis pedis artery. The first Dorsal interosseous
muscle is inserted into the inner side of the second
toe; the other three are inserted into the outer
sides of the second, third, and fourth toes. They
are all abductors from an imaginary line or axis
drawn through the second toe.
The Plantar Interossei, three in number, lie
beneath, rather than between, the metatarsal bones.
They are single muscles, and are each connected
with but one metatarsal bone. They arise from the
base and inner sides of the shaft of the third, fourth,
and fifth metatarsal bones, and are inserted into the
inner sides of the bases of the first phalanges of
the same toes, and into the aponeurosis of the
common extensor tendon. These muscles are all
adductors, towards an imaginary line, extending
through the second toe.
Nerves. The internal plantar nerve supplies
the Abductor pollicis, Flexor brevis digitorum.
Flexor brevis pollicis, and the first and second
Lumbricales. The external plantar nerve supplies
the Abductor minimi digiti, Musculus accessorius,
third and fourth Lumbricales, Adductor pollicis.
Flexor brevis minimi digiti, Transversus pedis, and
all the Interossei.
SURGICAL ANATOMY.
The student should now consider the effects
produced by the action of the various muscles,
in fractures of the bones of the lower extre-
mity. The more common forms of fracture have
been especially selected for illustration and de-
scription.
179.
-The Dorsal Interossei.
Left Foot.
180. — The Plantar Interossei.
Left Foot.
304
SURGICAL ANATOMY,
-Fracture of the Neck of the Femur within the
Capsular Ligament.
ELLUS SUPCRtan
URATOR INTERNUS
ELLUS INFERIOR
TURATOR EXTERNUI
XBRATUS FCMORIS
182. — Fracture of the Femur
below the Ti'ochanter Minor.
SEMI-TENDIMr:
Fracture of the neck oj
the femur internal to the
capsular ligament (fig. 181)
is a very common accident,
and is most frequently-
caused by indirect violence,
such as slipping off the edge
of the kerbstone, the im-
petus and weight of the
body falling upon the neck
of the bone. It usually
occurs in females, and sel-
dom under fifty years of
age. At this period of
life, the neck of the bone,
under certain conditions of
the system, assumes a ho-
rizontal instead of an ob-
lique direction, the head
being on a level with the
trochanter major; the can-
cellous tissue of the neck
becomes soft and infiltrated
with fatty matter, the com-
pact tissue is partially
absorbed, and the amount of earthy matter becomes
greater in proportion to the ardmal constituent;
hence, the bones are brittle, and more liable to
fracture. The characteristic marks of this accident
are slight shortening of the limb, and eversion of the
foot, neither of which symptoms occur, however, in
some cases until a short time after the injury. The
eversion is caused by the combined action of the
external rotator muscles, as well as by the Psoas and
Iliacus, Pectineus, Adductors, and Glutei muscles.
The shortening and retraction of the limb is pro-
duced by the action of the Glutei, and by the Rectus
femoris in front, and the Biceps, Semi-tendinosus,
and Semi-membranosus behind.
Fracture of th.Q femur below the trochanter minor
(fig. 182), is an accident of not unfrequent occurrence,
and is attended with great displacement producing
considerable deformity. The upper fragment, the
portion chiefly displaced, is tilted forwards almost at
right angles with the pelvis by the combined action
of the Psoas and Iliacus, and at the same time everted
and drawn outwards by the external rotator and
Glutei muscles, causing a marked prominence at the
upper and outer side of the thigh, and much pain
from the bruising and laceration of the muscles.
The limb is shortened, from the lower frag-
ment being drawn upwards by the Rectus in front,
and the Biceps, Semi-membranosus, and Semi-tendi-
nosus behind ; and at the same everted, and the upper
end thrown outwards, the lower inwards, by the
Pectineus and Adductor muscles. This fracture may
OF THE MUSCLES OF THE LOWER EXTREMITY
305
— Fracture of the Femur
above the Condyles.
be reduced in two different methods: either by direct relaxation of all the opposing
muscles, to effect which the limb should be placed on a double inclined plane;
or by overcoming the contraction of the muscles by continued extension, which may
be effected by means of the long splint.
Oblique fracture of the femur immediately above
the condyles (^g.lS^), '^s a formidable injury, and
attended with considerable displacement. On examin-
ation of the limb, the lower fragment may be felt
deep in the popliteal space, being drawn backwards
by the Gastrocnemius, Soleus, and Plantaris muscles,
and upwards by the Posterior femoral, and Rectus
muscles. The pointed end of the upper fragment is
drawn inwards by the Pectineus and Adductor muscles,
and tilted forwards by the Psoas and Iliacus, piercing
the Rectus muscle, and occasionally the integument.
Relaxation of these muscles, and direct approxima-
tion of the broken fragments, is effected by placing
the limb on a double inclined plane. The greatest
care is requisite in keeping the pointed extremity of
the upper fragment in proper apposition; otherwise,
after union of the fracture, extension of the limb is
partially destroyed from the Rectus muscle being held
down by the fractured end of the bone, and from the
patella when elevated being drawn upwards against
it.
Fracture of the joafeZ/a (fig. 184), may be produced by muscular action, or by
direct violence. When produced by muscular action, it occurs thus: a person
in danger of falling forwards, attempts to recover
himself by throwing the body backwards, and the
violent action of the Quadriceps extensor upon the
patella snaps that bone transversely across. The
upper fragment is drawn up the thigh by the Quadri-
ceps extensor, the lower fragment being retained in
its position by the ligamentum patellae ; the extent of
separation of the two fragments depending upon the
degree of laceration of the ligamentous structures
around the bone. The patient is totally unable to
straighten the limb ; the prominence of the patella is
lost; and a marked but varying interval can be felt
between the fragments. The treatment consists in
relaxing the opposing muscles, which may be effected
by raising the trunk, and slightly elevating the limb,
which should be kept in a straight position. Union is
usually ligamentous. Li fracture from direct violence,
the bone is generally comminuted, or fractured obliquely
or perpendicularly.
Oblique fracture of the shaft of the tibia (fig. 185), usually occurs at the lower
fourth of the bone, this being the narrowest and weakest part, and is generally ac-
companied with fracture of the fibula. If the fracture has taken place obliquely
from above, downwards, and forwards, the fragments ride over one another, the
lower fragment being drawn backwards and upwards by the powerful action
of the muscles of the calf; the pointed extremity of the upper fragment pro-
jects' forwards immediately beneath the integument, often protruding through
it, and rendering the fracture a compound one. If the direction of the fracture
is the reverse of that shewn in the figure, the pointed extremity of the lower
fragment projects forwards, riding upon the lower end of the upper one. By
relaxing the opposing muscles (bending the knee), with extension made from
184. — Fracture of the Patella.
3o6
SURGICAL ANATOMY,
the knee and ankle, the fragments may
be brought into apposition. It is often
necessary, however, in compound fracture,
to remove a portion of the projecting bone
with the saw before complete adaptation can
be effected.
Fracture of the Jibula, with dislocation
of the tibia inwards (fig. 1 86), commonly
known as ' Pott's Fracture,' is one of the
most frequent injuries of the ankle-joint.
The end of the tibia rests upon the inner
side of the Astragalus, the internal lateral
ligament of the ankle-joint is ruptured, and
the inner malleolus projects inwards beneath
the integument which is tightly stretched
over it, and in danger of bursting. The
fibula is broken, usually about three inches
above the ankle, and occasionally that por-
tion of the tibia with which it is more directly
connected below; the foot is everted by the
action of the Peroneus longus, its inner
border resting upon the ground, and, at the
same time, the heel is drawn up by the
muscles of the calf. This injury may be at
once reduced by flexing the leg at right
angles with the thigh, which relaxes all the
opposing muscles, and by making slight ex-
tension from the knee and ankle.
! 5. — Oblique Fracture of the Shaft
of the Tibia.
186. — Fracture of the Fibula, with Dislocation of the Tibia inwards.
' Pott's Fracture.'
Of the Arteries.
THE Arteries are cylindrical tubular vessels, which serve to convey blood from
the heart to every part of the body. These vessels were named arteries
{ar]p rrjpebv, to contain air), from the belief entertained by the ancients that they
contained air. To Galen is due the honour of refuting this opinion; he showed
that these vessels, though for the most part empty after death, contained blood
in the living body.
The pulmonary artery, which arises from the right ventricle of the heart, carries
venous blood directly into the lungs, from whence it is returned by the pulmonary
veins into the left auricle. This constitutes the lesser or pulmonic circulation.
The great artery which arises from the left ventricle, the aorta, conveys arterial
blood to the body generally; from whence it is brought back to the right side of the
heart by means of the veins. This constitutes the greater or systemic circulation.
The distribution of the systemic arteries is like a highly ramified tree, the
common trunk of which, formed by the aorta, commences at the left ventricle of
the heart, the smallest ramifications corresponding to the circumference of the
body and the contained organs. The arteries are found in nearly every part of
the animal body, with the exception of the hairs, nails, and epidermis; and the
larger trunks usually occupy the most protected situations, running, in the limbs,
along the flexor side, where they are less exposed to injury.
There is considerable variation in the mode of division of the arteries; occa-
sionally a short trunk subdivides into several branches at the same point, as we
observe in the cceliac and thyroid axes; or the vessel may give off several branches
in succession, and still continue as the main trunk, as is seen in the arteries of the
limbs ; but the usual division is dichotomous, as, for instance, the aorta dividing into
the two common iliacs; and the common carotid, into the external and internal.
The branches of arteries arise at very variable angles; some, as the superior
intercostal, arise from the aorta at an obtuse angle; others, as the lumbar arteries,
at a right angle; or, as the spermatic, at an acute angle. An artery from which a
branch is given off is smaller in size than the trunk from which it arises, but retains
a uniform diameter until a second branch is derived from it ; but if an artery
divides into two branches, the combined area of the two vessels is, in nearly every
instance, somewhat greater than that of the trunk ; and the combined area of all
the arterial branches greatly exceeds the diameter of the aorta; so that the arteries
collectively may be regarded as a cone, the apex of which corresj)onds to the aorta;
the base, to the capillary system.
The arteries, in their distribution, communicate freely with one another, forming
what is called an anastomosis (ava, between; arofjia, mouth), or inosculation, and
this communication is very free between the large, as well as between the smaller
branches. The anastomoses between trunks of equal size is found where great
freedom and activity of the circulation is requisite, as in the brain; here the two
vertebral arteries unite to form the basilar, and the two internal carotid arteries
are connected by a short inter-communicating trunk; it is also found in the ab-
domen, the intestinal arteries having very free anastomoses between their larger
branches. In the limbs, the anastomoses are most frequent and of largest size
around the joints; the branches of an artery above, freely inosculating with
branches from the vessel below; these anastomoses are of considerable interest to
the surgeon, as it is by their enlargement that a collateral circulation is established
after the application of a ligature to an artery for the cure of aneurism. The
smaller branches of arteries anastomose more frequently than the larger, and
between the smallest twigs these inosculations become so numerous as to consti-
tute a close network that pervades nearly every tissue of the body.
Throughout the body generally the larger arterial branches pursue a perfectly
straight course, but in certain situations they are tortuous; thus the facial artery
3o8 ARTERIES.
in its coui'se over the face, and the labial arteries of the lips, are extremely tor-
tuous in their course, to accommodate themselves to the movements of these parts.
The uterine arteries are also tortuous, to accommodate themselves to the increase of
size which this organ undergoes during pregnancy. Again, the internal carotid
and vertebral arteries, previous to their entering the cavity of the skull, describe
a series of curves, which are evidently intended to diminish the velocity of the
current of blood, by increasing the extent of surface over which it moves, and
adding to the amount of impediment which is produced from friction.
The smaller arterial branches terminate in a system of minute anastomosing
vessels which pervade every tissue of the body. These vessels, from their minute
size, are termed capillaries (capillus, a hair). They are interposed between the
smallest branches of the arteries and the commencing veins, constituting a net-
work, the branches of which are of nearly uniform size, their average diameter
being about the -joVo^ ^^ ^^ inch; but the size of the smaller capillaries, and the
diameter of the meshes between them, vary in the different organs.
The arteries are dense in structure, of considerable strength, highly elastic,
and, when divided, they preserve, although empty, their cylindrical form.
They are composed of three coats, internal, middle, and external.
The internal is an epithelial and elastic coat; it consists of two layers, the
innermost of which is composed of a single layer of elliptical or spindle-shaped
epithelial particles, with round or oval nuclei, resting upon a striated and perfo-
rated transparent colourless membrane, highly elastic, but extremely thin and
brittle, disposed in one or more layers, and forming the chief substance of the
inner coat.
The middle, or contractile coat, consists of muscular and elastic fibres, it is of
a reddish yellow colour, highly elastic, and consists of numerous layers of non-
striated muscular fibres, disposed in a circular forfia around the vessel, having inter-
mixed with them layers of fine elastic or fenestrated membrane; as many as forty
layers have been counted in the aorta, twenty-eight in the carotid, and fifteen in
the subclavian artery. The muscular tissue exists in greatest abundance in the
smallest arteries, whilst in the larger trunks it is blended with much elastic tissue;
the great thickness of the walls of the arteries is due chiefly to this coat.
The external, or areolar and elastic coat, consists of condensed areolar and
elastic tissue; in the larger arteries it is composed of two distinct layers; an inner,
composed of elastic tissue, most distinct in the larger arteries; and an external
layer of condensed areolo-fibrous tissue, the constituent fibres being disposed more
or less diagonally or obliquely around the vessel. In the smaller arteries the
elastic tissue is wanting, the areolar coat increasing in proportion.
Some arteries have extremely thin coats in proportion to their size; this is
especially the case in those situated in the cavity of the cranium and spinal canal
the difference depending upon the greater thinness of the external and middle
coats.
The arteries in their distribution throughout the body, are included m a thin
areolo-fibrous investment, which forms what is called their sheath. In the limbs,
this is usually formed by a prolongation of the deep fascia; in the upper part of
the thigh it consists of a continuation downwards of the transversalis and iliac
fasciae of the abdomen ; in the neck, of a prolongation of the deep cervical fascia.
The included vessel is loosely connected with its sheath by a delicate areolar
tissue; and the sheath usually encloses the accompanying veins and sometimes a
nerve. Some arteries, as those in the cranium, are not included in sheaths.
Arteries are supplied with blood-vessels like the other organs of the body, they
are called vasa vasorum. These nutrient vessels arise from a branch of the artery
or from a neighbouring vessel, at some considerable distance from the point at
which they are distributed; they ramify in the loose areolar tissue connecting the
artery with its sheath, and are distributed to the extei-nal and middle coats, and
according to Arnold and others, supply the internal coat. Minute veins serve to
return the blood from these vessels, they empty themselves into the ven« comites
in connection with the artery. Arteries are also provided with nerves; they are
GENERAL ANATOMY.
309
derived chiefly from the sympathetic, but partly from the cerebro-spinal system.
They form intricate plexuses upon the surface of the larger trunks, the smaller
branches being usually accompanied by single filaments; their exact mode of dis-
tribution is unknown.
In the description of the arteries, we shall first consider the efferent trunk of
the systemic circulation, the aorta, and its branches; and then the efferent trunk
of the pulmonic circulation, the pulmonary artery.
The Aorta.
The aorta {aoprrj; arteria magna) is the main trunk of a series of vessels,
which, arising from the heart, conveys the red oxygenated blood to every part of
the body for its nutrition. This vessel commences at the upper part of the left
187. — The Arch of the Aorta and its Branches.
Sf Vac/Its
BeeiiTrent laryngeal
leftVayus
I c . 1 8 8 Flan of tluBraTiehiS
%ifl Cormmrg
ventricle, and after ascending for a short distance, arches backwards to the left
side, over the root of the left lung, descends within the thorax on the left side of
the vertebral column, passes through the aortic opening in the Diaphragm, and
entering the abdominal cavity, terminates, considerably diminished in size, oppo-
site the fourth lumbar vertebra, where it divides into the right and left common
310 ARTERIES.
iliac arteries. Hence its subdivision into the arch of the aorta, the tlioracic aorta
and the abdominal aorta, from the direction or position peculiar to each part.
Akch of the Aorta.
Dissection. In order to examiue the arch of the aorta, the thorax should be opened, by
dividing the cartilages of the ribs on each side of the sternum, and raising this bone from
below upwards, and then sawing through the sternum on a level with its articulation with
the clavicle. By this means the relations of the large vessels to the upper border of the
sternum and root of the neck are kept in view.
The arch of the aorta extends from the origin of the vessel at the upper part
of the left ventricle, to the lower border of the body of the third dorsal vertebra.
At its commencement, it ascends behind the sternum, obliquely upwards and
forwards towards the right side, and opposite the upper border of the second
costal cartilage of the right side, passes transversely from right to left, and from
before backwards to the left side of the second dorsal vertebra; it then descends
upon the left side of the body of the third dorsal vertebra, at the lower border of
which it becomes the thoracic aorta. Hence this portion of the vessel is divided
into an ascending, a transverse, and a descending portion. The artery in its
course describes a curve, the convexity of which is directed upwards and to the
right side, the concavity in the opposite direction.
Ascending Part of the Arch.
The ascending portion of the arch of the aorta is about two inches in length.
It commences at the upper part of the left ventricle, in front of the left auriculo-
ventricular orifice, and opposite the middle of the sternum on a line with its junc-
tion to the third costal cartilage; it passes obliquely ujjwards in the direction of
the heart's axis, to the right side, as high as the upper border of the second costal
cartilage, describing a slight curve in its course, and being situated, when dis-
tended, about a quarter of an inch behind the posterior surface of the sternum.
A little above its commencement, it is somewhat enlarged, and presents three small
dilatations, called the sinuses of the aorta (sinuses of Valsalva) opposite to which
are attached the three semi-lunar valves, which serve the purpose of preventing
any regurgitation of blood into the cavity of the ventricle. A section of the
aorta opposite this part has a somewhat triangular figure; but below the attach-
ment of the valves it is circular. This portion of the arch is contained in the
cavity of the pericardium, and together with the pulmonary artery, is invested in
a tube of serous membrane, continued on to them from the surface of the heart.
Relations. The ascending part of the arch is covered at its commencement by
the trunk of the pulmonary artery and the right auricular appendage, and, higher
up, is separated from the sternum by the pericardium, some loose areolar tissue,
and the remains of the thymus gland; behind, it rests upon the right pulmonaiy
vessels and root of the right lung. On the right side, it is in relation with the
superior vena cava and right auricle; on the left side, with the pulmonary artery.
/ Plan of the Relations of the Ascending Part of the Arch.
In front.
Pulmonary artery.
Eight auricular appendage.
Pericardium.
Remains of thymus gland.
Right side. f Arch of \ Xe/it side.
Superior cava. [ ^ Aorta. ^ j Pulmonary artery.
Right auricle.
Behind.
Right pulmonary vessels.
Root of right lung.
ARCH OF AORTA.
Transverse Part of the Arch.
3"
The second or transverse portion of the arch commences at the upper border of
the second costo-sternal articulation of the right side in front, and passes from
right to left, and from before backwards, to the left side of the second dorsal
vertebra behind. Its upper border is usually about an inch below the upper
margin of the sternum.
Relations. Its anterior surface is covered by the left pleura and lung, and
crossed towards the left side by the left pneumogastric and phrenic nerves, and
cardiac branches of the sympathetic. Its posterior surface lies on the trachea
just above its bifurcation, the great cardiac plexus, the oesophagus, thoracic duct,
and left recurrent laryngeal nerve. Its superior border is in relation with the
left innominate vein; and from its upper part are given off the innominate, left
carotid, and left subclavian arteries. By its lower border, with the bifurcation of
the pulmonary artery, and the remains of the ductus arteriosus, which is con-
nected with the left division of that vessel; the left recurrent laryngeal nerve
winds round it, whilst the left bronchus passes below it.
Plan of the Relations op the Transverse Part of the Arch.
Above.
Left innominate vein.
Arteria innominata.
Left carotid.
Left subclavian.
In front. /'^^~^^\ Behind.
Left pleura and lung. X Arch of \ Trachea.
Left pneumogastric nerve. / Aorta. \ Cardiac plexus.
Left phrenic nerve. 1 Transverse ) CEsophagus.
Cardiac nerves. \ Portion. / Thoracic duct.
Left recurrent nerve.
Below.
Bifurcation of pulmonary artery.
Eemains of ductus arteriosus.
Left recurrent nerve.
Left bronchus.
Descending Part of the Arch.
The descending portion of the arch has a straight direction, inclining down-
wards on the left side of the body of the third dorsal vertebra, at the lower
border of which it becomes the thoracic aorta.
Relations. Its anterior surface is covered by the pleura and root of the left
lung ; behind, it lies on the left side of the body of the third dorsal vertebra. On
its right side lies the oesophagus and thoracic duct; on its left side it is covered
by the pleura.
Plan of the Relations of the Descending Part of the Arch.
In front.
Pleura.
Eoot of left lung.
Right side. f Arch of \ Left side.
CEsophagus. [ Aorta. | Pleura.
Thoracic duct. \ Descending j
Portion.
Behind.
Left side of body of third dorsal vertebra.
The ascending, transverse, and descending portions of the arch vary in position
according to the movements of respii-ation, being lowered, together with the
312 ARTERIES.
trachea, bronchi, and pulmonary vessels, during inspiration by the descent of the
diaphragm, and elevated during expiration, when the diaphragm ascends. These
movements are greater in the ascending than the transverse, and in the latter
than the descending part.
Peculiarities. The height to which the aorta rises in the chest is usually about an inch
below the upper border of the sternum ; but it may ascend nearly to the top of that bone.
Occasionally it is found an inch and a half; more rarely, three inches below this point.
Direction. Sometimes the aorta arches over the root of the right instead of the left lung,
as in birds, and passes down on the right side of the spine. In such cases, all the viscera
of the thoracic and abdominal cavities are transposed. Less frequently, the aorta, after
arching over the right lung, is afterwards directed to its usual position on the left side of
the spine, this peculiarity not being accompanied by any transposition of the viscera.
Conformation. The aorta occasionally divides into an ascending and a descending trunk,
as in some quadrupeds, the former being directly vertically upwards, and subdividing into
three branches, to supply the head and upper extremities. Sometimes the aorta subdivides
soon after its origin into two branches, which soon reunite. In one of these cases, the
oesophagus and trachea were found to pass through the interval left by their division ;
this is the normal condition of the vessel in the reptilia.
Surgical Anatomy. Of all the vessels of the arterial system, the aorta, and more espe-
cially its arch, is most frequently the seat of disease ; hence it is important to consider
some of the consequences that may ensue from aneurism of this part.
It will be remembered, that the ascending part of the arch is contained in the pericar-
dium, just beliind the sternum, its commencement being crossed by the pulmonary artery
and right auricular appendage, having the root of the right lung behind, the vena cava on
the right side, and the pulmonary artery and left auricle on the left side.
Aneurism of the ascending aorta, in the situation of the aortic sinuses, in the great
majority of cases, affects the right coronary sinus ; this is mainly owing to the regurgi-
tation of blood upon the sinuses, taking place chiefly on the right anterior aspect of the
vessel. As the aneurismal sac enlarges, it may compress any or all of the structures in
immediate proximity with it, but chiefly projects towards the right anterior side ; and,
consequently, interferes mainly with those structures that have a corresponding relation
with the vessel. In the majority of cases, it bursts in the cavity of the pericardium, the
patient suddenly drops down dead, and, upon a post-mortem examination, the pericardial
bag is found full of blood : or it may compress the right auricle, or the pulmonary artery,
and adjoining part of the right ventricle, and open into one or the other of these parts, or
it may compress the superior cava.
Aneurism of the ascending aorta, originating above the sinuses, most frequently impli-
cates the right anterior wall of the vessel ; this is probably mainly owing to the blood
being impelled against this part. Its direction is also chiefly towards the right of the
median line. If it attains a large size and projects forwards, it may absorb the sternum
and the cartilages of the ribs, usually on the right side, and appear as a pulsating tiimour
on the front of the chest, just below the manubrium ; or it may burst into the pericar-
dium, may compress or even open into the right lung, the trachea, bronchi, or oesophagus.
Eegarding the transverse part of the ai'ch, the student is reminded that the vessel lies
on the trachea, the oesophagus, and thoracic duct ; that the recurrent laryngeal nerve
winds around it ; and that from its upper part are given off" three large trunks, which
supply the head, neck, and upper extremities. Now an aneurismal tumour taking origin
from the posterior part or right aspect of the vessel, its most usual site, may press upon
the trachea, impede the breathing, or produce cough, hsemoptysis, or stridulous breathing,
or it may ultimately burst into that tube, producing fatal haemorrhage. Again, its pressure
on the laryngeal nerves may give rise to symptoms which so accurately resemble those of
laryngitis, that the operation of tracheotomy has in some cases been resorted to from the
supposition that disease existed in the larynx ; or it may press upon the thoracic duct,
and destroy life by inanition ; or it may involve the ossophagus, producing dysphagia ; or
may burst into this tube, when fatal hsemorrhage will occur. Again, the innominate artery,
or the left carotid, or subclavian, may be so obstructed by clots, as to produce a weakness,
or even a disappearance, of the pulse in one or the other wrist ; or the tumour may present
itself at or above the manubrium, generally either in the median line, or to the right of the
sternum.
Aneurism affecting the descending part of the arch is usually directed backwards and to
the left side, causing absorption of the vertebrae and corresponding ribs ; or it may press
upon the trachea, left bronchus, oesophagus, and the right and left lungs, generally the
latter : when rupture of the sac occurs, this usually takes place in the left pleural cavity ;
less frequently in the left bronchus, the right pleura, or into the substance of the lungs or
trachea. In this form of aneurism, pain is almost a constant and characteristic symptom,
existing either in the back or chest, and usually radiating from the spine around the left
side. This symptom depends upon the aneurismal sac compressing the intercostal nerves
against the bone.
CORONARY.
Branches of the Arch op the Aorta (figs. 187, i 88).
313
The branches given off from the arch of the aorta are five in number. Two
of small size from the ascending portion, the right and left coronary; and three of
large size from the transverse portion, the innominate artery, the left carotid, and
the left subclavian.
Peculiarities. Position of the Branches. The branches, instead of arising from the highest
part of the arch (their usual position), may be moved more to the right, arising from the
commencement of the transverse or upper part of the ascending portion ; or the distance
from one another at their origin may be increased or diminished, the most frequent change
in this resjpect being the approximation of the left carotid, towards the innominate
artery.
The Nximher of the primary branches may be reduced to two : the left carotid arising
from the innominate artery ; or (more rarely), the carotid and subclavian arteries of the
left side arising from an innominate artery. But the number may be increased to four,
from the right carotid and subclavian arteries arising directly from the aorta, the innomi-
nate being absent. In most of these latter cases, the right subclavian arose from the left
end of the arch ; in other cases, it was the second or third branch given off instead of the
first. Lastly, the number of trunks from the arch may be increased to five or six ; in these
instances, the external and internal carotids arose separately from the arch, the common
carotid being absent on one or both sides.
Number usual, Arrangement different. When the aorta arches over to the right side, the
three branches have an arrangement the reverse of what is usual, the innominate supply-
ing the left side ; and the carotid and subclavian (which arise separately), the right side.
In other cases, where the aorta takes its usual course, the two carotids may be joined in a
common trunk, and the subclavians arise separately from the arch, the right subclavian
generally arising from the left end of the arch.
Secondary Branches sometimes arise from the arch ; most commonly it is the left ver-
tebral, which usually takes origin between the left carotid, and left subclavian, or beyond
them. Sometimes, a thyi'oid branch is derived from the arch, or the right internal mam-
mary, or left vertebral, or, more rarely, both vertebrals.
The Coronary Arteries.
The coronary arteries supply the heart; they are two in number, right and
left, arising near the commencement of the aorta immediately above the free
margin of the semi-lunar valves.
The Right Coronary Artery, about the size of a crow's quill, arises from the
aorta immediately above the free margin of the right semi-lunar valve, between
the pulmonary artery, and the appendix of the right auricle. It passes forwards
to the right side in the groove between the right auricle and ventricle, and curving
around the right border of the heart, runs along its posterior surface as far as the
posterior inter- ventricular groove, where it divides into two branches, one of which
continues onwards in the groove between the left auricle and ventricle, and ana-
stomoses with the left coronary; the other descends along the posterior inter-
ventricular furrow, supplying branches to both ventricles, and to the septum,
and anastomosing at the apex of the heart with the descending branch of the left
coronary.
This vessel sends a large branch along the thin margin of the right ventricle
to the apex, and numerous small branches to the right auricle and ventricle, and
commencement of the pulmonary artery.
The Left Coronary, smaller than the former, arises immediately above the free
edge of the left semi-lunar valve, a little higher than the right; it passes forwards
between the pulmonary artery and the left appendix auriculae, and descends ob-
liquely towards the anterior inter-ventricular groove, where it divides into two
branches. Of these, one passes transversely outwards in the left auriculo-ventri-
cular groove, and winds around the left border of the heart to its posterior surface,
where it anastomoses with the superior branch of the right coronary; the other
descends along the anterior inter-ventricular groove to the apex of the heart,
where it anastomoses with the descending branch of the right coronary. The left
coronary supplies the left auricle and its appendix, both ventricles, and numerous
small branches to the piilmonary artery, and commencement of the aorta.
314 ARTERIES.
Peculiarities. These vessels occasionally arise by a common trunk, or their number may
be increased to three ; the additional branch being of small size. More rarely, there are
two additional branches.
Arteria Innominata.
The innominate artery is the largest branch given off from the arch of the aorta.
It arises from the commencement of the transverse portion in front of the left
carotid, and ascending obliquely to the upper border of the right sterno-clavicular
articulation, divides into the right carotid and subclavian arteries. This vessel
varies from an inch and-a-half to two inches in length.
Relations. In front, it is separated from the first bone of the sternum by the
Steruo-hyoid and Sterno-thyroid muscles, the remains of the thymus gland, and
by the left innominate and right inferior thyroid veins v^hich cross its root. Behind,
it lies upon the trachea vs^hich it crosses obliquely. On the right side is the right
vena innominata, right pneumogastric nerve, and the pleura; and on the left side,
the remains of the thymus gland, and origin of the left carotid artery..
Plan of the Relations of the Innominate Artery.
In front.
Sternum.
Sterno-hyoid and Sterno-thyroid.
Remains of thymus gland.
Left innominate and right inferior thyroid veins.
Right side. / \ ^ Left side.
Right vena innominata. / Innominate \ Remains of thymus.
Right pneumogastric nerve. [ Artery. ) Left carotid.
Pleura.
Behind.
Trachea.
Peculiarities in point of division. When the bifurcation of the innominate artery varies
from the point above mentioned, it sometimes ascends a considerable distance above the
sternal end of the clavicle ; less frequently it divides below it. In the former class of
cases, its length may exceed two inches ; and, in the latter, be reduced to an inch or less.
These are points of considerable interest for the surgeon to remember in connection with
the operation of including this vessel in a ligature.
Branches. The arteria innominata occasionally supplies a thyroid branch (middle thyroid
artery), which ascends along the front of the trachea to the thyroid gland; and sometimes,
a thymic or bronchial branch. The left carotid is frequently joined with the innominate
artery at its origin. Sometimes, there is no innominate artery, the right subclavian and
right carotid arising directly from the arch of the aorta.
Position. When the aorta arches over to the right side, the innominate is directed to the
left side of the neck, instead of to the right.
Surgical Anatomy. Although the operation of tying the innominate artery, has been
performed by several surgeons, for aneurism of the right subclavian extending inwards as
far as the scalenus, in no instance has it been attended with success. An important fact
has, however, been estabUshed ; viz., that the circulation in the parts supplied by the artery,
can be supported after the operation ; a fact which cannot but encourage surgeons to have
recourse to it whenever the urgency of the case may require it, notwithstanding that it
must be regarded as peculiarly hazardous.
The failure of the operation in those cases where it has been performed, has depended on
subsequent repeated secondary hsemorrhage, or on inflammation of the adjoining pleural
sac and lung. The main obstacles to its performance are, as the student will perceive from
his dissection of this vessel, its deep situation behind and beneath the sternum, and the
number of important structures which surround it in every part.
In order to apply a ligature to this vessel, the patient is placed upon his back, with the
shoulders raised, and the head bent a little backwards, so as to draw out the artery from
behind the sternum into the neck. An incision two inches long is then made along the
anterior border of the Sterno-mastoid muscle, terminating at the sternal end of the clavicle.
COMMON CAROTID.
315
From this jjoint, a second incision is to be carried about the same length along the upper
border of the clavicle. The skin is to be dissected back, and the platysma being exposed,
must be divided on a director : the sternal end of the Sterno-mastoid is now Vjrought into
view, and a director being passed beneath it, and close to its under surface, so as to avoid
any small vessels, it must be divided transversely throughout the greater part of its attach-
ment.
Pressing aside any loose cellular tissue or vessels that may now appear, the Sterno-hyoid
and Sterno-thyroid muscles will be exposed, and must be divided, a director being pre-
viously passed beneath them. The inferior thyroid veins now come into view, and must
be carefully drawn either upwards or downwards, by means of a blunt hook. On no account
should these vessels be divided, as it would add much to the difficulty of the operation,
and endanger its ultimate success. After tearing through a strong fibro-cellular lamina,
the right carotid is brought into view, and being traced downwards, the arteria innominata
is arrived at. The left vena innominata should now be depressed, the right vena innomi-
nata, the internal jugular vein, and pneumogastric nerve drawn to the right side ; and a
curved aneurism needle may then be passed around the vessel, close to its surface, and in
a direction from below upwards and inwards ; care being taken to avoid the right pleural
sac, the trachea, and cardiac nerves. The ligature should be applied to the artery as high
as possible, in order to allow room between it and the aorta for the formation of a coagulum.
It has been seen that the failure of this operation depends either upon repeated secon-
dary haemorrhage, or inflammation of the pleural sac and lung. The importance of avoiding
the thyroid plexus of veins during the primary steps of the operation, and the pleural sac
whilst including the vessel in the ligature, should be most carefully attended to.
Common Carotid Arteries.
The common carotid arteries, although occupying a nearly similar position in
the neck, differ in position, and, consequently, in their relations at their origin.
The right carotid arises from the arteria innominata, behind the right sterno-
clavicular articulation; the left from the highest part of the arch of the aorta.
The left carotid is, consequently, longer and placed more deeply in the thorax. It
will, therefore, be more convenient to describe first the course and relations of
that portion of the left carotid which intervenes between the arch of the aorta and
the left sterno-clavicular articulation (see fig. 187).
The left carotid within the thorax passes obliquely outwards from the arch of
the aorta to the root of the neck. In front, it is separated from the first piece of
the sternum by the Sterno-hyoid and Sterno-thyroid muscles, the left innominate
vein, and the remains of the thymus gland; behind, it lies on the trachea, oeso-
phagus, and thoracic duct. Internally, it is in relation with the arteria innomi-
nata; externally, with the left pneumogastric nerve, cardiac branches of the sym-
pathetic, and left subclavian artery.
Plan of the Eelations of the Left Common Carotid.
Thoracic Portion.
In front.
Sternum.
Sterno-hyoid and Sterno-thyroid muscles.
Left innominate vein.
Eemains of thymus gland.
Internally.
Arteria innominata.
Left
Common
Carotid.
Thoracic
Portion.
Externally.
Left pneumogastric nerve.
Cardiac nerves.
Left subclavian artery.
Behind.
Trachea.
(Esophagus.
Thoracic duct.
In the neck, the two common carotids resemble each other so closely, that one
description will apply to both. Starting from each side of the neck, these vessels
pass obliquely upwards, from behind the sterno-clavicular articulations, to a level
with the upper border of the thyroid cartilage, where they divide into the
3i6
ARTERIES.
external and internal carotids; these names being derived, the former from their
distribution to the external parts of the head and face, the latter from their distri-
bution to the internal parts of the cranium. The course of each vessel is indicated
by a line drawn from the sternal end of the clavicle below, to a point midway be-
tween the angle of the jaw and the mastoid process above.
189. — Surgical Anatomy of the Arteries of the Neck. Eight Side.
FIC.ISO.
FIhii of tJl
Sranelies
ofUie
EXTERNAL CAROTID
At the lower part of the neck the two common carotid arteries are separated
from each other by a very small interval, which corresponds to the trachea; but
at the upper part, the thyroid body, the larynx and pharynx project forwards
between these vessels, and give the appearance of their being placed further back
in this situation. The common carotid artery is contained in a sheath, derived
from the deep cervical fascia, which also encloses the internal jugular vein and
COMMON CAROTID.
317
pneumogastric nerve, the vein lying on the outer side of the artery, and the nerve
between the artery and vein, on a plane posterior to both. On opening the
sheath, these three structures are seen to be separated from one another, each
being enclosed in a separate fibrous investment.
Relations. At the lower part of the neck the common carotid artery is very
deeply seated, being covered by the Platy sma, superficial and deep fasciae, the Sterno-
mastoid, Sterno-hyoid, and Sterno-thyroid muscles, and by the Omo-hyoid oppo-
site the cricoid cartilage; but in the upper part of its course, near its termination,
it is more superficial, being covered merely by the integument, Platysma, the
superficial and deep fascia, and inner margin of the Sterno-mastoid, and is con-
tained in a triangular space, bounded behind by the Sterno-mastoid, above by the
posterior belly of the Digastric, and below by the anterior belly of the Omo-hyoid.
This part of the artery is crossed obliquely from within outwards by the sterno-
mastoid artery; it is also crossed by the superior thyroid veins, which ter-
minate in the internal jugular, and, descending on its sheath in front, is seen
the descendens noni nerve, this filament being joined with branches from the
cervical nerves, which cross the vessel from without inwards. Sometimes the
descendens noni is contained within the sheath. The middle thyroid vein crosses
it about its centre, and the anterior jugular vein below, the latter vessel being
usually placed beneath the Sterno-mastoid. Behind, the artery lies in front of
the cervical portion of the spine, resting first on the Longus colli muscle, then on
the Rectus anticus major, from which it is separated by the sympathetic nerve.
The recurrent laryngeal nerve and inferior thyroid artery cross behind the
vessel at its lower part. Internally, it is in relation with the trachea and
thyroid gland, the inferior thyroid artery and recurrent laryngeal nerve being
interposed; higher up, with the larynx and pharynx. On its outer side are
placed the internal jugular vein and pneumogastric nerve.
At the lower part of the neck, the internal jugular vein on the right side
recedes from the artery, but on the left side it approaches it, and often crosses
its lower part. This arises from the circumstance of the veins on both sides having
to pass towards the right side of the thorax. This is an important fact to bear
in mind during the performance of any operation on the lower part of the left
common carotid artery.
Plan of the Relations of the Common Carotid Artery.
In front.
Integument and fascise. Omo-hyoid.
Platysma. Descendens noni nerve.
Sterno-mastoid. Sterno-mastoid artery.
Sterno-hyoid. Superior and middle thyroid veins.
Sterno-thyroid. Anterior jugular vein.
Externally. ^ ---s. Internally.
Internal jugular vein. / \ Trachea.
Pneumogastric nerve. \ Common \ Thyroid gland.
Recurrent laryngeal nerve.
Inferior thyroid artery.
Larynx.
Pharynx.
Behind.
Longus colli. Sympathetic nerve.
Rectus anticus major. Inferior thyroid artery.
Recurrent laryngeal neve.
Peculiarities as to Origin. The ric/ht common carotid may arise above or below its usual
point (the upper border of the stern o-clavicular articulation). This variation occurs in one
out of about eight cases and a half, and is more frequently above than below the point
stated ; or its origin may be transferred to the arch of the aorta, or it may arise in
conjunction with the left carotid. The left common carotid varies more frequently in its
origin than the right. In the majority of cases it arises with the innominate artery, or
where the innomiuate artery was absent, the two carotids arose usually by a single trunk.
3i8
ARTERIES.
This vessel lias a tendency towards the right side of the arch, occasionally being the iirst
branch given off from the transverse portion. It rarely joins with the left subclavian,
except in cases of transposition of the viscera.
Point of Division. The most important peculiarities of this vessel, in a surgical point of
view, relate to its place of division in the neck. In the majority of cases, this occurs
higher than usual, the artery dividing into two branches opposite the hyoid bone, or even
higher ; more rarely, it occurs below its usual place, opposite the middle of the larynx, or
the lower border of the cricoid cartilage ; and one case is related by Morgagni, where this
vessel, only an inch and a half in length, divided at the root of the neck. Very rarely, the
common carotid ascends in the neck without any subdivision, the internal carotid being
wanting ; and in two cases the common carotid has been found to be absent, the external
and internal carotids arising directly from the arch of the aorta. This peculiarity existed
on both sides in one subject, on one side in another.
Occasional Branches. The common carotid usually gives off no branches, but it occa-
sionally gives origin to the superior thyroid, or a laryngeal branch, the inferior thyroid, or,
more rarely, the vertebral artery.
Surgical Anatomy. The operation of tying the common carotid artery may be necessary
in a wound of that vessel or its branches, in an aneurism, or in a case of pulsating tumour
of the orbit or skull. If the wound involves the trunk of the common carotid itself, it
will be necessary to tie the artery above and below the wounded part. If, however, one of
the branches of that vessel is wounded, or has an aneurismal tumour connected with it, a
ligature may be applied to any part of it, excepting its origin and termination. When the
case is such as to allow of a choice being made, the lower part of the carotid should never
be selected as the spot upon which a ligature should be placed, for not only is the artery in
this situation placed very deeply in the neck, but it is covered by three layers of muscles,
and on the left side the jugular vein, in the great majority of cases, passes obliquely over
its front surface. Neither should the upper end be selected, for here the superior thyroid
veins would give rise to very considerable difficulty in the application of a ligature.
The point most favourable for the operation is opposite the lower part of the larynx,
and here a ligature may be applied on the vessel, either above or below the point where
it is crossed by the Omo-hyoid muscle. In the former situation the artery is most
accessible, and it may be tied there in cases of wounds, or aneurism of any of the large
branches of the carotid ; whilst in cases of aneurism of the upper part of the carotid, that
part of the vessel may be selected which is below the Omo-hyoid. It occasionally happens
that the carotid artery bifurcates below its usual position : if the artery be exposed at its
point of bifurcation, both divisions of the vessel should be tied near their origin, in pre-
ference to tying the trunk of the artery near its termination ; and if, in consequence of
the entire absence of the common carotid, or from its early division, two arteries, the
external and internal carotids, are met with, the ligature should be placed on that vessel
which is found on compression to be connected with the disease.
In this operation, the direction of the vessel and the inner margin of the Sterno-mastoid
are the chief guides to its performance.
To tie the Common Carotid above the Omo-hyoid. The patient should be placed on his
back with the head thrown back ; an incision is to be made, three inches long, in the
direction of the anterior border of the Sterno-mastoid, from a little below the angle of
the jaw to a level with the cricoid cartilage : after dividing the integument, Platysma,
and superficial fascia, the deep fascia must be cut through on a director, so as to avoid
wounding numerous small veins that are usually found beneath. The head may now
be brought forwards so as to relax the parts somewhat, and the margins of the wound
must be held asunder by copper spatulse. The descendens noni nerve is now exposed, and
must be avoided, and the sheath of the vessel having been raised by forceps, is to be
opened over the artery to a small extent. The internal jugular vein will now present itself
alternately distended and relaxed ; this should be compressed both above and below, and
drawn outwards, in order to facilitate the operation. The aneurism needle is now passed
from the outside, care being taken to keep the needle in close contact with the artery, and
thus avoid the risk of injuring the jugular vein, or including the vagus nerve. Before the
ligature is secured, it should be ascertained that nothing but the artery is included in it.
To tie the Common Carotid, helow the Omo-hyoid. The patient should be placed in the same
situation as before. An incision about three inches in length is to be made parallel to the
inner edge of the Sterno-mastoid, commencing on a level with the cricoid cartilage. The
inner border of the Sterno-mastoid having been exposed, the sterno-mastoid artery and a
large vein, the Middle thyroid will be seen, and must be carefully avoided ; the Sterno-
mastoid is to be turned outwards, and the Sterno-hyoid and thyroid muscles inwards. The
deep fascia must now be divided below the Omo-hyoid muscle, and the sheath having been
exposed, must be opened, care being taken to avoid the descendens noni, which here runs
on the inner or tracheal side. The jugular vein and vagus nerve being then pressed to the
outer side, the needle must be passed around the artery from without inwards, great care
being taken to avoid the inferior thyroid artery, the recurrent laryngeal, and sympathetic
nerves which lie behind it.
EXTERNAL CAEOTID.
319
External Carotid Artery.
The external carotid artery (fig. 189), arises opposite tlie upper border of the
thyroid cartilage, and taking a slightly curved course, ascends upwards and for-
wards, and then inclines backwards, to the space between the neck of the condyle
of the lower jaw, and the meatus auditor ius, where it divides into the temporal
and internal maxillary arteries. It rapidly diminishes in size as it ascends the
neck, owing to the number and large size of the branches given off from it. In
the child, it is somewhat smaller than the internal carotid; but in the adult, the
two vessels are of nearly equal size. At its commencement, this artery is more
superficial, and placed nearer the middle line than the internal carotid, and is con-
tained in the triangular space bounded by the Sterno-mastoid behind, the Omo-
hyoid below, and the posterior belly of the Digastric and Stylo-hyoid above; it is
covered by the skin, platysma, deep fascia, and anterior margin of the Sterno-
mastoid, crossed by the hypoglossal nerve, and by the lingual and facial veins; it is
afterwards crossed by the Digastric and Stylo-hyoid muscles, and higher up passes
deeply into the substance of the parotid gland, where it lies beneath the facial
nerve, and by the junction of the temporal and internal maxillary veins.
Internally is the hyoid bone, the wall of the pharynx, and the ramus of the
jaw, from which it is separated by a portion of the parotid gland.
Behind it, near its origin, is the superior laryngeal nerve; and, higher up, it is
separated from the internal carotid by the Stylo-glossus and Stylo-pharyngeus
muscles, the glosso-pharyngeal nerve, and part of the parotid gland.
Plan of the Relations op the External Carotid.
In front.
Integument, platysma.
Superficial and deep fascise.
Hypoglossal nerve.
Lingual and facial veins.
Digastric and Stylo-hyoid muscles.
Facial nerve and parotid gland.
Temporal and maxillary veins.
Behind.
Superior Laryngeal nerve.
Stylo-glossus.
Stylo-pharyngeus.
Glosso-pharyngeal nerve.
Parotid gland.
Internally.
Hyoid bone.
Pharynx.
Parotid gland.
Ramus of jaw.
Surgical Anatomy. The application of a ligature to the external carotid may be required
in cases of wounds of this vessel, or of its branches when these cannot be tied ; this, how-
ever, is an operation very rarely performed, ligature of the common carotid being prefer-
able, on account of the number of branches given off from the external. To tie this vessel
near its origin, below the point where it is crossed by the Digastric, an incision about three
inches in length should be made along the margin of the Sterno-mastoid, from the angle
of the jaw to the cricoid cartilage, as in the operation for tying the common carotid. To
tie the vessel above the Digastric, between it and the parotid gland, an incision should be
made from the lobe of the ear to the great cornu of the Os-hyoides, dividing successively
the skin, platysma, and fascia. By separating the posterior belly of the Digastric and
Stylo-hyoid muscles which are seen at the lower part of the wound, from the parotid gland,
the vessel will be exposed, and a hgature may be applied to it.
Branches. The external carotid artery gives off eight branches, which, for
convenience of description, may be divided into four sets. (See fig. 190, Plan of
the Branches.)
Terminal.
Temporal.
Internal maxillary.
Ascending.
Ascending pha-
ryngeal.
Anterior. Posterior.
Superior thyroid. Occipital.
Lingual. Posterior auricular.
Facial.
The student is here reminded that many variations are met with in the number,
origin, and course of these branches in different subjects; but the above arrange-
ment is that which is found in the great majority of cases.
320 ARTERIES.
The Superior Thyroid Artery (figs. 189 and 194), is the first branch given
off from the external carotid, being derived from that vessel just below the greater
cornu of the hyoid bone. At its commencement, it is quite superficial, being
covered by the integument, fascise, and platysma, and is contained in the triangu-
lar space bounded by the Sterno-mastoid, Digastric, and Omo-hyoid muscles.
After ascending upwards and inwards for a short distance, it curves downwards
and forwards in an arched and tortuous manner to the upper part of the thyroid
gland, passing beneath the Omo-hyoid, Sterno-hyoid, and Sterno-thyroid muscles;
and distributes numerous branches to its anterior surface, anastomosing with its
fellow of the opposite side, and with the inferior thyroid arteries. Besides the
arteries distributed to the muscles and substance of the gland, its branches are
the following.
Hyoid.
Superficial descending branch.
Superior laryngeal.
Crico-thyroid.
The Hyoid is a small branch which runs along the lower border of the os-
hyoides, beneath the Thyro-hyoid muscle; and, after supplying the muscles con-
nected to that bone, forms an arch, by anastomosing with the vessel of the opposite
side.
The Superficial Descending Branch runs downwards and outwards across the
sheath of the common carotid artery, and supplies the Sterno-mastoid and neigh-
bouring muscles and integument. It is of importance that the situation of this
vessel be remembered, in the operation for tying the common carotid artery.
The Superior Laryngeal, larger than either of the preceding, accompanies the
superior laryngeal nerve, beneath the Thyro-hyOid muscle; it pierces the thyro-
hyoidean membrane, and supplies the muscles, mucous membrane, and glands
of the larynx and epiglottis, anastomosing with the branch from the opposite
side.
The Crico-thyroid (Inferior laryngeal) is a small branch which runs trans-
versely across the crico-thyroid membrane, communicating with the artery of the
opposite side. The position of this vessel should be remembered, as it may prove
the source of troublesome hsemorrhage during the operation of laryngotomy.
_ Surgical Anatomy. The superior thyroid, or some of its branches, are occasionally
divided in cases of out throat, giving rise to considerable hsemorrhage. In such cases, the
artery should be secured, the wound being enlarged for that . purpose, if necessary. The
operation may be easily performed, the position of the artery being very superficial, and
the only structures of importance covering it, being a few small veins. The operation of
tying the superior thyroid artery, in bronchocele, has been performed in numerous instances
with partial or temporary success. When, however, the collateral circulation between this
vessel with the artery of the opposite side, and with the inferior thyroid is completely
re-established, the tumour usually regains its former size.
The Lingual Artery (fig. 194) arises from the external carotid between the
superior thyroid and facial; it runs obliquely upwards and inwards to the greater
cornu of the hyoid bone, then passes horizontally forwards parallel with the
great cornu, and, ascending perpendicularly to the under surface of the tongue,
turns forwards on its under surface as far as the tip of that organ, under the name
of the ranine artery.
Relations. Its first, or oblique portion, is superficial, being contained in the tri-
angular inter-muscular space already described, resting upon the Middle constrictor
muscle of the pharynx, and covered in by the Platysma and fascia of the neck.
Its second, or horizontal portion, also lies upon the Middle constrictor, being covered
at first by the tendon of the Digastric, and the Stylo-hyoid muscle, and afterwards
by the Hyo-glossus, the latter muscle separating it from the hypoglossal nerve. Its
third, or ascending portion, lies between the Hyo-glossus and Genio-hyo-glossus
muscles. The fourth, or terminal part, under the name of the ranine, runs along
LINGUAL; FACIAL. 321
the under surface of the tongue to its tip, it is very superficial, being covered only
by the mucous membrane, and rests on the Lingualis on the outer side of the Genio-
hyo-glossus. The hypoglossal nerve lies nearly parallel with the lingual artery,
separated from it, in the second part of its course, by the Ilyo-glossus muscle.
The branches of the lingual artery are the
Hyoid Sublingual.
Dorsalis Linguae. Ranine.
The Hyoid branch runs along the upper border of the hyoid bone, supplying
the muscles attached to it, and anastomosing with its fellow of the opposite
side.
The Dorsalis Lingu<s (fig. 1 94) arises from the lingual artery beneath the Hyo-
glossus muscle; ascending to the dorsum of the tongue, it supplies its mucous
membrane, the tonsil, soft palate, and epiglottis; anastomosing with its fellow from
the opposite side.
The Sublingual, a branch of bifurcation of the lingual artery, arises at the
anterior margin of the Hyo-glossus muscle, and running forwards and outwards
beneath the Mylo-hyoid to the sublingual gland, supplies its substance, giving
branches to the Mylo-hyoid and neighbouring muscles, the mucous membrane of
the mouth and gums.
The Ranine may be regarded as the continuation of the lingual artery; it runs
along the under surface of the tongue, resting on the Lingualis, and covered by the
mucous membrane of the mouth ; it lies on the outer side of the Genio-hyo-glossus,
and is covered in by the Hyo-glossus and Stylo-glossus, accompanied by the gusta-
tory nerve. On arriving at the tip of the tongue, it anastomoses with the artery
of the opposite side. These vessels in the mouth are placed one on each side
of the fraenum.
Surgical Anatomy. The lingual artery may be divided near its origin in cases of cut
throat, a complication that not unfrequently happens in this class of wounds, or severe
haemorrhage which cannot be restrained by ordinary means may ensue from a wound, or
deep ulcer of the tongue. In the former case, the primary wound may be enlarged if ne-
cessary, and the bleeding vessel at once secured. In the latter case, it has been suggested
that the lingual artery should be tied near its origin. If the student, however, will observe
the depth at which this vessel is placed from the surface, the number of important parts
which surround it on every side, and its occasional irregularity of origin, the great difficulty
of such an operation will be apparent ; under such circumstances, it is more advisable
that the external or common carotid should be tied.
Troublesome haemorrhage may occur in the division of the fraenum in children, if the
ranine artery, which lies on each side of it, is cut through. The student should remember
that the operation is always to be performed with a pair of blunt pointed scissors, which
should be so held as to divide the part in the direction downwards and backwards ; the
ranine artery and veins are then avoided.
The Facial Artery (fig. 191) arises a little above the lingual, and ascends
obliquely forwards and upwards, beneath the body of the lower jaw, to the sub-
maxillary gland, in which it is imbedded; this may be called the cervical part of
the artery. It then curves upwards over the body of the jaw at the anterior infe-
rior angle of the Masseter muscle, ascends forwards and upwards across the cheek
to the angle of the mouth, passes up along the side of the nose, and terminates at
the inner canthus of the eye, under the name of the angular artery. This vessel,
both in the neck, and on the face, is remai'kably tortuous; in the former situation,
to accommodate itself to the movements of the pharynx in deglutition; and in the
latter, to the movements of the jaw, and of the lips and cheeks.
Relations. In the neck its origin is superficial, being covered by the integument,
Platysma, and fascia; it then passes beneath the Digastric and Stylo-hyoid muscles,
and the submaxillary gland. On the face, where passing over the body of the
lower jaw, it is comparatively superficial, being covered by the Platysma. In this
situation its pulsation may be distinctly felt, and compression of the vessel effec-
tually made against the bone. In its course over the face, it is covered by the
integument, the fat of the cheek, and, near the angle of the mouth, by the Pla-
tysma and Zygomatic muscles. It rests on the Buccinator, the Levator anguli
Y
322
ARTEEIES.
oris, and the Levator labii superioris alaeque nasi. It is accompanied by the facia L
vein throughout its entire course; the vein is not tortuous like tlie artery, and, on
the face, is separated from that vessel by a considerable interval. The branches
of the facial nerve cross this vessel, and the infra-orbital nerve lies beneath it.
The branches of this vessel may be divided into two sets, those given off below
the jaw (cervical), and those on the face (facial).
Cervical Branches.
Inferior or Ascending Palatine.
Tonsillitic.
Submaxillary.
Submental.
Facial Branches.
Muscular.
Inferior Labial.
Inferior Coronary.
Superior Coronary.
Lateralis Nasi.
Ansrular.
191 . — The Arteries of the Face and Scalp.
-InfbruynJjoital
The Inferior or Ascending Palatine (fig. 194) ascends between the Stylo-
glossus and Stylo-i)haryngeus to the outer side of the pharynx. After supplying
these muscles, the tonsil, and Eustachian tube, it divides near the Levator palati
into two branches, one follows the course of the Tensor palati, supplies the soft
palate and the palatine glands; the other passes to the tonsil, which it supplies;
anastomosing with the tonsillitic artery. These vessels inosculate with the pos-
terior palatine branch of the internal maxillary artery.
FACIAL.
323
The Tonsillitic branch (fig. 194) passes up along the side of the pharynx, and
perforating the Superior constrictor, ramifies in the substance of the tonsil and
root of the tongue.
The Submaxillary consists of three or four large branches, which supply the
submaxillary gland, some being prolonged to the neighbouring muscles, lymphatic
glands, and integument.
The Submental, the largest of the cervical branches, is given off from the facial
artery just as that vessel quits the submaxillary gland; it runs forwards upon the
Mylo-hyoid muscle, just below the body of the jaw, and beneath the Digastric;
after supplying the muscles attached to the jaw, and anastomosing with the sub-
lingual artery, it arrives at the symphysis of the chin, where it divides into a
superficial and a deep branch; the former turns round the chin, and passing
between the integument and Depressor labii inferioris, supplies both, and anasto-
moses with the inferior Labial. The deep branch passes between that muscle and
the bone, supplies the lip; anastomosing with the inferior labial and mental
arteries.
The muscular branches are distributed to the internal Pterygoid, Masse ter, and
Buccinator.
The Inferior Labial passes beneath the Depressor anguli oris, to supply the
muscles and integument of the lower lip, anastomosing with the inferior coronary
and sub-mental branches of the facial, and with the mental branch of the inferior
dental artery.
The Inferior Coronary, is derived from the facial artery near the angle of the
mouth; it passes upwards and inwards beneath the Depressor anguli oris, and,
penetrating the Orbicularis muscle, runs in a tortuous course along the edge of
the lower lip between this muscle and the mucous membrane, inosculating with
the artery of the opposite side. This artery supplies the labial glands, the mucous
membrane, and muscles of the lower lip; and anastomoses with the inferior labial,
and mental branch of the inferior dental artery.
The Superior Coronary is larger, and more tortuous in its course than the pre-
ceding. It follows the same course along the edge of the upper lip, lying between
the mucous membrane and the Orbicularis, and anastomoses with the artery of the
opposite side. It supplies the textures of the upper lip, and gives off in its
course two or three vessels which ascend to the nose. One, named the artery of
the septum, ramifies on the septum of the nares as far as the point of the nose;
another supplies the ala of the nose.
The Lateralis Nasi is derived from the facial, as this vessel is ascending along
the side of the nose; it supplies the ala and dorsum of the nose, anastomosing
with its fellow, the nasal branch of the ophthalmic, the artery of the septum, and
the infra-orbital.
The Angular Artery is the termination of the trunk of the facial; it ascends to
the inner angle of the orbit, accompanied by a large vein, the angular ; it distri-
butes some branches on the cheek which anastomose with the infra-orbital, and
after supplying the lachrymal sac, and Orbicularis muscle, terminates by anasto-
mosing with the nasal branch of the ophthalmic artery.
The anastomoses of the facial artery are very numerous, not only with the
vessel of the opposite side, but with other vessels from different sources ; viz., with
the sub-lingual branch of the lingual, with the mental branch of the inferior dental
as it emerges from the dental foramen, with the ascending pharyngeal and posterior
palatine, and with the ophthalmic, a branch of the internal carotid; it also inoscu-
lates with the transverse facial, and with the infra-orbital.
Peculiarities. The facial artery not unfrequently arises by a common trunk with the lin-
gual. This vessel also is subject to some variations in its size, and in the extent to which
it supplies the face. It occasionally terminates as the submental, and not unfrequently
suppHes the face only as high as the angle of the mouth or -nose. The deficiency is then
supplied by enlargement of one of the neighbouring arteries.
Y 2
324 ARTERIES.
Surgical Anatomy. The passage of the facial artery over the body of the jaw would ap-
pear to afford a favourable position for the application of pressure in cases of haemorrhage
from the lips, the result either of an accidental wound, or from an operation ; but its ap-
plication is useless, on account of the free communication of this vessel with its fellow,
and with numerous branches from different sources. In a wound involving the lip, it is
better to seize the part between the fingers and evert it, when the bleeding vessel may be
at once secured with a tenaculum. In order to prevent heemorrhage in cases of excision,
or in the removal of diseased growths from the part, the lip should be compressed on each
side between the finger and thumb, whilst the surgeon excises the diseased part. In order
to stop hemorrhage where the lip has been divided in an operation, it is necessary in uniting
the edges of the wound, to pass the sutures through the cut edges, almost as deep as its
mucous surface ; by these means, not only are the cut surfaces more neatly adapted to
each other, but the possibility of haemorrhage is prevented by including in the suture the
divided artery. If the suture is, on the contrary, passed through merely the cutaneous
portion of the wound, heemorrhage occurs into the cavity of the mouth. The student
should, lastly, observe the relation of the angular artery to the lachrymal sac, and it will
be seen that, as the vessel passes up along the inner margin of the orbit, it ascends on its
nasal side. In operating for fistula lachrymalis, the sac should always be opened on its
outer side, in order that this vessel should be avoided.
The Occipital Artery arises from the posterior part of the external carotid,
opposite the facial, near the lower margin of the Digastric muscle. At its origin,
it is covered by the posterior belly of the Digastric and Stylo-hyoid muscles, and
part of the parotid gland, the hypo-glossal nerve winding around it from behind
forwards; higher up, it passes across the internal carotid artery, the internal jugular
vein, and the pneumogastric and spinal accessory nerves; it then ascends to the
interval between the transverse process of the atlas, and the mastoid process of
the temporal bone, passes horizontally backwards, grooving the surface of the latter
bone, being covered by the Sterno-mastoid, Splenius, Digastric, and Trachelo-
mastoid muscles, resting upon the Complexus, Superior oblique, and Rectus pos-
ticus major muscles; it then passes vertically upwards, piercing the cranial at-
tachment of the Trapezius, and ascends in a tortuous course on the occiput as
high as the vertex, where it divides into numerous branches.
The branches given off from this vessel are,
Muscular. Inferior meningeal.
Auricular. Arteria princeps cervicis.
Tlie Muscular Branches supply the Digastric, Stylo-hyoid, Sterno-mastoid,
Splenius, and Trachelo-mastoid muscles. The branch distributed to the Sterno-
mastoid is of a large size.
The Atcricular Branch supplies the back part of the concha.
The 3Ieni?igeal Branch, ascends with the internal jugular vein, and enters the
skull through the foramen lacerum posterius, to supply the dura mater i^ the 71.
posterior fossa.
The Arteria Princeps Cervicis (fig. 1 94), is a large vessel which descends along
the back part of the neck, and divides into a superficial and deep branch. The
former runs beneath the Splenius, giving off branches which perforate that muscle
to supply the Trapezius, anastomosing with the superficial cervical artery; the
latter passes beneath the Complexus, between it and the Semi-spinalis colli, and
anastomoses with the vertebral, and deep cervical branch of the superior inter-
costal. The anastomosis between this vessel and the profunda cervicis serves
mainly to establish the collateral circulation after ligature of the carotid or
subclavian artery.
The cranial branches of the occipital artery are distributed upon the occiput;
they are very tortuous, and lie between the integument and Occipito-frontalis,
anastomosing with their fellows of the opposite side, the posterior auricular, and
temporal arteries. They supply the posterior part of the Occipito-frontalis muscle,
the integument, pericranium, and one or two branches occasionally pass through the
parietal or mastoid foramina, to supply the dura mater.
The Posterior Auricular Artery (fig. 191) is a small vessel, which arises
from the external carotid, above the Digastric and Stylo-hyoid muscles, opposite
I
OCCIPITAL; POSTERIOR AURICULAR; PHARYNGEAL. 325
the apex of the styloid process. It ascends, under cover of the parotid gland, to
the groove between the cartilage of the ear and the mastoid process, immediately
above Avhich it divides into two branches, an anterior, which passes forwards to
anastomose with the posterior division of the temporal, and a posterior, which
communicates with the occipital. Just before arriving at the mastoid process,
this artery is crossed by the portio dura, and has beneath it the spinal accessory
nerve.
Besides several small branches to the Digastric, Stylo-hyoid, and Sterno-mas-
toid muscles, and to the parotid gland, this vessel gives off two branches.
Stylo-mastoid. Auricular.
The Stylo-mastoid Branch enters the stylo-mastoid foramen, and supplies the
tympanum, mastoid cells, and semi-circular canals. In the young subject, a
branch from this vessel forms, with the tympanic branch from the internal
maxillary, a delicate vascular circle, which surrounds the auditory meatus, and
from which delicate vessels ramify on the membrana tympani.
The Auricular Branch is distributed to the posterior part of the cartilao-e
of the ear, upon which it minutely ramifies, some branches curving round its
margin, others perforating the fibre- cartilage, to supply its anterior surface.
The Ascending Phakyngeal Artery (fig. 194), the smallest branch of the
external carotid, is a long slender vessel, deeply seated in the neck, beneath the
other branches of the external carotid and Stylo-pharyngeus muscle. It arises
from the posterior part of the external carotid, and ascends the neck to the under
surface of the base of the skull. It lies upon the Rectus capitis anticus major,
between the internal carotid, and the outer wall of the pharynx. Its branches
may be subdivided into three sets: I. Those directed outwards to supply
muscles and nerves. 2. Those directed inwards to the pharynx. 3. Meningeal
branches.
External. Pharyngeal.
Meningeal.
The External Branches are numerous small vessels, which supply the Recti
antici muscles, the sympathetic, lingual, and pneumogastric nerves, and the
lymphatic glands of the neck, anastomosing with the ascending cervical branch
of the subclavian artery.
The Pharyngeal Branches are three or four in number. Two of these descend
to supply the Middle and Inferior constrictors and the Stylo-pharyngeus, ramifying
in their substance and in the mucous membrane lining them. The largest of the
pharyngeal branches passes inwards, running upon the Superior constrictor, and
sending ramifications to the soft palate, Eustachian tube, and tonsil, taking the
place of the ascending palatine branch of the facial artery, when that vessel is
of small size.
The Meningeal Branches consist of several small vessels, which pass through
foramina in the base of the skull, to supply the dura mater. One, the posterior
meningeal, enters the cranium through the foramen lacerum posterius with the
internal jugular vein. A second passes through the foramen lacerum basis cranii;
and occasionally a third through the anterior condyloid foramen. They are all
distributed to the dura mater.
The Temporal Artery (fig. 191), the smaller of the two terminal branches
of the external carotid, appears, from its direction, to be the continuation of that
vessel. It commences in the substance of the parotid gland, in the interspace
between the neck of the condyle of the lower jaw and the external meatus; cross-
ing over the root of the Zygoma, immediately beneath the integument, it divides
about two inches above the zygomatic arch into two branches, an anterior and a
posterior.
The Anterior Temporal inclines forwards over the forehead, supplying the
muscles, integument, and pericranium in this region, and anastomoses with the
326 ARTERIES.
supra-oi'bital and frontal arteries, its branches being directed from before back-
wards.
The Posterior Temporal, larger than the anterior, curves upwards and back-
wards along the side of the head, lying above the temporal fascia, and inosculates
with its fellow of the opposite side, and with the posterior auricular and occipital
arteries.
The temporal artery, as it crosses the zygoma, is covered by the Attrahens
aurem muscle, and by a dense fascia given off from the parotid gland; it is also
usually crossed by one or two veins, and accompanied by branches of the facial
nerve. Besides some twigs to the parotid gland, the articulation of the jaw, and
to the Masseter muscle, its branches are the
Transverse facial. Middle temporal.
Anterior auricular.
The Transverse Facial is given off from the temporal before that vessel quits
the parotid gland; running forwards through its substance, it passes transversely
across the face, between Stenon's duct and the lower border of the zygoma, and
divides on the side of the face into numerous branches, which supply the parotid
gland, the Masseter muscle, and the integument, anastomosing with the facial
and infra-orbital arteries. This vessel rests on the Masseter, and is accom-
panied by one or two branches of the facial nerve.
The Middle Temporal Artery arises immediately above the zygomatic arch, and
perforating the temporal fascia, supplies the Temporal muscle, anastomosing with
the deep temporal branches of the internal maxillary. It occasionally gives off
an orbital branch, which runs along the upper border of the zygoma, between the
two layers of the temporal fascia, to the outer angle of the orbit; it supplies the
Orbicularis, and anastomoses with the lachrymal and palpebral branches of the
ophthalmic artery.
The Anterior Auricular Branches are distributed to the anterior portion of the
pinna, the lobule, and part of the external meatus, anastomosing with branches
of the posterior auricular.
Surgical Anatomy. It occasionally happens that the surgeon is called upon to perform
the operation of arteriotomy upon this vessel in cases of inflammation of the eye or brain.
Under these circumstances, the anterior branch is the one usually selected. If the student
will consider the relations of the trunk of this vessel with the surrounding structures, as
it crosses the zygomatic arch, he will observe that it is covered by a thick and dense fascia,
crossed by one or two veins, and accompanied by branches of the facial and temporo-
auricular nerves. Bleeding should not be performed in this situation, as considerable diffi-
culty may arise from the dense fascia covering this vessel preventing a free flow of blood,
and considerable pressure is requisite afterwaids to repress it. Again, a varicose aneurism
may >be formed by the accidental opening of one of the veins covering it ; or severe
neuralgic pain may arise from the operation implicating one of the nervous filaments
which accompany the artery.
The anterior branch, is, on the contrary, subcutaneous, is a large vessel, and as readily
compressed as any other portion of the artery ; it should consequently always be selected
for the operation.
The Internal Maxillary, the larger of the two terminal branches of the
external carotid, passes inwards, at right angles from that vessel, behind the neck
of the lower jaw, to supply the deep structures of the face. At its origin, it is
imbedded in the substance of the parotid gland, being on a level with the lower
extremity of the lobe of the ear.
In the first part of its course (maxillary portion), the artery passes horizon-
tally forwards and inwards, between the ramus of the jaw, and the internal
lateral ligament. The artery here lies parallel with the auricular nerve; it
crosses the inferior dental nerve, and lies beneath the narrow portion of the
External pterygoid muscle.
In the second part of its course (pterygoid portion), it ascends obliquely for-
wards and upwards upon the outer surface of the External pterygoid muscle, being
TEMPORAL; INTERNAL MAXILLARY.
327
In the third part of its course (spheno-maxillary portion), it approaches the
superior maxillary bone, crosses the interval between the two heads of the Exter-
nal pterygoid, and enters the spheno-maxillary fossa, where it lies in relation
with Meckel's ganglion, and gives off its terminal branches.
Peculiarities. Occasionally, this artery passes between the two Pterygoid muscles. The
vessel in this case passes forwards to the interval between the two heads of the External
pterygoid, in order to reach the maxillary bone. Sometimes, the vessel escapes from be-
neath the External pterygoid by perforating the middle of this muscle.
192. — The Internal Maxillary Artery, and its Branches.
0 'Palatini
Wterygo -Pi
FICr.193. Elan of the £Tanches UH'^L""" j „ , ,■
•* I ^( \Descc7ldtng Fulatino
tS/ilum Palatine.
flflddU Meni-nffeal
McTiftif/ca Pawn
Tumhanic-
JifeTlCT Senfa/-
The branches of this vessel may be divided into three groups, corresponding
with its three divisions.
Branches from the Maxillary Portion.
Tympanic.
Middle meningeal.
Small meningeal.
Inferior dental.
The Tympanic Branch passes upwards behind the articulation of the lower
jaw, enters the tympanum through the fissura Glaseri, supplies the Laxator tym-
pani, and ramifies upon the membrana tympani, anastomosing with the stylo-
mastoid and Vidian arteries.
The Middle Meningeal is the largest of the branches which supply the dura
328 ARTERIES.
mater. It arises from the internal maxillary between the internal lateral ligament,
and the neck of the jaw, and ascends vertically upwards to the foramen spinosum
in the spinous process of the sphenoid bone. On entering the cranium, it divides
into two branches, an anterior, and a posterior. The anterior branch, the larger,
crosses the great ala of the sphenoid, and reaches the groove, or canal, in the an-
terior inferior angle of the parietal bone; it then divides into branches which
spread out between the dura mater and internal surface of the cranium, some
passing upwards over the parietal bone as far as the vertex, and others backwards
to the occipital bone. The posterior branch crosses the squamous portion of the
temporal, and on the inner surface of the parietal bone divides into branches which
supply the posterior part of the dura mater and cranium. The branches of this
vessel are distributed to the dura mater, but chiefly to the bones; they anastomose
with the arteries of the opposite side, and with the anterior and posterior
meningeal.
The middle meningeal, on entering the cranium, gives off the following colla-
teral branches: I. Numerous small vessels to the ganglion of the fifth nerve,
and to the dura mater in this situation. 2. A branch to the facial nerve, which
enters the hiatus Fallopii, supplies the facial nerve, and anastomoses with the stylo-
mastoid branch of the occipital artery. 3. Orbital branches, which pass through
the sphenoidal fissure, or through separate canals in the great wing of the sphe-
noid, to anastomose with the lachrymal or other branches of the ophthalmic artery.
4. Temporal branches, which pass through foramina in the great wing of the
sphenoid, and anastomose in the temporal fossa with the deep temporal arteries.
The Small Meningeal is sometimes derived from the preceding. It enters the
skull through the foramen ovale, and supplies the Casserian ganglion and dura
mater. Before entering the cranium, it gives off a branch to the nasal fossa and
soft palate.
The Inferior Dental descends with the dental nerve, to the foramen on the
inner side of the ramus of the jaw. It runs along the dental canal in the sub-
stance of the bone, accompanied by the nerve, and opposite the bicuspid tooth di-
vides into two branches, an incisor, which is continued forwards beneath the incisor
teeth as far as the symphysis, where it anastomoses with the artery of the opposite
side; the other, the mental, escapes with the nerve at the mental foramen, supplies
the structures composing the chin, and anastomoses with the submental, inferior
labial, and inferior coronary arteries. As the dental artery enters the foramen, it
gives off a mylo-hyoid branch, which runs in the mylo-hyoid groove, and ramifies
on the under surface of the Mylo-hyoid nuiscle. The dental and incisor arteries
during their course through the substance of the bone, give off a few twigs which
are lost in the diploe, and a series of branches which correspond in number to the
roots of the teeth; these enter the minute apertures at the extremities of the
fangs, and ascend to supply the pulp of the teeth.
Branches of the Second, or Pterygoid Portion,
Deep temporal. Masseteric,
Pterygoid. Buccal,
These branches are distributed, as their names imply, to the muscles in the
maxillary region.
The Deep Temporal Branches, two in number, anterior, and posterior, each
occupy that part of the temporal fossa indicated by its name. Ascending between
the Temporal muscle and pericranium, they supply that muscle, and anastomose
with the other temporal arteries. The anterior branch communicating with the
lachrymal through small branches which perforate the malar bone.
The Pterygoid Branches, irregular in their number and origin, supply the
Pterygoid muscles.
The Masseteric is a small branch which passes outwards above the sigmoid
INTERNAL MAXILLARY.
329
notch of the loAver jaw, to the deep surface of the Masseter. It supplies that
muscle, and anastomoses with the masseteric branches of the facial and transverse
facial arteries.
The Buccal is a small branch which runs obliquely forwards between the Inter-
nal pterygoid, and the ramus of the jaw, to the outer surface of the Buccinator,
to which it is distributed, anastomosing with branches of the facial artery.
Branches of the Third, or Spheno-maxillary Portion.
Alveolar, Vidian.
Infra-orbital. Pterygo-palatine.
Posterior or Descending palatine. Nasal or Spheno-palatine.
The Alveolar is given off from the internal maxillary by a common branch
with the infra-orbital, and just as the trunk of the vessel is passing into the
spheno-maxillary fossa. Descending upon the tuberosity of the superior maxillary
bone, it divides into numerous branches; one, the superior dental, larger than the
rest, supplies the molar and bicuspid teeth; its branches entering the foramina in
the alveolar process, some branches pierce the bone to supply the lining of the
antrum, and others are continued forwards on the alveolar process to supply the
gums.
The Infra-orbital appears, from its direction, to be the continuation of the trunk
of the internal maxillary. It arises from that vessel by a common trunk with the
preceding branch, and runs along the infra-orbital canal with the superior maxillary
nerve, emei'ging upon the face at the infra-orbital foramen, beneath the Levator
labii superioris. Whilst contained in the canal, it gives off branches which ascend
into the orbit, and supply the Inferior rectus, and Inferior oblique muscles, and
the lachrymal gland. Other branches descend through canals in the bone, to
supply the mucous membrane of the antrum, and the front teeth of the upper jaw.
On the face, it supplies the lachrymal sac, and inner angle of the orbit, anasto-
mosing with the facial and nasal branch of the ophthalmic arteries; and other
branches descend beneath the elevator of the upper lip, and anastomose with the
transverse facial and buccal branches.
The four remaining branches arise from that portion of the internal maxillary
which is contained in the spheno-maxillary fossa.
The Descending Palatine passes down along the posterior palatine canal with the
posterior palatine branches of Meckel's ganglion, and emerging from the posterior
palatine foramen, runs forwards in a groove on the inner side of the alveolar bor-
der of the hard palate, to be distributed to the gums, the mucous meaibrane of the
hard palate, and palatine glands. Whilst it is contained in the palatine canal, it
gives off branches, which descend in the accessory palatine canals to supply the
soft palate, anastomosing with the ascending palatine artery; and anteriorly it ter-
minates in a small vessel, which ascends in the anterior palatine canal, and anasto-
moses with the artery of the septum, a branch of the spheno-palatine.
The Vidian Branch passes backwards along the Vidian canal with the Vidian
nerve. It is distributed to the upper part of the pharynx and Eustachian tube,
sending a small branch into the tympanum.
The Ptery go- Palatine is also a very small branch, which passes backwards
through the pterygo-palatine canal with the pharyngeal nerve, and is distributed
to the upper part of the pharynx and Eustachian tube.
The Nasal or Spheno- Palatine passes through the spheno-palatine foramen
into the cavity of the nose, at the back part of the superior meatus, and divides
into two branches; one internal, the artery of the septum, passes obliquely down-
wards and forwards along the septum nasi, supplies the mucous membrane, and
anastomoses in front with the ascending branch of the descending palatine. The
external branches, two or three in number, supply the mucous membrane covering
the lateral wall of the nares, the antrum, and the ethmoid and sphenoid cells.
330 SUEGICAL ANATOMY.
Surgical Anatomy of the Triangles of the Neck.
The student having studied the relative anatomy of the large arteries of the
neck and their branches, and the relations they bear to the veins and nerves, should
now examine these structures collectively, as they present themselves in certain
regions of the neck, in each of which important operations are being constantly
performed.
For this purpose, the Sterno-mastoid, or any other muscles that have been
divided in the dissection of these vessels, should be replaced in their normal posi-
tion, the head should be supported by placing a block at the back of the neck, and
the face turned to the side opposite to that which is being examined.
The side of the neck presents a somewhat quadrilateral outline, limited, above,
by the lower border of the body of the jaw, and an iinaginary line extending from
the angle of the jaw to the mastoid process; below, by the prominent upper bor-
der of the clavicle; in front, by the median line of the neck; behind, by the ante-
rior margin of the Trapezius muscle. This space is subdivided into two large
triangles by the Sterno-mastoid muscle, which passes obliquely across the neck,
from the sternum and clavicle, below, to the mastoid process, above. The anterior
margin of this muscle forms a prominent ridge beneath the skin, which serves as
a guide to the surgeon in the operation for applying a ligature to the common
carotid artery, or in oesophagotomy. The triangular space in front of this muscle
is called the anterior triangle, and that behind it, the posterior triangle.
Anterior Triangular Space.
The anterior triangle is limited, in front, by a line extending from the chin to
the sternum; behind, by the anterior margin of the Sterno-mastoid; its base,
directed upwards, is formed by the lower border of the body of the jaw, and a
line extending from the angle of the jaw to the mastoid process; its apex is formed
below by the sternum. This space is covered in by the integument, superficial
fascia, Platysma, deep fascia, crossed by branches of the facial and superficial cer-
vical nerves; and subdivided into three smaller triangles by the Digastric muscle,
above, and the anterior belly of the Omo-hyoid, below. These are named, from
below upwards, the inferior carotid triangle, the superior carotid triangle, and the
submaxillary triangle.
Each of these spaces must now be separately examined.
The Inferior Carotid Triangle is limited, in front, by the median line of the
neck; behind, by the anterior margin of the Sterno-mastoid; above, by the ante-
rior belly of the Omo-hyoid; and it is covered in by the integument, Platysma,
superficial and deep fascize; ramifying between which, is seen the cutaneous
descending branch of the superficial cervical nerve. Beneath these superficial
structures, are the Sterno-hyoid and Sterno-thyroid muscles, which, together with
the anterior margin of the Sterno-mastoid, conceal the lower part of the com-
mon carotid artery. This vessel is enclosed within its sheath, together with
the internal jugular vein and pneumogastric nerve; the vein lying on the outer
side of the artery on the right side of the neck, but overlapping it, or passing
directly across it on the left side; the nerve lying between the artery and vein, on
a plane posterior to both. In front of the sheath are a few filaments descending
from the loop of communication between the descendens and communicans noni;
behind the sheath is seen the inferior thyroid artery, the recurrent laryngeal and
sympathetic nerves; and on its inner side, the trachea, the thyroid gland, much
more prominent in the female than in the male, and the lower part of the larynx.
In the upper part of this space, the common carotid artery may be tied below the
Omo-hyoid muscle.
The Superior Carotid Triangle is bounded, behind, by the Sterno-mastoid;
below, by the anterior belly of the Omo-hyoid; and above, by the posterior belly
of the Digastric muscle. Its floor is formed by parts of the Thyro-hyoid, Hyo-
glossus, and the inferior and middle Constrictor muscles of the pharynx; and it is
OF THE TRIANGLES OF THE NECK. 331
covered in by the integument, Platysma, superficial and deep fasciae; ramifyino-
between which, are branches of the facial and superficial cervical nerves. This
space contains the upper part of the common carotid artery, which bifurcates
opposite the upper border of the thyroid cartilage into the external and internal
carotid. These vessels are concealed from view by the anterior margin of the
Sterno-mastoid muscle, which overlaps them. The external and internal carotids
lie side by side, the external being the most anterior of the two. The following
branches of the external carotid are also met with in this space; the superior
thyroid, which runs forwards and downwards; the lingual, which passes directly
forwards; the facial, forwards and upwards; the occipital is directed backwards;
and the ascending pharyngeal runs directly upwards on the inner side of the
internal carotid. The veins met with are, the internal jugular which lies on the
outer side of the common and internal carotid vessels, and veins correspondino' to
the above mentioned branches of the external carotid, viz., the superior and middle
thyroid, the lingual, facial, ascending pharyngeal, and sometimes the occipital; all
of which accompany their corresponding arteries, and terminate in the internal
jugular. Li front of the sheath of the common carotid is the descendens noni, the
hypo-glossal, from which it is derived, crossing both carotids above, curving around
the occipital artery at its origin. Within the sheath, between the artery and vein,
and behind both, is the pneumogastric nerve; behind the sheath, the sympathetic.
On the outer side of the vessels the spinal accessory nerve runs for a short distance
before it pierces the Sterno-mastoid muscle; and on the inner side of the internal
carotid, just below the hyoid bone, may be seen the superior laryngeal nerve; and
still more inferiorly, the external laryngeal nerve. The upper part of the larynx
and the pharynx, are also found in the front part of this space.
The Submaxillary Triangle corresponds to that part of the neck immediately
beneath the body of the jaw. It is bounded above, by the lower border of the
body of the jaw, the parotid gland, and mastoid process; behind, by the posterior
belly of the Digastric and Stylo-hyoid muscles ; in front, by the middle line of the
neck. The floor of this space is formed by the anterior belly of the Digastric,
the Mylo-hyoid, and Hyo-glossus muscles; and it is covered in by the integument,
Platysma, superficial and deep fasciae; ramifying between which, are branches of
the facial and ascending filaments of the superficial cervical nerve. This space
contains, in front, the submaxillary gland, imbedded in which, are the facial
artery and vein, and their glandular branches; beneath this gland, on the sur-
face of the Mylo-hyoid muscle, are the submental artery, and the mylo-hyoid artery
and nerve. The posterior part of this space is sej)arated from the anterior part, by
the stylo-maxillary ligament, it contains the external carotid artery, ascendino-
deeply in the substance of the parotid gland; this vessel here lies in front of and
superficial to the internal carotid, being crossed by the facial nerve, and giving off
in its course the posterior auricular, temporal and internal maxillary branches;
more deeply seated is the internal carotid, the internal jugular vein, and the
pneumogastric nerve, separated from the external carotid, by the Stylo-glossus and
Stylo-pharyngeus muscles, and the glosso-pharyngeal nerve.
Posterior Triangular Space.
The posterior triangular space is bounded in front by the Sterno-mastoid
muscle, behind, by the anterior margin of the Trapezius; its base corresponds to
the upper border of the clavicle, its apex to the occiput. This space is crossed
about an inch above the clavicle by the posterior belly of the Omo-hyoid, which
divides it unequally into two, an upper or occipital, and a lower or subclavian.
■ The Occipital, the larger of the two posterior triangles, is bounded in front by
the Sterno-mastoid; behind by the Trapezius; below by the Omo-hyoid. Its
floor is formed from above downwards by the Splenius, Levator anguli scapulae,
and the Middle and Posterior scaleni muscles. It is covered in by the integu-
ment, the Platysma below, the superficial and deep fascise, and crossed, above,
by the ascending branches of the cervical plexus, the spinal accessory nerve is
332 ARTERIES.
directed obliquely across the space from the Sterno-mastoid, which it pierces, to
the under surface of the Trapezius; below, it is crossed by the ascending branches
of the same plexus and transversalis colli artery and vein. A chain of lymphatic
glands is also found running along the posterior border of the Sterno-mastoid,
from the mastoid process to the root of the neck.
The Subclavian, the smaller of the two posterior triangles, is bounded, above,
by the posterior belly of the Omo-hyoid; below, by the clavicle; its base, directed
forwards, being formed by the Sterno-mastoid. The size of this space varies
according to the extent of attachment of the clavicular portion of the Sterno-
mastoid and Trapezius muscles, and also according to the height at which the Omo-
hyoid crosses the neck above the clavicle. The height also of this space varies
much, according to the position of the arm, being much diminished on raising the
limb, on account of the ascent of the clavicle, and increased on drawing the arm
downwards, when this bone is consequently depressed. This space is covered in
by the integument, the superficial and deep fasciae, and crossed by the descending
branches of the cervical plexus. Passing across it, just above the level of the
clavicle, is the third portion of the subclavian artery, which curves outwards and
downwards from the outer margin of the Scalenus anticus, across the first rib, to
the axilla. Sometimes this vessel rises as high as an inch and a half above the
clavicle, or to any point intermediate between this and its usual level. Occasion-
ally it passes in front of the Scalenus anticus, or pierces the fibres of this muscle.
The subclavian vein lies beneath the clavicle, and is usually not seen in this
space; but it occasionally rises as high up as the artery, and has even been seen
to pass with that vessel behind the Scalenus anticus. The brachial plexus of
nerves lies above the artery, and in close contact with it. Passing transversely
across the clavicular margin of the space are the supra- scapular vessels, and
traversing its upper angle in the same direction, the transverse cervical vessels.
The external jugular vein descends vertically downwards behind the posterior
border of the Sterno-mastoid, to terminate in the Subclavian ; it receives the trans-
verse cervical and supra-scapular veins, which occasionally form a plexus in front
of the artery, and a small vein which crosses the clavicle from the cephalic. The
small nerve to the Subclavius also crosses this space about its centre.
Internal Carotid Artery.
The internal carotid artery commences at the bifurcation of the common carotid,
opposite the upper border of the thyroid cartilage, and ascends perpendicularly
upwards, in front of the transverse processes of the three upper cervical vertebra,
to the carotid foramen in the petrous portion of the temporal bone. After ascend-
ing in it for a short distance, it passes forwards and inwards through the carotid
canal, and ascending a little by the side of the sella Turcica, curves upwards by
the anterior clinoid process, where it pierces the dura mater, and divides into its
terminal branches.
This vessel supplies the anterior part of the brain, the eye, and its appendages.
Its size in the adult is equal to that of the external carotid; in the child it is
larger than that vessel. It is remarkable for the number of curvatures that it
presents in different parts of its course. In its cervical portion it occasionally
presents one or two flexures near the base of the skull, whilst through the rest of
its extent it describes a double curvature, which resembles the italic letter /
placed horizontally (>o. These curvatures most probably diminish the velocity of
the current of blood, by increasing the extent of surface over which it moves, and
adding to the amount of impediment produced by friction. In considering the
course and relations of this vessel, it may be conveniently divided into four por-
tions, a cervical, petrous, cavernous, and cerebral.
Cervical Portion. This portion of the internal carotid at its commencement is
very superficial, being contained in the superior carotid triangle, on the same
level but behind the external carotid, overlapped by the Sterno-mastoid, and
covered by the Platysma, deep fascia, and integument; it then passes beneath the
INTERNAL CAROTID.
333
parotid gland, being crossed by the hypo-glossal nerve, the Digastric and Stylo-
hyoid muscles, and the external carotid and occipital arteries. Higher up it is
separated from the external carotid by the Stylo-glossus and Stylo-pharyngeus
muscles and the glosso-pharyngeal nerve. It is in relation, posteriorly, with the
194 — The Internal Carotid and Vertebral Arteries. Eight Side.
UflorUot^^^^^
Rectus anticus major, the superior cervical ganglion of the sympathetic^ and
superior laryngeal nerve; externally, with the internal jugular vein, and pneu-
mogastric nerve; internally, with the pharynx, the tonsil, and the ascending
pharyngeal artery.
334 ARTERIES.
Petrous Portion. When the internal carotid artery enters the canal in the
petrous portion of the temporal bone it first ascends a short distance, then curves
forwards and inwards, and again ascends as it leaves the canal to enter the cavity
of the skull. In this canal, the artery lies at first anterior to the tympanum,
from which it is separated by a thin bony lamella, which is cribriform in the
young subject, and often absorbed in old age. It is separated from the bony wall
of the carotid canal by a prolongation of dura mater, and is surrounded by fila-
ments of the carotid plexus.
Cavernous Portion. The internal carotid artery, in this part of its course,
ascends by the side of the body of the sphenoid bone, being situated on the inner
wall of the cavernous sinus, in relation, externally, with the sixth nerve, and
covered by the lining membrane of the sinus. The third, fourth, and ophthalmic
nerves are placed on the outer wall of the cavernous sinus, being separated from
its cavity by the lining membrane.
Cerebral Portion. On the inner side of the anterior clinoid process the internal
carotid perforates the dura mater, and is received into a sheath of the arachnoid.
This portion of the artery is on the outer side of the optic nerve; it lies at the
inner extremity of the fissure of Sylvius, having the third nerve externally.
Peculiarities. The length of the internal carotid varies according to the length of the
neck, and also according to the point of bifurcation of the common carotid. Its origin
sometimes takes place from the arch of the aorta ; this vessel, in such rare instances, was
placed nearer the middle line of the neck than the external carotid, as far upwards as the
larynx, when the latter vessel crossed the internal carotid. The course of the vessel, in-
stead of being straight, may be very tortuous. A few instances are recorded in which this
vessel may be altogether absent : in one of these the common carotid ascended the neck,
and gave off the usual branches of the external carotid ; the cranial portion of the vessel
being replaced by two branches of the internal maxillary, which entered the skuU through
the foramen rotundum and ovale, and joined to form a single vessel.
Surgical Anatomy. The cervical part of the internal carotid is sometimes wounded by
a stab or gun-shot wound in the neck, or even occasionally by a stab from within the
mouth, as when a person receives a thrust from the end of a pai'asol, or falls down with a
tobacco-pipe in his mouth. In such cases a ligature should be applied to the common
carotid.
The branches given ofi" from the internal carotid are:
From Petrous Portion . Tympanic.
{Arteria receptaculi.
Anterior meningeal.
Ophthalmic.
From Cerebral Portion
( Anterior cerebral.
J Middle cerebral.
I Posterior communicating.
I Anterior choroid.
The Cervical Portion of the internal carotid gives off no branches.
The Tympanic is a small branch which enters the cavity of the tympanum,
through a minute foramen in the carotid canal, and anastomoses with the tym-
panic branch of the internal maxillary, and stylo-mastoid arteries.
The Arteries receptaculi are numerous small vessels, derived from the carotid
artery in the cavernous sinus; they supply the pituitary body, the Casserian
ganglion, and the walls of the cavernous and inferior petrosal sinuses. One of
these branches, distributed to the dura mater, is called the anterior meningeal; it
anastomoses with the middle meningeal.
The Ophthalmic Artery arises from the internal carotid, just as that vessel
is emerging from the cavernous sinus, on the inner side of the anterior clinoid
process, and enters the orbit through the oj)tic foramen, below and on the outer
side, of the optic nerve. It then crosses above, and to the inner side of this
nerve, to the inner wall of the orbit, and, passing horizontally forwards, beneath
the lower border of the Superior oblique muscle, to the inner angle of the eye,
divides into two terminal branches, the frontal, and nasal.
OPHTHALMIC.
335
Branches. The branches of this vessel may be divided into an orbital group,
which are distributed to the orbit and surrounding parts ; and an ocular group,
which supply the muscles and globe of the eye.
195. — The Ophthalmic Artery and its Branches, the Roof of the Orbit having been
removed.
Paljaeliral
A-nitrioT Mhmmi^'X
fost&rioT ^hmoidal-
UfJitl almic
-livtemai CavoticL
Orbital Group.
Lachrymal.
Supra-orbital.
Posterior ethmoidal.
Anterior ethmoidal.
Palpebral.
Frontal.
Nasal.
Ocular Group.
Muscular.
Anterior ciliary.
Short ciliary.
Long ciliary.
Arteria centralis retinse.
The Lachrymal is the first, and one of the largest branches, derived from the
ophthalmic, arising close to the optic foramen, and not unfrequently from that
vessel before entering the orbit. It accompanies the lachrymal nerve along the
upper border of the External rectus muscle, and is distributed to the lachrymal
gland. Its terminal branches, escaping from the gland, are distributed to the
upper eyelid and conjunctiva, anastomosing with the palpebral arteries. The
lachrymal artery gives off one or two malar branches ; one of which passes
through a foramen in the malar bone to reach the temporal fossa and
anastomoses with the deep temporal arteries. The other appears on the cheek,
and anastomoses with the transverse facial. A branch is also sent backwards,
through the sphenoidal fissure, to the dura mater, which anastomoses with a
branch of the middle meningeal artery.
Peculiarities. The lachrymal artery is sometimes derived from one of the anterior
branches of the middle meningeal artery.
The Supra-orbital artery, the largest branch of. the ophthalmic, arises from that
336 AETERIES.
vessel above the optic nerve. Ascending so as to rise above all the muscles of
the orbit, it passes forwards, with the frontal nerve, between the periosteum and
Levator palpebrse ; and, passing through the supra-orbital foramen, divides into a
superficial and deep branch, which supply the muscles and integument of the
forehead and pericranium, anastomosing with the temporal, angular branch of the
facial, and the artery of the opposite side. This artery in the orbit supplies the
Superior rectus and the Levator palpebral, sends a branch inwards, across the
pulley of the Superior oblique muscle, to supply the parts of the inner canthus ;
and at the supra-orbital foramen, frequently transmits a branch to the diploe.
The Ethmoidal branches are two in number ; posterior, and anterior. The
former, which is the smaller, passes through the posterior ethmoidal foramen,
supplies the posterior ethmoidal cells, and, entering the cranium, gives off a
meningeal branch, which supplies the adjacent dura mater, and nasal branches,
which descends into the nose through apertures in the cribriform plate, anasto-
mosing with branches of the spheno-palatine. The anterior ethmoidal artery
accompanies the nasal nerve through the anterior ethmoidal foramen, supplies the
anterior ethmoidal cells, and frontal sinuses, and, entering the cranium, divides
into a meningeal branch, which supplies the adjacent dura mater, and a nasal
branch which descends into the nose, through an aperture in the cribriform
plate.
The Palpebral arteries, two in number, superior and inferior, arise from the
ophthalmic, opposite the pulley of the Superior oblique muscle ; they encircle the
eyelids near their free margin, forming a superior and an inferior arch, which lie
between the Orbicularis muscle and tarsal cartilage. The superior palpebral,
inosculating at the outer angle of the orbit with the orbital branch of the
temporal artery. The inferior branch anastomoses with the orbital branch of the
infra-orbital artery, at the inner side of the lid ; from this anastomosis a branch
passes to the nasal duct, ramifying, in its mucous membrane, as far as the inferior
meatus.
The Frontal artery, one of the terminal branches of the ophthalmic, passes from
the orbit at its inner angle, and, ascending on the forehead, supplies the muscles,
integument, and pericranium, anastomosing with the supra-orbital artery.
The Nasal artery, the other terminal branch of the ophthalmic, emerges from
the orbit above the tendo oculi, and, after giving a branch to the lachrymal sac,
divides into two, one of which anastomoses with the angular artery, the other
branch, the dorsalis nasi, runs along the dorsum of the nose, supplies its entire
surface, and anastomoses with the artery of the opposite side.
The Ciliary arteries are divisible into three groups, the short, long, and
anterior.
The Short Ciliary arteries, from twelve to fifteen in number, arise from the
ophthalmic, or some of its branches ; they surround the optic nerve as they pass
forwards to the posterior part of the eyeball, pierce the sclerotic coat around the
entrance of this nerve, and supply the choroid coat and ciliary processes.
The Long Ciliary arteries, two in number, also pierce the posterior part of the
sclerotic, and run forwards, along each side of the eyeball, between the sclerotic
and choroid, to the ciliary ligament, where they divide into two branches ; these
form an arterial circle around the circumference of the iris, from which numerous
radiating branches pass forwards, in its substance, to its free margin, where they
form a second arterial circle around its pupillary margin.
The Anterior Ciliary arteries are derived from the muscular branches ; they
pierce the sclerotic a short distance from the cornea, and terminate in the great
arterial circle of the iris.
The Arteria Centralis RetincB, is one of the smallest branches of the ophthalmic
artery. It arises near the optic foramen, pierces the optic nerve obliquely, and
runs forvfards, in the centre of its substance, to the retina, in which its branches
are distributed as far forwards as the ciliary processes. In the human foetus, a
OF THE BRAIN.
337
small vessel passes forwards, through the vitreous humour, to the posterior surface
of the capsule of the lens.
The Muscular branches, two in number, superior and inferioi', supply the
muscles of the eyeball. The superior the smaller, often wanting, supplies the
196. — The Arteries at the Base of the Brain. The Right Half of the Cerebellum and Pons
have been removed.
Levator palpebr«, Superior rectus, and Superior oblique. The inferior, more
constant in its existence, passes forwards, between the optic nerve and Inferior
338 ARTERIES.
rectus, and is distributed to the External and Inferior recti, and Inferior oblique.
This vessel gives oif most of the anterior ciliary arteries.
The Cerebral Branches of the internal carotid are, the anterior cerebral, the
middle cerebral, the posterior communicating, and the anterior choroid.
The Anterior Cerebral arises from the internal carotid, at the inner extremity of
the fissure of Sylvius. It passes forwards in the great longitudinal fissure between
the two anterior lobes of the brain, being connected soon after its origin with the
vessel of the opposite side by a short anastomosing trunk, about two lines in length,
the anterior communicating. The two anterior cerebral arteries, lying side by side,
curve around the anterior border of the corpus callosum, and run along its upper
surface to its posterior part, where they terminate by anastomosing with the
the posterior cerebral arteries. They supply the olfactory and optic nerves, the
under surface of the anterior lobes, the third ventricle, the anterior perforated
space, the corpus callosum, and the inner surface of the hemispheres.
The Anterior communicating Artery is a short branch, about two lines in length,
but of moderate size, connecting together the two anterior cerebral arteries across
the longitudinal fissure. Sometimes this vessel is wanting, the two arteries joining
together to form a single trunk, which afterwards subdivides. Or the vessel may
be wholly or partially subdivided into two; frequently, it is longer and smaller
than usual.
The Middle Cerebral Artery, the largest branch of the internal carotid, passes
obliquely outwards along the fissure of Sylvius, within which it divides into three
branches: an anterior, which supplies the pia mater, investing the surface of the
anterior lobe; a posterior, which supplies the middle lobe; and a median branch,
which supplies the small lobe at the outer extremity of the Sylvian fissure. Near
its origin, this vessel gives off numerous small branches, which enter the substantia
perforata, to be distributed to the corpus striatum.
The Posterior communicating Artery arises from the back part of the internal
carotid, runs directly backwards, and anastomoses with the posterior cerebral, a
branch of the basilar. This artery varies considerably in size, being sometimes
small, and occasionally so large that the posterior cerebral may be considered as
arising from the internal carotid rather than from the basilar. It is frequently
larger on one than on the other side.
The Anterior Choroid is a small but constant branch which arises from the
back part of the internal carotid, near the posterior communicating artery.
Passing backwards and outwards, it enters the descending horn of the lateral ven-
tricle, beneath the edge of the middle lobe of the brain. It is distributed to the
hippocampus major, corpus fimbriatum, and choroid plexus.
ARTERIES OF THE UPPER EXTREMITY.
The artery which supplies the upper extremity, continues as a single trunk from
its commencement, as far as the elbow; but different portions of it have received
different names, according to the region through which it passes. Thus, that
part of the vessel which extends from its origin, as far as the outer border of
the first rib, is termed the subclavian; beyond this point to the lower border of
the axilla, it is termed the axillary; and from the lower margin of the axillary
space to the bend of the elbow, it is termed brachial; here, the single trunk
terminates by dividing into two branches, the radial, and ulnar, an arrangement
precisely similar to what occurs in the lower limb.
Subclavian Arteries.
The subclavian artery on the right side arises from the arteria innominata,
opposite the right sterno-clavicular articulation ; on the left side, it arises from the
arch of the aorta. It follows, therefore, that these two vessels must, in the first
part of their course, difier in their length, their direction, and in their relation
with neighboiu'ing parts.
SUBCLAVIAN.
339
In order to facilitate the description of these vessels, more especially in a sur-
gical point of view, each subclavian arteiy has been divided into three parts.
The first portion, on the right side, ascends obliquely outwards, from the origin of
the vessel to the inner border of the Scalenus anticus. On the left side, it ascends
perpendicularly to the inner border of this muscle. The second part passes out-
wards, behind the Scalenus anticus; and the third part passes from the outer mar-
gin of this muscle, beneath the clavicle, to the lower border of the first rib, where
it becomes the axillary artery. The first portions of these two vessels differ so
much in their course, and in their relation with neighbouring parts, that they will
be described separately. The second and third parts are precisely alike on both
sides.
First Part of the Right SuBCLAvivm Artery (figs. i88, 189).
It arises from the arteria innominata, opposite the right sterno-clavicular arti-
culation, passes upwards and outwards across the root of the neck, and terminates
at the inner margin of the Scalenus anticus muscle. In this part of its course, it
ascends a little above the clavicle, the extent to which it does so varying in differ-
ent cases. It is covered, in front, by the integument, superficial and deep fascige,
Platysma, the clavicular origin of the Sterno-mastoid, the Sterno-hyoid and Sterno-
thyroid muscles, and another layer of the deep fascia. It is crossed by the internal
jugular and vertebral veins, and by the pneumogastric, the cardiac branches of
the sympathetic, and phrenic nerves. Beneath, the artery is invested by the
pleura, and behind, it is separated by a cellular interval from the Longus colli,
the transverse process of the seventh cervical vertebra, and the sympathetic; the
recurrent laryngeal nerve winding around the lower and back part of this vessel.
The subclavian vein lies below the subclavian artery, immediately behind the
clavicle.
Plan of Relations of First Portion of Right Subclavian Artery.
In front.
Integument, superficial and deep fasciae.
Platysma.
Clavicular origin of Sterno-mastoid.
Sterno-hyoid and Sterno-thyroid.
Internal jugular and vertebral veins.
Pneumogastric, cardiac, and phrenic nerves.
Right
Subclavian \ Beneath.
Artery. j Pleura.
i^First portion-
Behind.
Recurrent laryngeal nerve.
Sympathetic.
Longus colli.
Transverse process of seventh cervical vertebra.
First Part of the Left Subclavian Artery (fig. 187).
It arises from the end of the transverse portion of the arch of the aorta, oppo-
site the second dorsal vertebra, and ascends to the inner margin of the first rib,
behind the insertion of the Scalenus anticus muscle. This vessel is, therefore,
longer than the right, situated more deeply in the cavity of the chest, and
directed almost vertically upwards, instead of arching outwards like the vessel of
the opposite side.
It is in relation, in front, with the pleura, the left lung, the pneumogastric,
phrenic, and cardiac nerves, which lie parallel with it, the left carotid artery, left
internal jugular and innominate veins, and is covered by the Sterno-thyroid, Sterno-
z 2
340 ARTEEIES.
hyoid, and Sterno-mastoid muscles; behind, with the cESophagus, thoracic duct,
inferior cervical ganglion of the sympathetic, Longus colli, and vertebral column.
To its inner side is the oesophagus, trachea, and thoracic duct; to its outer side,
the pleura.
Plan of Relations of First Portion of Left Subclavian Artery.
Infront.
Pleura and left lung.
Pneumogastric, cardiac, and phrenic nerves.
Left carotid artery.
Left internal jugular and innominate veins.
Sterno-thyroid, Sterno-hyoid, and Sterno-mastoid muscles.
Inner side. f -'-'^" \ Outer side.
CEsophagus. / Subclavian \ Pleura.
Trachea I Artery.
Thoracic duct. \^i''st Po^'ion.
Behind.
CEsophagus and thoracic duct.
Inferior cervical ganglion of sympathetic.
Longus coUi and vertebral column.
The relations of the second and third portions of the subclavian arteries are
precisely similar on both sides.
The Second Portion of the Subclavian Artery lies between the two Scaleni
muscles; it is very short, and forms the highest part of the arch described by
that vessel.
Relations. It is covered, m yrowif, by the integument, Platysma, Sterno-mastoid,
cervical fascia, and by the phrenic nerve, which is separated from the artery by
the Scalenus anticus muscle. Behind, it is in relation with the Middle scalenus.
Above, with the brachial plexus of nerves. Below, with the pleura. The
subclavian vein lies below the artery, separated from it by the Scalenus anticus.
Plan of the Relations of the Second Portion op the Subclavian Artery.
Infront.
Platysma and Sterno-mastoid. Phrenic nerve.
Cervical fascia. Scalenus anticus.
Above. I Aiterj. | Below.
Brachial plexus. ISecond portion/ Pleura.
Beiimd.
Middle scalenus.
The Third Portion of the Subclavian Artery passes downwards and outwards
from the outer margin of tlae Scalenus anticus to the lower border of the first
rib, where it becomes the axillary artery. This portion of the vessel is the most
superficial, and is contained in a triangular space, the base of which is formed in
front by the Anterior scalenus, and the two sides by the Omo-hyoid above and the
clavicle below.
Relations. It is covered, infront, by the integument, the superficial and deep
fascife, the Platysma; and by the clavicle, the Subclavius muscle, and the supra-
scapular artery and vein below; the clavicular descending branches of the cervical
plexus and the nerve to the Subclavius pass vertically downwards in front of the
artery. The external jugular vein crosses it at its inner side, and receives the
supra- scapular and transverse cervical veins, which occasionally form a plexus in
front of it. The subclavian vein is below the artery, lying close behind the
SUBCLAVIAN. 341
clavicle. Behind, it lies on the Middle scalenus muscle. Above it, and to its
outer side, is the brachial plexus, and Omo-hyoid muscle. Below, it rests on the
outer surface of the first rib.
Plan of the Relations of the Third Portion of the Subclavian Artery.
In front.
Integument, fasciee, and Platysma.
The external jugular, supra-scapular, and transverse cervical veins.
Descending branches of cervical plexus.
Subclavius muscle, supra-scapular vessels, and clavicle.
^ ,^.^f ^- / Subclavian ,
Brachial plexus. / Arterv I Below.
Omo-hyoid. ^Third portion-/ First rib.
Behind.
Scalenus medius.
Peculiarities. The subclavian arteries vary in their origin, their course, and in the height
to which they rise in the neck.
The origin of the right subclavian from the innominate takes place, in some cases, above
the sterno-clavicular articulation ; more frequently in the cavity of the thorax, below that
joint. Or the artery may arise as a separate trunk from the arch of the aorta ; in such
cases it may be either the first, second, third, or even the last branch derived from that
vessel: in the majority of cases, it is the first or last, rarely the second or third.
When it is the first branch, it occupies the ordinary position of the innominate artery ;
when the second or third, it gains its usual position by passing behind the right carotid ;
and when the last branch, it arises from the left extremity of the arch, at its upper or
back part, and passes obliquely towards the right side, behind the oesophagus and right
carotid, sometimes between the ossophagus and trachea, to the upper border of the first
rib, where it follows its ordinary course. In very rare instances, this vessel arises from the
thoracic aorta, as low down as the fourth dorsal vertebra. Occasionally it perforates the
Anterior scalenus ; more rarely it passes in front of this muscle : sometimes the subclavian
vein passes with the artery behind the Scalenus. The artery sometimes ascends as high
as an inch and a half above the clavicle, or to any intermediate point between this and the
upper border of this bone, the right subclavian usually ascending higher than the left.
The left subclavian is occasionally joined at its origin with the left carotid.
Surgical Anatomy. The relations of the subclavian arteries of the two sides having been
examined, the student should direct his attention to consider the best position in which
compression of the vessel may be effected, or in what situation a ligature may be best
applied in cases of aneuiism or wounds.
Compression of the subclavian artery is required in cases of operations about the shoulder,
in the axilla, or at the upper part of the arm ; and the student will observe that there is
only one situation in which it can be effectually applied, viz., where the artery passes
across the outer surface of the fii'st rib. In order to compress the vessel in this situation,
the shoulder should be depressed, and the surgeon, grasping the side of the neck, may press
with his thumb in the hollow behind the clavicle downwards against the rib ; if from any
cause the shoulder cannot be sufficiently depressed, pressure may be made from before
backwards, so as to compress the artery against the Middle scalenus and transverse pi'ocess
of the seventh cervical vertebra.
Ligature of the subclavian artery may be required in cases of wounds of the axillary
artery, or in aneurism of that vessel ; and the third part of the artery is consequently that
which is most favourable for such an operation, on account of its being comparatively
superficial, and most remote from the oi'igin of the large branches. In those cases where
the clavicle is not displaced, this operation may be performed with comparative facility ;
but whei'e the clavicle is elevated from the presence of a large aneurismal tumour in the
axilla, the artery is placed at a great depth from the surface, which materially Id creases
the difficulty of the operation. Under these circumstances, it becomes a matter of impor-
tance to consider the height to which this vessel reaches above the bone. In ordinary
cases its arch is about half an inch above the clavicle, occasionally as high as an inch and
a half, and sometimes bo low as to be on a level with its upper border. If displacement
of the clavicle occurs, these variations will necessarily make the operation more or less
difficult, according as the vessel is more or less accessible.
The chief points in the operation of tying the third portion of the subclavian artery are
as follows. The patient being placed on a table in the horizontal position, and the shoulder
depressed as much as possible, the integument should be -di-awn downwards upon the
clavicle and an incision made through it upon that bone .from the anterior border of
342
ARTERIES.
the Trapezius to the posterior border of the Sterno-mastoid, to which may be added a short
vertical incision meeting the centre of the preceding ; the Platysma myoides and cervical
fascia should be divided u^Don a director, and if the interval between the Trapezius and
Sterno-mastoid muscles be insufficient for the performance of the operation, a portion of one
or both may be divided. The external jugular vein will now be seen towards the inner side
of the wound ; this and the scapular and transverse cervical veins which terminate in it
should be held aside, and if divided both ends should be included in a ligature : the supra-
scapular artery should be avoided, and the Omo-hyoid muscle must now be looked for, and
held aside if necessary. In the space beneath this muscle, careful search must be made
for the vessel ; the deep fascia having been divided with the finger-nail or silver scalpel,
the outer margin of the Scalenus muscle must be felt for, and the finger being guided by
it to the first rib, the pulsation of the subclavian artery will be felt as it passes over its
surface. The aneurism needle may then be passed around the vessel from before backwards,
by which means the vein will be avoided, care being taken not to include a branch of the
brachial plexus instead of the artery in the ligature. If the clavicle is so raised by the
tumour that the application of the ligature cannot be eflected in this situation, the artery
may be tied above the first rib, or even behind the Scalenus muscle : the difficulties of
the operation in such a case will be materially increased, on account of the greater depth
of the artery, and alteration of the position of the surrounding parts.
The second division of the subclavian artery, from being that portion which rises highest
in the neck, has been considered favourable for the application of the ligatuie, where it is
difficult to apply it in the third part of its course. There are, however, many objections
to the operation in this situation. It is necessary to divide the Scalenus anticus muscle,
upon which lies the phrenic nerve, and at the inner side of which is situated the internal
jugular vein ; a wound of either of these structures might lead to the most dangerous con-
sequences. Again, the artery is in contact, below, with the pleura, which must also be
avoided ; and lastly, the proximity of so many of its larger branches arising internal to this
point, must be a still further objection to the operation. If, however, it has been deter-
mined upon to perform the operation in this situation, it should be remembered that it
occasionally happens that the artery passes in front of the Scalenus anticus, or through the
fibres of that muscle ; or that the vein sometimes passes with the artery behind the Sca-
lenus anticus.
In those cases of aneurism of the axillary or subclavian artery which encroach upon the
outer portion of the Scalenus muscle to such an extent that a ligature cannot be applied
in that situation, it may be deemed advisable, as a last resource, to tie the first portion of
the subclavian artery. On the left side this operation is quite impracticable, the great
depth of the artery from the surface, its intimate relation with the pleura, and its close
proximity with so many important veins and nerves, present a series of difficulties which
it is impossible to overcome. On the right side the operation is practicable, and has been
performed, though not with success. The main objection to the operation in this situation
is the smallness of the interval which usually exists between the commencement of the
vessel and the origin of the nearest branch. This operation may be performed in the fol-
lowing manner. The patient being placed on a table in the horizontal position, with the
neck extended, an incision should be made parallel with the inner part of the clavicle, and a
second along the inner border of the Sterno-mastoid, meeting it at right angles. The
sternal attachment of the Sterno-mastoid may now be divided on a director, and turned
outwards ; a fev7 small arteries and veins, and occasionally the anterior jugular must be
avoided, and the Sterno-hyoid and thyroid muscles divided in the same manner as the pre-
ceding muscle. After tearing through the deep fascia with the finger-nail, the internal
jugular vein will be seen crossing the artery ; this should be pressed aside, and the artery
secured by passing the needle from below upwards, by which the pleura is more efi"ectually
avoided. The exact position of the vagus nerve, the recurrent laryngeal, the phrenic and
sympathetic nerves, should be remembered, and the ligature should be applied near the
origin of the vertebral, in order to afford as much room as possible for the formation of a
coagulum between the ligature and the origin of the vessel. It should be remembered that
the right subclavian artery is occasionally deeply placed in the first part of its course, when
it arises from the left side of the aortic arch, and passes in such cases behind the cesopha-
gus, or between it and the trachea.
Branches of the Subclavian Artery (fig. 197).
These are four in number. Three arising from the first portion of the vessel,
the vertebral, the internal mammary, and the thyroid axis; and one from the second
portion, the superior intercostal. The vertebral arises from the upper and back
part of the first portion of the artery; the thyroid axis from the front, and the
internal mammary from the under part of this vessel. The superior intercostal is
given off from the upper and back part of the second portion of the artery. On
the left side the second portion usually gives off no branch, the superior intercostal
arising to the inner side of the Scalenus anticus. On both sides of the body, the
VERTEBRAL.
343
197.
-Plan of the Branches of the Right
Subclavian Artery.
first three branches arise close together at the inner margin of the Scalenus anticus
in the majority of cases a free interval of half an inch to an inch existing between
the commencement of the artery and the
origin of the nearest branch; in a smaller
number of cases, an interval of more than
an inch existed, never exceeding an inch
and three-quarters. In a very few in-
stances the interval was less than half
an inch.
Vertebral, Artery (fig. 194).
The vertebral artery is generally the
first and largest branch of the subclavian ;
it arises from the upper and back part of
the first portion of the vessel, and passing
upwards, enters the foramen in the trans-
verse process of the sixth cervical verte-
bra, and ascends through the foramina in
the transverse processes of all the ver-
tebrae. Above the upper border of the axis, it inclines outwards and upwards to
the foramen in the transverse process of the atlas, through which it passes; it then
winds backwards behind its articular process, runs in a deep groove on the surface
of the posterior arch of this bone, and piercing the posterior occipito-atloid liga-
ment and dura mater, enters the skull through the foramen magnum. It then
passes in front of the medulla oblongata, and unites with the vessel of the opposite
side at the lower border of the pons Varolii, to form the basilar artery.
At its origin, it is situated behind the internal jugular vein and inferior thyroid
artery, and, near the spine, lies between the Longus colli and Scalenus anticus
muscles, having the thoracic duct in front of it on the left side. Within the fora-
mina formed by the transverse processes of the vertebrae, it is accompanied by a
plexus of nerves from the sympathetic, and lies between the vertebral vein, which
is in front, and the cervical nerves, which issue from the intervertebral foramina
behind it. Whilst winding around the articular process of the atlas, it is con-
tained in a triangular space formed by the Rectus posticus minor, the Superior and
Inferior oblique muscles; and is covered by the Rectus posticus major and Com-
plexus. And within the skull, as it winds around the medulla oblongata, it is
placed between the hypoglossal and anterior root of the sub-occipital nerves.
Branches. These may be divided into two sets, those given off in the neck, and
those within the cranium.
Cervical Branches
Cranial Branches.
■{
Lateral spinal.
Muscular.
Posterior meningeal.
Anterior spinal.
Posterior spinal.
Inferior cerebellar.
The Lateral Spi^ial Branches enter the spinal canal through the inter- vertebral
foramina, each dividing into two branches. Of these, one passes along the roots
of the nerves to supply the spinal cord and its membranes anastomosing with the
other spinal arteries ; the other is distributed to the posterior surface of the bodies
of the vertebrse.
, Several large Muscular Branches are given ofi" to the deep muscles of the neck
where the vertebral arteiy curves around the articular process of the atlas. They
anastomose with the occipital and deep cervical arteries.
The Posterior Meningeal are one or two small branches given ofi" from the ver-
tebral opposite the foramen magnum. They ramify- between the bone and dura
mater in the cerebellar foss«, and supply the falx cerebelli.
344 ARTERIES.
The Anterior Spinal is a small branch, larger than the posterior spinal, which
arises near the tei'mination of the vertebral, and unites with its fellow of the op-
posite side in front of the medulla oblongata. The single trunk thus formed,
descends a short distance on the anterior aspect of the spinal cord, and joins with
a succession of small branches which enter the spinal canal through some of the
inter- vertebral foramina; these branches are derived from the vertebral and
ascending cervical, in the neck; from the intercostal, in the dorsal region; and
from the lumbar, ilio-lumbar, and lateral sacral arteries in the lower part of the
spine. They unite, by means of ascending and descending branches, to form a
single anterior median artery, which extends as low down as the lower part of the
spinal cord. This vessel is placed beneath the pia mater along the anterior median
fissure, it supplies that membrane and the substance of the cord, and sends off
branches at its lower part to be distributed to the Cauda equina.
The Posterior Spinal arises from the vertebral, at the side of the medulla
oblongata, passing backwards to the posterior aspect of the spinal cord, it
descends on either side, lying behind the posterior roots of the spinal nerves, and
is reinforced by a succession of small branches, which enter the spinal canal
through the intervertebral foramina, and by which it is continued to the lower
part of the cord, and to the Cauda equina. Branches from these vessels form a
free anastomosis around the posterior roots of the spinal nerves, and communicate,
by means of very tortuous transverse branches, with the vessel of the opposite
side. At its commencement, it gives off an ascending branch, which terminates
on the sides of the fourth ventricle.
The Inferior Cerebellar artery, the largest branch of the vertebral, winds back-
wards around the upper part of the medulla oblongata, passing between the origin
of the spinal accessory and pneumogastric nerves, over the restiform body, to the
under surface of the cerebellum, where it divides' into two branches ; an internal
one, which is continued backwards to the notch between the two hemispheres of
the cerebellum ; and an external one, which supplies the under surface of the
cerebellum, as far as its outer border, where it anastomoses with the superior
cerebellar. Branches from this artery supply the choroid plexus of the fourth
ventricle.
The Basilar artery, so named from its position at the base of the skull, is a
single trunk, formed by the junction of the two vertebral arteries ; it extends
from the posterior to the anterior border of the pons Varolii, where it divides into
two terminal branches, the posterior cerebral arteries. Its branches are, on each
side, the following :
Transverse. Superior cerebellar.
Anterior cerebellar. Posterior cerebral.
The Transverse branches supply the pons Varolii and adjacent parts of the
brain ; one accompanies the auditory nerve into the internal auditory meatus ; and
another, of larger size, passes along the crus cerebelli, to be distributed to the
anterior border of the under surface of the cerebellum. It is called the anterior
{inferior) cerebellar artery.
The Superior Cerebellar arteries arise near the termination of the basilar.
They wind round the crus cerebri, close to the fourth nerve, and, arriving at the
upper surface of the cerebellum, divide into branches which supply the pia mater,
covering its surface, anastomosing with the inferior cerebellar. It gives several
branches to the pineal gland, and also to the velum interpositum.
The Posterior Cerebral arteries, the two terminal branches of the basilar, are
larger than the preceding, from which they are separated near their origin by the
third nerves. Winding around the crus cerebri, they pass to the under surface of
the posterior lobes of the cerebrum, which they supply, anastomosing with the
anterior and middle cerebral arteries. Near their origin they give off a number
of parallel branches, which enter the posterior perforated spot, and receive the
posterior communicating arteries from the internal carotid. They also give off a
INFERIOR THYROID, SUPRA- SCAPULAR. 345
branch, the posterior choroid, which supplies the velum interpositum and choroid
plexus, entering the interior of the brain, beneath the posterior border of the
corpus callosum.
Circle of Willis. The remarkable anastomosis which exists between the
branches of the internal carotid, and vertebral arteries at the base of the brain,
constitutes the circle of Willis. It is formed, in front, by the anterior cerebral
and anterior communicating arteries ; on each side, by the trunk of the internal
carotid, and the posterior communicating ; behind, by the posterior cerebral, and
point of the basilar. It is by this anastomosis that the cerebral circulation is
equalized, and provision made for effectually carrying it on if one or more of the
branches are obliterated. The parts of the brain included within this arterial
circle are, the lamina cinerea, the commissure of the optic nerves, the infundi-
bulum, the tuber cinereum, the corpora albicantia, and the pars perforata postica.
Thyroid Axis.
The thyroid axis is a short, thick trunk, which arises from the fore part of
the first portion of the subclavian artery, close to the inner side of the Scalenus
anticus muscle, and divides, almost immediately after its origin, into three
branches, the inferior thyroid, supra-scapular, and transversalis colli.
The Inferior Thyroid Artery passes upwards, in a serpentine course, behind
the sheath of the carotid vessel and sympathetic nerve, the middle cervical
ganglion resting upon this vessel, and is distributed to the under surface of the
thyroid gland, anastomosing with the superior thyroid, and with the corre-
sponding artery of the opposite side. Its branches are the
Laryngeal. CEsophageal.
Tracheal. Ascending cervical.
The Laryngeal branch ascends upon the trachea to the back part ol the
larynx, and supplies the muscles and the mucous membrane of this part.
The Tracheal branches are distributed over the trachea, anastomosing below
with the bronchial arteries.
The (Esophageal branches are distributed to the oesophagus.
The Ascending cervical artery is a small branch which arises from the inferior
thyroid, just where that vessel is passing behind the carotid artery, and runs up
the neck in the interval between the Scalenus anticus, and Rectus anticus major.
It gives branches to the muscles of the neck, which communicate with those sent
out from the vertebral, and sends one or two through the intervertebral foramina,
along the cervical nerves, to supply the bodies of the vertebrae, the spinal cord,
and its membranes.
The Supra- Scapular Artery, smaller than the transverse cervical, passes
obliquely from within outwards, across the root of the neck. It at first lies on
the lower part of the Scalenus anticus, being covered by the Sterno-mastoid ; it
then crosses the subclavian artery, and runs outwards behind, and parallel with,
the clavicle and Subclavius muscle, and beneath the posterior belly of the Omo-
hyoid, to the superior border of the scapula, where it passes over the ligament of
the supra-scapular notch to the supra-spinous fossa. In this situation it lies close
to the bone, and ramifies between it and the Supra-spinatus muscle to which it is
mainly distributed, giving off a communicating branch, which crosses the neck of
the scapula, to reach the infra-spinous fossa, where it anastomoses with the dorsal
branch of the subscapular artery. Besides distributing branches to the Sterno-
mastoid, and neighbouring muscles, it gives off a supra-acromial branch, which,
piercing the Trapezius muscle, supplies the cutaneous surface of the acromion,
anastomosing with the acromial thoracic artery. As the artery passes across the
supra-scapular notch, a branch descends into the subscapular fossa, ramifies
beneath that muscle, and anastomoses with the posterior and subscapular arteries.
It also supplies the shoulder joint.
346
ARTERIES.
The Transversalis Colli passes transversely outwards, across the upper part
of the subclavian triangle, to the anterior margin of the Trapezius muscle, beneath
/7\
i88.. — The Scapular and Circumflex Arteries.
EoJslerioT Scafiular
which it divides into two branches, the superficial cervical, and the posterior
scapular. In its course across the neck, it passes in front of the Scaleni muscles
and the brachial plexus, between the divisions of which it sometimes passes, and
is covered in by the Platysma, Sterno-mastoid, Omo-hyoid, and Trapezius
muscles.
The Superficial Cervical ascends beneath the anterior margin of the Tra-
pezius, distributing branches to it, and to the neighbouring muscles and glands in
the neck.
The Posterior Scapular, the continuation of the transverse cervical, passes
beneath the levator anguli scapulse to the superior angle of the scapula, and
descends along the posterior border of that bone as far as the inferior angle,
where it anastomoses with the subscapular branch of the axillary. In its course
it is covered in by the Rhomboid muscles, supplying these, the Latissimus dorsi
and Trapezius, and anastomoses with the supra-scapular and subscapular
arteries, and with the posterior branches of some of the intercostal arteries.
Peculiarities. The Superficial Cervical frequently arises as a separate branch from the
thyroid axis ; and the posterior scapular, from the third, more rarely from the second,
part of the subclavian.
The Internal Mammary arises from the under surface of the first portion of
the subclavian artery, opposite the thyroid axis. It descends behind the clavicle,
to the inner surface of the anterior wall of the chest, resting upon the costal
cartilages, a short distance from the margin of the sternum; and, at the interval
between the sixth and seventh cartilages, divides into two branches, the musculo-
phrenic, and superior epigastric.
At its origin, it is covered by the internal jugular and subclavian veins, and
crossed by the phrenic nerve. In the upper part of the thorax, it lies upon the
costal cartilages, and internal Intercostal muscles in front, covered by the pleura
behind. At the lower part of the thorax, the Triangularis sterni separates this
vessel from the pleura. It is accompanied by two veins, which join at the upper
part of the thorax into a single trunk.
INTERNAL MAMMARY, SUPERIOR INTERCOSTAL. 347
The branches of the internal mammary are,
Comes nervi phrenici (superior phrenic). Anterior intercostal.
Mediastinal. Perforating.
Pericardiac. Musculo-phrenic.
Sternal. Superior epigastric.
The Comes Nervi Phrenici (^Superior Phrenic), is a long slender branch, which
accompanies the phrenic nerve, between the pleura and pericardium, to the Dia-
phragm, to which it is distributed; anastomosing with the other phrenic arteries
from the internal mammary, and abdominal aorta.
The Mediastinal Branches are small vessels, which are distributed to the areolar
tissue in the anterior mediastinum, and the remains of the thymus gland.
The Pericardiac Branches supply the upper part of the pericardium, the lower
part receiving branches from the musculo-phrenic artery. Some sternal branches
are distributed to the Triangularis sterni, and both surfaces of the sternum.
The Anterior Intercostal Arteries supply the five or six upper intercostal spaces.
The branch corresponding to each space passes outwards, and soon divides into
two, which run along the opposite edges of the ribs, and inosculate with the inter-
costal arteries from the aorta. They are at first situated between the pleura and
the internal Intercostal muscles, and then between the two layers of these muscles.
They supply the Intercostal and Pectoral muscles, and the mammary gland.
The Anterior or Perforating Arteries correspond to the five or six upper inter-
costal spaces. They arise from the internal mammary, pass forwards through the
intercostal spaces, and, curving outwards, supply the Pectoralis major, and the in-
tegument. Those which correspond to the first three spaces, are distributed to
the mammary gland. In females, during lactation, these branches are of large
size.
The Musculo-phrenic Artery is directed obliquely downwards and outwards,
behind the cartilages of the false ribs, perforating the Diaphragm at the eighth or
ninth rib, and terminating, considerably reduced in size, opposite the last inter-
costal space. It gives off anterior intercostal arteries to each of the intercostal
spaces across which it passes; they diminish in size as the spaces decrease in length,
and are distributed in a manner precisely similar to the anterior intercostals from
the internal mammary. It also gives branches backwards to the Diaphragm, and
downwards to the abdominal muscles.
The Superior Epigastric continues in the original direction of the internal
mammary, descends behind the Rectus muscle, and, perforating its sheath, divides
into branches which supply the Rectus, anastomosing with the epigastric artery
from the external iliac. Some vessels perforate the sheath of the Rectus, and
supply the muscles of the abdomen and the integument, and a small branch which
passes inwards upon the side of the ensiform appendix, anastomoses in front of
that cartilage with the artery of the opposite side.
The Superior Intercostal arises from the upper and back part of the second
portion of the subclavian artery on the right side, and to the inner side of the
Scalenus anticus on the left side. Passing backwards, it gives off the deep cer-
vical branch, and descends behind the pleura in front of the necks of the first two
ribs, and inosculates with the first aortic intercostal. In the first intercostal space,
it gives off a branch which is distributed in a similar manner with the aortic in-
tercostals. The branch for the second intercostal space usually joins with one
from the first aortic intercostal. Each intercostal gives off a branch to the posterior
Spinal muscles, and a small one, which passes through the corresponding inter-
vertebral foramen to the spinal cord and its membranes.
The Deep Cervical Branch {Profunda Cervicis) arises, in most cases, from
the superior intercostal, and is analogous to the posterior branch of an aortic in-
tercostal artery. Passing backwards, between tlie transverse process of the seventh
cervical vertebra and the first rib, it ascends the back part of the neck, between
the Complexus and Semi-spinalis colli muscles, as high as the axis, supplying these
348
SURGICAL ANATOMY
and adjacent muscles, and anastomosing with tlie arteria princeps cervicis of the
occipital, and with branches which pass outwards from the vertebral.
Surgical Anatomy of the Axilla.
The Axilla is a conical space, situated between the upper and lateral parts of
the chest, and inner side of the arm.
Boundaries. Its apex, which is directed upwards towards the root of the neck,
corresponds to the interval between the first rib internally, the superior border of
the scapula externally, and the clavicle and Subclavius muscle in front. The base,
directed downwards, is formed by the integument, and a thick layer of fascia, ex-
tending between the lower border of the Pectoi'alis major in front, and the lower
199. — The Axillary Artery, and its Branches.
border of the Latissimus dorsi behind; it is broad internally, at tne chest, but
narrow and pointed externally, at the arm. Its anterior boundary is formed by
the Pectoralis major and Minor muscles, the former covering in the whole of the
anterior wall of the axilla, the latter covering only its central part. Its posterior
boundary, which extends somewhat lower than the anterior, is formed by the Sub-
scapularis above, the Teres major and Latissimus dorsi below. On the inner side
are the first four ribs and their corresponding Intercostal muscles, and part of the
Serratus magnus. On the outer side, where the anterior and posterior boundaries
converge, the space is narrow, and bounded by the humerus, the Coraco-brachialis
and Biceps muscles.
^ Conterits. This space contains the axillary vessels, and brachial plexus of nerves
with their branches, some branches of the intercostal nerves, a large number of
lymphatic glands, all connected together by a quantity of fat and loose areolar
tissue.
OF THE AXILLA.
349
Their Position. The axillary artery and vein, with the brachial plexus of nerves,
extend obliquely along the outer boundary of the axillary space, from its apex to
its base, and are placed much nearer the anterior than the posterior wall, the vein
lying to the inner or thoracic side of the artery, and altogether concealing it. At
the fore part of the axillary space, in contact with the Pectoral muscles, are the
thoracic branches of the axillary artery, and along the anterior margin of the
axilla, the long thoracic artery extends to the side of the chest. At the back part,
in contact with the lower margin of the Subscapularis muscle, are the subscapular
vessels and nerves; winding around the lower border of this muscle, is the dor-
salis scapulfe artery and veins; and towards the outer extremity of the muscle, the
posterior circumflex vessels and nerve are seen curving backwards to the
shoulder.
Along the inner or thoracic side, no vessel of any importance exists, its upper
part being crossed by a few small branches from the superior thoracic artery.
There are some important nerves, however, in this situation ; the posterior thoracic
or external respiratory nerve, descending on the surface of the Serratus magnus, to
which it is distributed; and perforating the upper and anterior part of this wall,
are the intercosto-humeral nerves, which pass across the axilla to the inner side
of the arm.
The cavity of the axilla is filled by a quantity of loose areolar tissue, a large
number of small arteries and veins, all of which are, however, of inconsiderable
size, and numerous lymphatic glands; these are from ten to twelve in number,
and situated chiefly on the thoracic side, and lower and back part of this
space.
The student should attentively consider the relation of the vessels and nerves in
the several parts of the axilla; for it not unfrequently happens that the stirgeon
is called upon to extirpate diseased glands, or to remove a tumour from this
situation. In performing such an operation, it will be necessary to proceed with
much caution in the direction of the outer wall and apex of the space, as here the
axillary vessels will be in danger of being wounded. Towards the posterior wall,
it will be necessary to avoid the subscapular, dorsalis scapulae, and posterior
circumflex vessels, and, along the anterior wall, the thoracic branches. It is only
along the inner or thoracic wall, and in the centre of the axillary cavity, that
there are no vessels of any importance; a most fortunate circumstance, for it is in
this situation more especially that tumours requiring removal, are most frequently
situated.
The Axillaet Aetert.
The axillary artery, the continuation of the subclavian, commences at the
lower border of the first rib, and terminates at the lower border of the tendons of
the Latissimus dorsi and Teres major muscles, when it becomes the brachial.
Its direction varies with the position of the limb : where the arm lies by the side
of the chest, the vessel forms a gentle curve, the convexity being upwards and
outwards ; when it is directed at right angles with the trunk, the vessel is nearly
straight ; and if elevated still higher, it describes a curve, the concavity of which
is directed upwards. At its commencement the artery is very deeply situated,
but near its termination is superficial, being covered only by the skin and fascia.
The description of the relations of this vessel may be facilitated by its division
into three portions. The first portion being that above the Pectoralis minor ; the
second portion, beneath ; and the third, below that muscle.
The Jirst portion of the axillary artery is in relation, in front, with the
clavicular portion of the Pectoralis major, the costo-coracoid membrane, and the
cephalic vein; behind, with the first intercostal space, the corresponding Inter-
costal muscle, the first serration of the Serratus magnus, and the posterior
thoracic nerve ; on its outer side with the brachial plexus, from which it is
separated by a little cellular interval; on \t&- inner ^ or thoracic side, with the
axillary vein.
350 ARTERIES.
Relations of First Portion of the Axillary Artery.
In front.
Pectoralis major.
Costo-coracoid membrane.
Cephalic vein.
Axillary
Outer side. { Artery. ) Inner side.
Brachial plexus. \ First portion. / Axillary vein.
Behind.
First intercostal space, and Intercostal muscle.
First serration of Serratus magnus.
Posterior thoracic nerve.
The second portion of the axillary artery lies beneath the Pectoralis minor. It
is covered, in front, by the Pectoralis major and minor muscles ; behind, it is
separated from the Subscapularis by a cellular interval ; on the inner side, it is
in contact v^^ith the axillary vein. The brachial plexus of nerves surrounds the
artery, and separates it from direct contact w^ith the vein and adjacent muscles.
'^ Relations of Second Portion of the Axillary Artery.
In front.
Pectoralis major and minor.
Axillary
Outer side. I Artery. \ Inner side.
Brachial plexus. iSecond portion.) Axillary vein.
Behind.
Subscapularis.
The third portion of the axillary artery lies below the Pectoralis minor. It is
in relation, in front, -with, the lower border of the Pectoralis major above, being
covered only by the integument and fascia below ; behind, with the lower part of
the Subscapularis, and the tendons of the Latissimus dorsi and Teres major ; on
its outer side, with the Coraco-brachialis ; on its inner, or thoracic side, with the
axillary vein. The brachial plexus of nerves bears the following relation to the
artery in this part of its course : on the outer side is the median nerve, and the
musculo-cutaneous for a short distance; on the inner side, the ulnar, the internal,
and lesser internal cutaneous nerves ; and behind, the musculo- spiral, and cir-
cumflex, the latter extending only to the lower border of the Subscapularis
muscle.
Relations of Third Portion of the Axillary Artery.
In front.
Integument and fascia.
PectoraUs major.
Oitter side. / * -n \ Inner side.
Coraco-brachialis. / -^^ll^ry
Median nerve. Artery. ^u.^^yu.<x.L v.uua^
Musculo-cutaneous nerve. Vi liircl portiony Axillary vein.
Ulnar nerve.
Internal cutaneous nerves.
Behind.
Subscapularis.
Tendons of Latissimus dorsi, and Teres major.
Musculo-spiral, and circumflex nerves.
AXILLARY. 351
Peculiarities. The axillary artery, in about one case out of every ten, gives off a large
branch, which forms either one of the arteries of the forearm, or a large muscular tnink.
In the first set of cases this artery is most frequently the radial (1 in 33), sometimes the
ulnar (1 in 72), and very rarely, the interosseous (1 in 506). In the second set of cases,
the trunk gave origin to the subscapular, circumflex, and profunda arteries of the arm.
Sometimes only one of the circumflex, or one of the profunda arteries, arose from the
trunk. In these cases the brachial plexus surrounded the trunk of the branches, and not
the main vessel.
Surgical Anatomy. The student having carefully examined the relations of the axillary
artery in its various parts, should now consider in what situation compression of this
vessel may be most easily effected, and the best position for the application of a ligature
to it when necessary.
Compression of this vessel is required in the removal of tumours, or in amputation of
the upper part of the arm ; and the only situation in which this can be effectually made,
is in the lower part of its course, just beneath the integument and fascia; and on com-
pressing it from within outwards upon the humerus, the circulation may be efficiently
suspended.
The application of a ligature to the axillary artery may be required, in cases of aneurism
of the upper part of the brachial ; and there are only two situations in which it may be
secured, viz., in the upper, or in the lower part of its course.
The axillary artery at its central part is so deeply seated, and, at the same time, so closely
surrounded vsdth large nervous trunks, that the application of a ligature to it would be
almost impracticable.
In the lower part of its course the operation is more simple, and may be performed in
the following manner : — The patient being placed on a bed, and the arm separated from
the side, with the hand supinated, the head of the humerus is felt for, and an incision
made through the integument over ifc, about two inches in length, a little nearer to the
posterior than the anterior fold of the axilla. After carefully dissecting through the
areolar tissue and fascia, the median nerve and axillary vein are exposed ; the former
having been displaced to the outer, and the latter to the inner side of the arm, the elbow
being at the same time bent so as to relax these structures, and facilitate their separation,
the ligature may be passed around the artery from the ulnar to the radial side.
The upper portion of the axillary artery may be tied, in cases of aneurism encroaching
so far upwards that a ligature cannot be applied in the lower part of its course. Notwith-
standing that this operation has been performed in some few cases, and with success, its
performance is attended with much difficulty and danger. The student will remark, that
in this situation, it would be necessary to divide a thick muscle, and, after separating the
costo-coracoid membrane, the artery would be exposed at the bottom of a more or less
deep space, with the cephalic and axillary veins in such relation with it as must render the
application of a hgature to this part of the vessel particularly hazardous. Under such
circumstances it is an easier, and, at the same time, more advisable operation, to tie the
subclavian artery in the third part of its course.
In a case of wound of this vessel, the general practice of cutting down upon, and tying
the vessel above and below the wounded point, should be adopted in all cases.
The branches of the axillary artery are, the
7-- . r, f Superior thoracic.
rrom 1st Fart, i . • 1 .i
y Acromial thoracic.
T-. 7 7-. . ( Thoracica lonaja.
rrom ind Fart, i rm • i •
( inoracica a,laris.
{Subscapular.
Anterior circumflex.
Posterior circumflex.
The Superior Thoracic is a small artery, which arises from the axillary, or by
a common trunk with the acromial thoracic. Running forwards and inwards
along the upper border of the Pectoralis minor, it passes between it and the Pec-
toralis major to the side of the chest. It supplies these muscles, and the parietes
of the thorax, anastomosing with the internal mammary and intercostal arteries.
The Acromial Thoracic is a short trunk, which arises from the fore part of the
axillary artery. Projecting forwards to the upper border of the Pectoralis minor,
it divides into three sets of branches, thoracic, acromial, and descending. The
thoracic branches, two or three in number, are distributed to the Serratus magnus
and Pectoral muscles, anastomosing with the intercostal branches of the internal
mammary. The acromial branches are directed outwards towards the acromion,
352 ARTERIES.
supplying the Deltoid muscle, and anastomosing, on the surface of the acromion,
with the supra-scapular and posterior circumflex arteries. The descending branch
passes in the inter-space between the Pectoralis major and Deltoid, accompanying
the cephalic vein, and supplying both muscles.
The Long Thoracic passes downwards and inwards along the lower border
of the Pectoralis minor to the side of the chest, supplying the Serratus magnus,
the Pectoral muscles, and mammary gland, and sending branches across the axilla
to the axillary glands and Subscapularis, which anastomose with the internal
mammary and intercostal arteries.
The Thoracica Alaris is a small branch, which supplies the glands and areolar
tissue of the axilla. Its place is frequently supplied by branches from some of
the other thoracic arteries.
The Subscapular, the largest branch of the axillary artery, arises opposite the
lower border of the Subscapularis muscle, and passes downwards and backwards
along its lower margin to the inferior angle of the scapula, where it anastomoses
with the posterior scapular, a branch of the subclavian. It distributes branches
to the Subscapularis, the Serratus magnus. Teres major, and Latissimus dorsi
muscles, and gives off, about an inch and a-half from its origin, a large branch, the
dorsalis scapulae. This vessel curves round the inferior border of the scapula,
leaving the axilla in the inter- space between the Teres minor above, the Teres major
below, and the long head of the Triceps in front; and divides into three branches,
a subscapular, which enters the subscapular fossa beneath the Subscapularis which
it supplies, anastomosing with the subscapular and supra- scapular arteries; an
infra-spinous branch (dorsalis scapulae), which turns round the axillary border of
the scapula, between the Teres minor and the bone, enters the infra-spinous fossa,
supplies the Infra-spinatus muscle, and anastomoses with the supra-scapular and
posterior scapular arteries; and a median branch, which is continued along the
axillary border of the scapula, between the Teres major and minor, and, at the dorsal
surface of the inferior angle of the bone, anastomoses with the supra-scapular.
The Circumflex Arteries wind around the neck of the humerus.
The Posterior, the larger of the two, arises from the back part of the axillary,
opposite the lower border of the Subscapularis muscle, and, passing backwards
with the circumflex veins and nerve, through the quadrangular space bounded by
the Teres major and minor, the scapular head of the Triceps and the humerus,
winds around the neck of that bone, is distributed to the Deltoid muscle and
shoulder-joint, anastomosing with the anterior circumflex, supra-scapular, and
acromial thoracic arteries.
The Anterior Circumjlex, considerably smaller than the preceding, arises just
below that vessel, from the outer side of the axillary artery. It passes horizon-
tally outwards, beneath the coraco-brachialis and short head of the Biceps, lying
upon the fore part of the neck of the humerus, and, on reaching the bicipital
groove, gives off an ascending branch, which passes upwards along it, to supply
the head of the bone and the shoulder -joint. The trunk of the vessel is then
continued outwards beneath the Deltoid which it supplies, and anastomoses with
the posterior circumflex, and acromial thoracic arteries.
Brachial Artery (fig. 200).
The brachial artery commences at the lower margin of the tendon of the Teres
major, and, passing down the inner and anterior aspect of the arm, terminates
about half an inch below the bend of the elbow, where it divides into the radial
and ulnar arteries.
The direction of this vessel is marked by a line drawn from the outer side of
the axillary space between the folds of the axilla, to a point midway between
the condyles of the humerus, which corresponds to the depression along the
inner border of the Coraco-brachialis and Biceps muscles. In the upper part
BRACHIAL.
353
of its course, this vessel lies internal 200
to the humerus; but below, it is in
front of that bone.
Relations. This artery is super-
ficial throughout its entire extent,
being covered, in front, by the in-
tegument, the superficial and deep
fascife ; the bicipital fascia separates
it opposite the elbow from the me-
dian basilic vein, the median nerve
crosses it at its centre, and the ba-
silic vein lies in the line of the ar-
tery for the lower half of its course.
Behind, it is separated from the
inner side of the humerus above, by
the long and inner heads of the Tri-
ceps, the musculo-spiral nerve and
superior profunda artery interven-
ing ; and from the front of the bone
below, by the insertion of the Co-
raco-brachialis and the Brachialis
anticus muscles. By its outer side,
it is in relation with the commence-
ment of the median nerve, and the
Coraco-brachialis and Biceps mus-
cles, which slightly overlap the ar-
tery. By its inner side, with the
internal cutaneous and ulnar nerves,
its upper half; the median nerve,
its lower half. It is accompanied
by two veins, the venae comites;
they lie in close contact with the
artery, being connected together
at intervals by short transverse
communicating branches.
-The Surgical Anatomy of the Brachial Artery.
npe/rUn-
Frofu/nda,
Inferior
Profunda
Anastomo tCca
Plan of the Relations of the Brachial Artery.
In front.
Integument and fasciae.
Bicipital fascia, median basilic vein.
Median nerve.
Outer side.
Median nerve.
Coraco-brachialis.
Biceps,
Inner side.
Internal cutaneous.
Ulnar and median nerves.
Behind.
Triceps.
Musculo-spiral nerve.
Superior profunda artery.
Coraco brachialis.
Brachialis anticus.
354 ARTERIES.
Bend of the Elbow.
At the bend of the elbow, the brachial artery sinks deeply into a triangular in-
terval, the base of which is directed upwards towards the humerus, and the sides
of which are bovinded, externally, by the Supinator longus, internally, by the Pro-
nator radii teres ; its floor is formed by the Brachialis anticus, and Supinator brevis.
This space contains the brachial artery, with its accompanying veins; the radial
and ulnar arteries, the median and musculo-spiral nerves, and the tendon of the
Biceps. The brachial artery occupies the middle line of this space, and divides
opposite the coronoid process of the ulna into the radial and ulnar arteries; it is
covered, in front,hj the integument, the superficial fascia, and the median basilic vein,
the vein being separated from direct contact with the artery by the bicipital fascia.
Behind, it lies on the Brachialis anticus, which separates it from the elbow-joint.
The median nerve lies on the inner side of the artery, but separated from it below
by an interval of half an inch. The tendon of the Biceps lies to the outer side
of the space, and the musculo-spiral nerve still more externally, lying upon the
Supinator brevis, and partly concealed by the Supinator longus.
Peculiarities of the Artery as regards its Course. The brachial artery, accompanied by the
median nerve, may leave the inner border of the Biceps, and descend towards the inner con-
dyle of the humerus, where it usually curves around a prominence of bone, to which it is
connecter 1 by a fibrous band ; it then inclines outwards, beneath or through the substance
of the Pronator teres muscle, to the bend of the elbow. This variation bears considerable
analogy with the normal condition of the artery in some of the carnivora.
As regards its Division. Occasionally, the artery is divided for a short distance at its
upper part into two trunks, which are united above and below. A similar pecuUarity occurs
in the main vessel of the lower limb.
The point of bifurcation may be above or below the usual point, the former condition
being by far the most frequent. Out of 481 examinations recorded by Mr. Quain, some
made on the right and some on the left side of the body, in 386 the artery bifurcated in
its normal position. In one case only was the place of division lo\ver than usual, being
two or three inches below the elbow-joint. 'In ninety cases out of 481, or about i in 5^,
there were two arteries instead of one in some part, or in the whole of the arm.'
There appears, however, to be no correspondence between the arteries of the two arms,
with respect to their irregular division ; for in sixty-one bodies it occurred in one side only
in forty-three ; on both sides, in different positions, in thirteen ; on both sides, in the same
position, in five.
The point of bifurcation takes place at different parts of the arm, being most frequent
in the upper part, less so in the lower part, and least so in the middle, the most usual
point for the application of a ligature ; under any of these circumstances two large arteries
would be found in the arm instead of one. The most frequent (in three out of four) of these
peculiarities is the high division of the radial. It often arises from the inner side of the
brachial, and runs parallel with the main trunk to the elbow, where it crosses it, lying
beneath the fascia ; or it may perforate the fascia, and pass over the artery, immediately
beneath the integument.
The ulnar sometimes arises from the brachial high up, and then occasionally leaves that
vessel at the lower part of the arm, and descends towards the inner condyle. In the
fore-arm it generally hes beneath the deep fascia, superficial to the Flexor muscles ; occa-
sionally between the integument and deep fascia, and very rarely beneath the Flexor
muscles.
The interosseous artery sometimes arises from the upper part of the brachial or axillary:
as it descends the arm it lies behind the main trunk, and at the bend of the elbow regains
its usual position.
In some cases of high division of the radial, the remaining trunk (ulnar interosseous)
occasionally passes, together with the median nerve, along the inner margin of the arm to
the inner condyle, and then passing from within outwards, beneath or through the Pronator
teres, regains its usual position at the bend of the elbow.
Occasionally, the two arteries representing the brachial are connected at the bend of the
elbow by a short transverse branch, and are even sometimes reunited.
Sometimes long slender vessels, vasa aberrantia, connect the brachial or axillary arteries
with one of the arteries of the fore-arm, or a branch from them. These vessels usually
join the radial.
In some subjects the brachial artery is covered by an additional slip from the Biceps or
Brachialis anticus muscles ; and occasionally a slip from the latter muscle covers the
whole extent of the ulnar interosseous trunk in cases ol high division of the radial.
Surgical Anatomy. Compression of the brachial artery is required in cases of amputation
SUEGICAL ANATOMY OF BRACHIAL ARTERY. 355
of the arm or fore-arm, in resection of the elbow-joint, and the removal of tumours ; and
it will be observed, that it may be effected in almost any part of its course ; if pressure is
made in the upper part of the limb it should be directed from within outwards, and if in
the lower part, from before backwards, as the artery lies on the inner side of the humei-us
above, and in front of it below. The most favourable situation is either above or below
the insertion of the Coraco-brachialis.
The application of a ligature to the brachial artery may be required in cases of wounds
of the vessel, or of aneurism of the brachial, the radial, ulnar, or interosseous arteries ; and
this vessel may be secured in any part of its course. The chief guides in determining its
position are the surface-markings produced by the inner margin of the Coraco-brachialis
and Biceps, the known course of the vessel, and its pulsation, which should be carefully
felt for before any operation is performed, as the vessel occasionally deviates from its usual
position in the arm. In whatever situation the operation is performed, great care is neces-
sary on account of the extreme thinness of the parts covering the artery, and the intimate
connection which the vessel has throughout its whole course with important nerves and
veins. Sometimes a thin layer of muscular fibre is met with concealing the artery ; if
such is the case, it must be divided across, in order to expose it.
In the tipper third of the arm the artery may be exposed in the following manner. The
patient being placed horizontally upon a table, the affected limb should be raised from the
side, and the hand supinated. An incision about two inches in length should be made on
the ulnar side of the Coraco-brachialis muscle, and the subjacent fascia cautiously divided
so as to avoid wounding the internal cutaneous nerve or basilic vein, which sometimes
runs on the surface of the artery as high as the axilla. The fascia having been divided, it
should be remembered, that the ulnar and internal cutaneous nerves lie on the inner side
of the artery, the median on the outer side, the latter nerve being occasionally superficial
to the artery in this situation, and that the vense comites are also in relation with the
vessel, one on either side. These being carefully separated, the aneurism needle should be
passed around the artery from the ulnar to the radial side.
If two arteries are present in the arm in consequence of a high division, they are usually
placed side by side ; and if they are exposed in an operation, the surgeon should endeavour
to ascertain, by alternately pressing on one or the other vessel, which of the two commu-
nicates with the wound or aneurism, when a ligature may be applied accordingly ; or if
pulsation or haemorrhage ceases only when both vessels are compressed, both vessels may
be tied, as it may be concluded that the two communicate above the seat of disease or are
reunited.
It should also be remembered, that two arteries may be present in the arm in a case of
high division, and that one of these may be found along the inner intermuscular septum,
in a line towards the inner condyle of the humerus, or in its usual position, but deeply
placed, beneath the common trunk : a knowledge of these facts will at once suggest the
precautions necessary in every case, and indicate the necessary measure to be adopted when
met with.
hi the middle of the arm the brachial artery may be exposed by making an incision along
the inner margin of the Biceps muscle. The fore-arm being bent so as to relax the muscle,
it should be drawn slightly aside, and the fascia being carefully divided, the median nerve
will be exposed lying upon the ai-tery (sometimes beneath) ; this being dra^vn inwards and
the muscle outwai'ds, the artery should be separated from its accompanying veins and
secured. In this situation the inferior profunda may be mistaken for the main trunk,
especially if enlarged, from the collateral circulation having become established ; this
may be avoided by directing the incision externally towards the Biceps, rather than in-
wards or backwards towards the Triceps.
The lower part of the brachial artery is of extreme interest in a surgical point of view,
on account of the relation which it bears to those veins most commonly opened in vene-
section. Of these vessels, the median basilic is the largest and most prominent, and, con-
sequently, the one usually selected for the operation. It should be remembered, that this
vein runs parallel with the brachial artery, from which it is separated by the bicipital
fascia, and that in no case should this vessel be selected for the operation, except in a
part which is not in contact with the artery.
The branches of the brachial artery are the
Superior profunda. Inferior profunda.
Nutrient artery. Anastomotica magna.
Muscular.
The Superior Profunda arises from the inner and back part of the brachial,
opposite the lower border of the Teres major, and passes backwards to the
interval between the outer and inner heads of the Triceps muscle, accompanied
by the musculo-spiral nerve ; it winds around the back part of the shaft of the
humerus in the spiral groove, between the Triceps and the bone, and descends on
the outer side of the arm to the space between the Brachialis anticns, and
A A 2
356
ARTERIES.
Supinator longus, as far as the elbow, where it anastomoses with the recurrent
branch of the radial artery. It supplies the Deltoid, Coraco-bracahilis, and
Triceps muscles, and whilst
201. — The Surgical Anatomy of the Eadial and Ulnar in the groove, between the
Arteries. Triceps and the bone, it
gives off the posterior ar-
ticular artery, which de-
scends perpendicularly be-
tween the Triceps and the
bone, to the back part of
the elbow-joint, where it
anastomoses with the inter-
osseous recurrent branch,
and, on the inner side of
the arm, with the ulnar
recurrent, and with the
anastomotica magna or in-
ferior profunda (fig. 203).
The Nutrient artery of
the shaft of the humerus
arises from the brachial,
about the middle of the arm.
Passing downwards, it en-
ters the nutritious canal of
that bone, near the inser-
tion of the Coraco-brachia-
lis muscle.
The Inferior Profunda,
of small size, arises from
the brachial, a little below
the middle of the arm ;
piercing the internal inter-
muscular septum, it de-
scends on the surface of
the inner head of the Tri-
ceps muscle, to the space
between the inner condyle
and olecranon, accompa-
nied by the ulnar nerve,
and terminates by anasto-
mosing with the posterior
ulnar recurrent, and ana-
stomotica magna.
The Anastomotica Mag-
na arises from the brachial,
about two inches above the
elbow-joint. It passes
transversely inwards upon
the Brachialis anticus, and,
piercing the internal inter-
muscular septum, winds
around the back part of the
humerus, between the Tri-
ceps and the bone, forming
an arch above the olecra-
non fossa, by its junction
with the posterior articular
'Jie^ hntnaA of VT/ntbr
jSiiperfictafts Vulot
RADIAL.
357
branch of the superior profunda. As this vessel lies on the Brachialis anticus, an
oifset passes between the internal condyle and olecranon, where it anastomoses
with the inferior profunda and posterior ulnar recurrent arteries. Other branches
ascend to join the inferior profunda ; and some descend in front of the inner
condyle, to anastomose with the anterior ulnar recurrent.
The Muscular are three or four large branches, which are distributed to the
muscles in the course of the artery. They supply the Coraco-brachialis, Biceps,
and Brachialis anticus muscles.
Radial Artery.
The Radial artery appears, from its direction, to be the continuation of the
brachial, but, in size, it is smaller than the ulnar. It commences at the bifurca-
tion of the brachial, just below the bend of the elbow, and passes along the radial
side of the fore-arm to the wrist ; it then winds backwards, round the outer side
of the carpus, beneath the extensor tendons of the thumb, and, running forwards,
passes between the two heads of the first Dorsal interosseous muscle, into the
palm of the hand. It then crosses the metacarpal bones to the ulnar border of the
hand, forming the deep palmar arch, and, at its termination, inosculates with the
deep branch of the ulnar artery. The relations of this vessel may thus be con-
veniently divided into three parts, viz., in front of the fore-arm, at the back of the
wrist, and in the hand.
Relations. In the fore-arm, this vessel extends from opposite the neck of the
radius, to the fore part of the styloid process, being placed to the inner side of the
shaft of that bone above, and in front of it below. It is superficial throughout its
entire extent, being covered by the integument, the superficial and deep fasciae, and
slightly over-lapped superiorly by the Supinator longus. In its course downwards
it lies upon the tendon of the Biceps, the Supinator brevis, the Pronator radii
teres, radial origin of the Flexor sublimis digitorum, the Flexor longus pollicis.
Pronator quadratus, and the lower extremity of the radius. In the upper third
of its course, it lies between the Supinator longus and the Pronator radii teres ;
in its lower two thirds, between the tendons of the Supinator longus and the
Flexor carpi radialis. The radial nerve lies along the outer side of the artery, in
the middle third of its course ; and some filaments of the musculo-cutaneous nerve,
after piercing the deep fascia, run along the lower part of the artery as it winds
around the wrist. The vessel is accompanied by ven^e comites throughout its
whole course.
Plan of the Relations of the Radial Artery in the Fore-arm.
In front.
Integument — superficial and deep fasciae.
Supinator longus.
Inner side. /p v i + \ Outer side.
Pronator radii teres. /Kadial artery \ Supinator longus.
Flexor carpi radiahs, \ ^^ Fore-arm. I Eadial nerve (middle
\ / third.)
Behind.
Tendon of Biceps.
Supinator brevis.
Pronator radii teres.
Flexor sublimis digitorum.
Flexor longus poUicis.
Pronator quadratus.
Radius.
At the wrist, as it winds around the outer side of the Carpus, from the styloid
358 ARTERIES.
process to the first interosseous space, it lies upon the external lateral ligament
being covered by the extensor tendons of the thumb, subcutaneous veins, some
filaments of the radial nerve, and the integument. It is accompanied by two
veins, and a filament of the musculo-cutaneous nerve.
In the hand, it passes from the upper end of the first interosseous space,
between the heads of the Abductor indicis, transversely across the palm, to the
base of the metacarpal bone of the little finger, where it inosculates with the
communicating branch from the ulnar artery, forming the deep palmar arch. It.
lies upon the carpal extremities of the metacarpal bones and the Interossei
muscles, being covered by the flexor tendons of the fingers, the Lumbricales, the
muscles of the little finger, and the Flexor brevis pollicis, and is accompanied by
the deep branch of the ulnar nerve.
Peculiarities. The origin of the radial artery varies in the proportion nearly of one in
eight cases. In one case the origin was lower than usual. lu the other cases, the upper
part of the brachial was a more frequent source of origin than the axillary. The varia-
tions in the position of this vessel in the arm, and at the bend of the elbow, have been
already mentioned. In the fore- arm it deviates less frequently from its position than the
ulnar. It has been found lying over the fascia, instead of beneath it. It has also been
observed on the surface of the Supinator longus, instead of along its inner border ; and in
turning round the wiist, it has been seen lying over, instead of beneath, the Extensor
tendons.
Surgical Anatomy. The operation of tying the radial artery is required in cases of wounds
either of its trunk, or of some of its branches, or for aneurism : and it will be observed, that
the vessel may be easily exposed in any part of its course through the fore-arm. This ope-
ration in the middle or inferior third of this region is easily performed; but in the upper
third, near the elbow, the operation is attended with some difficulty, from the greater depth
of the vessel, and from its being overlapped by the Supinator longus and Pronator teres
muscles.
To tie the artery in this situation, an incision three inches in length should be made
through the integument, from the bend of the elbow obliquely downwards and outwards,
on the radial side of the fore-arm, avoiding the branches of the median vein ; the fascia of
the arm being divided, and the Supinator longus drawn a little outwards, the artery will be
exposed. The venae comites should be carefully separated from the vessel, and the ligature
passed from the radial to the ulnar side.
In the middle third of the fore-arm the artery may be exposed by making an incision of
similar length on the inner margin of the Supinator longus. In this situation the radial
nerve lies in close relation with the outer side of the artery, and should, as well as the veins,
be carefully avoided.
In the inferior third, the artery is easily secured by dividing the integument and fasciae
in the interval between the tendons of the Supinator longus and Flexor carpi radialis
muscles.
The branches of the radial artery may be divided into three groups, corre-
sponding Vt^ith the three regions in which this vessel is situated.
( Radial recurrent.
In the j Muscular.
Fore-arm. J Superficialis volas.
(. Anterior Carpal.
[ Posterior carpal.
Wrist. ) Metacarpal. ^ •
I Dorsales pollicis.
i Dorsalis indicis.
( Princeps pollicis.
) Radialis indicis.
I Perforantes.
V Interossei.
Hand.
The Radial Recurrent is given oiF immediately below the elbow. It ascends be-
tween the branches of the musculo-spiral nerve, lying on the Supinator brevis, and then
between the Supinator longus and Brachialis anticus, supplying these muscles, the
elbow-joint, and anastomosing with the terminal branches of the superior profunda.
BRANCHES OF RADIAL.
359
The Muscular Branches ai'e distributed to the muscles on the radial side of the
fore-arm.
The Superjicialis VolcB arises from the radial artery, just where this vessel is
about to wind around the wrist. Running forwards, it passes between the muscles
of the thumb, which it supplies, and anastomoses with the termination of the ulnar
artery, completing the superficial palmar arch. This vessel varies considerably in
size, usually it is very small, and terminates in the muscles of the thumb; some-
times it is as large as the continuation of the radial.
The Carpal branches supply the joints of the wrist. The Anterior Carpal is a
small vessel which arises from the radial artery near the lower border of the Pro-
nator quadratus, and running in-
wards in front of the radius, ana-
stomoses with the anterior carpal
branch of the ulnar artery. From
the arch thus fonned, branches
descend to supply the articulations
of the wrist.
The Posterior Carpal is a small
vessel which arises from the radial
artery beneath the extensor tendons
of the thumb; crossing the carpus
transversely to the inner border of
the hand, it anastomoses with the
posterior carpal branch of the ulnar.
Superiorly it sends branches up-
wards, which anastomose with the
termination of the anterior inter-
osseous artery. Other branches
descend to the metacarpal spaces;
they are the dorsal interosseous ar-
teries for the third and fourth in-
terosseous spaces; they anastomose
with the posterior perforating
branches from the deep palmar
arch.
The Metacarpal {First Dorsal
Interosseous Branch) arises beneath
the extensor tendons of the thumb,
sometimes with the posterior carpal
artery; running forwards on the
second dorsal interosseous muscle;
it communicates, behind, with the
corresponding perforating branch of
the deep palmar arch; and, in front,
inosculates with the digital branch
of the superficial palmar arch, and
supplies the adjoining sides of the
index and middle fingers.
The Dor sales Pollicis are two
small vessels which run along the
sides of the dorsal aspect of the
thumb. They sometimes arise se-
parately, or occasionally by a com-
mon trunk, near the base of the
first metacarpal bone.
The Dorsalis Indicis, also a
small branch, runs along the radial
-Ulnar and Radial Arteries.
Deep View.
ntisi'oty/oiicfc
Anier,
Heeurreitt
-Pas'fsria'r Ulnar
Me.
Deep iraxch of V2nar
360 ARTERIES.
side of the back of the index finger, sending a few branches to the Abductor
indicis.
The Prineeps Pollicis arises from the radial just as it turns inwards to the deep
part of the hand; it descends between the Abductor indicis and Adductor pollicis,
along the ulnar side of the metacarpal bone of the thumb, to the base of the first
phalanx, where it divides into two branches, which run along the sides of the
palmar aspect of the thumb, and form an arch on the under surface of the last
phalanx, from which branches are distributed to the integument and cellular
membrane of the thumb.
The Radialis Indicis arises close to the preceding, descends between the Ab-
ductor indicis and Adductor pollicis, and runs along the radial side of the index
finger to its extremity, where it anastomoses with the collateral digital artery from
the superficial palmar arch. At the lower border of the Adductor pollicis this
vessel anastomoses with the prineeps pollicis, and gives a communicating branch
to the superficial palmar arch.
The Perforantes, three in number, pass backwards between the heads of the
last three Dorsal interossei muscles, to inosculate with the dorsal interosseous
arteries.
The Palmar Interossei, three or four in number, are branches of the deep
palmar arch; they run forwards upon the Interossei muscles, and anastomose at the
clefts of the fingers with the digital branches of the superficial arch.
Ulnar Artery.
The Ulnar Artery, the larger of the two sub-divisions of the brachial, com-
mences a little below the bend of the elbow, and crosses the inner side of the fore-
arm obliquely to the commencement of its lower half; it then runs along its ulnar
side to the wrist, crosses the annular ligament on the radial side of the pisiform
bone, and passes across the palm of the hand, forming the superficial palmar arch,
which terminates by inosculating with the superficialis volae.
Relations in the Fore-arm. In its upper half, it is deeply seated, being covered
by all the superficial Flexor muscles, excepting the Flexor carpi ulnaris; crossed
by the median nerve, which, at its origin, for about an inch lies to its inner side;
and it lies upon the Brachialis anticus and Flexor profundus digitorum muscles.
In the lower half of the fore-arm, it lies upon the Flexor profundus, being covered
by the integument, the superficial and deep fasciae, and is placed between the
Flexor carpi ulnaris and Flexor sublimis digitorum muscles. It is accompanied
by two veins, which lie one on each side of the vessel; the ulnar nerve lies on its
inner side for the lower two thirds of its extent, and a small branch from it
descends on the lower part of the vessel to the palm of the hand.
Plan op Relations of the Ulnar Artery in the Fore-arm,
In front.
Superficial flexor muscles, ) tt x, ^e
Median nerve, \ ^^P^^ '^''^■
Superficial and deep fasciae. Lower half.
Inner side. f Ulnar , n t 'rJ
Flexor carpi ulnaris. / Artery in I „, Outer side.
Ulnar nerve (lower two-thirds.) I Fore-arm. / ^^^^""'^ sublimis digitorum.
Behind.
Brachialis anticus.
Flexor profundus digitorum.
At the wrist, the ulnar artery is covered by the integument and fascia, and lies
upon the anterior annular ligament. On its inner side is the pisiform bone. The
ulnar nerve lies at the inner side, and somewhat behind the artery.
ULNAR. 361
In the palm of the hand, the continuation of the ulnar artery is called the
superficial palmar arch; it passes obliquely outwards to the interspace between
the ball of the thumb and the index finger, where it anastomoses with the super-
ficialis volfe, and a branch from the radialis indicis, thus completing the super-
ficial palmar arch. The convexity of this arch is directed towards the fingers, its
concavity towards the muscles of the thumb.
The superficial palmar arch is covered by the Palmaris brevis, the palmar fascia,
and integument; and lies upon the annular ligament, the muscles of the little finger,
the tendons of the superficial Flexor, and the divisions of the median and ulnar
nerves, the latter accompanying the artery a short part of its course.
Relations of the Superficial Palmar Arch.
In front. /^ N. Behind.
Integument. / Ulnar \, Annular ligament.
Palmaris brevis. Artery in Origin of muscles of little finger.
Palmar fascia. \ Hand. / Superficial flexor tendons.
\ / Divisions of median and ulnar nerves.
Peculiarities. The ulnar artery was found to vary in its origin nearly in the proportion
of one in thirteen cases, in one case arising lower than usual, about two or three inches
below the elbow, and in all the other cases much higher, the brachial being a more
frequent source of origin than the axillary.
Variations in the position of this vessel are more frequent than in the radial. When its
origin is normal, the course of the vessel is rarely changed. When it arises high up, its
position in the fore-arm is almost invariably superficial to the Flexor muscles, lying
commonly beneath the fascia, more rarely between the fascia and integument. In a few
cases, its position was subcutaneous in the upper part of the fore-arm, sub-aponeu-
rotic in the lower part.
Surgical Anatomy. The application of a ligature to this vessel is required in cases of
wound of the artery, or of its branches, or in consequence of aneurism. In the upper half
of the fore-arm, the artery is deeply seated beneath the superficial Flexor muscles, and
their division would be requisite in a case of recent wound of the artery in this situation,
in order to secure it, but under no other circumstances. In the middle and inferior thirds
of the fore-arm, this vessel may be easily secured by making an incision on the radial side
of the tendon of the Flexor carpi ulnaris ; the deep fascia being divided, and the Flexor
carpi ulnaris and its companion muscle, the Flexor sublimis, being separated from each
other, the vessel will be exposed, accompanied by its venae comites, the ulnar nerve lying
on its inner side. The veins being separated from the artery, the hgature should be passed
from its ulnar to its radial side, taking care to avoid the iilnar nerve.
The branches of the ulnar artery may be arranged into three groups,
Anterior ulnar recurrent.
Posterior ulnar recurrent.
I
Muscular.
TWT • . ( Anterior carpal.
( Posterior carpal.
( Deep or communicating branch.
\ Digital.
Fore-arm. < ^ , \ Anterior interosseous.
Interosseous i -n , • • .
Posterior interosseous.
Hand.
The Anterior Ulnar Recurrent arises immediately below the elbow-joint, passes
upwards and inwards between the Brachialis anticus and Pronator radii teres, sup-
plies these muscles, and, in front of the inner condyle, anastomoses with the
anastomotica magna and inferior profunda.
The Posterior Ulnar Recurrent is much larger, and arises somewhat lower than
the preceding. It passes backwards and inwards, beneath the Flexor sublimis,
and ascends behind the inner condyle of the humerus. In the interval between
362
ARTERIES.
Aiitisto
Fbxte
XIlTmirSeeur
this eminence and the olecranon, it lies beneath the Flexor carpi ulnaris, asceud-
ino- between the heads of that muscle, beneath the ulnar nerve; it supplies the
neighbouring muscles and joint, and anastomoses with the inferior profunda,
anastomotica magna, and interosseous recurrent arteries.
The Interosseous Artery is a short trunk, about an inch in length, and of con-
siderable size, which arises immediately below the bicipital tuberosity of the radius,
and, passing backwards to the upper border of the interosseous membrane, divides
into two branches, the anterior, and posterior interosseous.
Th.Q Anterior Interosseous
203.-Arteries of the Back of the Fore-arm and Hand. ^^^^^^ ^^^ ^^^ fore-arm
on the anterior surface of
the interosseous membrane,
to which it is connected by
a thin aponeurotic arch. It
is accompanied by the in-
terosseous branch of the
median nerve, and over-
lapped by the contiguous
margins of the Flexor pro-
fundus digitorum and Flexor
longus pollicis muscles,
giving off in this situation
muscular branches, and the
nutrient arteries of the ra-
dius and ulna. At the up-
per border of the Pronator
quadratu ;s, a branch descends
in front of that muscle, to
anastomose in front of the
carpus with the branches
from the anterior carpal and
deep palmar arch. The con-
tinuation of the artery passes
behind the Pronator qua-
dratus, and, piercing the in-
terosseous membrane, de-
scends to the back of the
wrist, where it anastomoses
with the posterior carpal
branches of the radial and
ulnar arteries. The anterior
interosseous gives off a long,
slender branch, which ac-
companies the median
nerve, and gives off-sets to
its substance. This, the
median artery, is sometimes
much enlarged.
The Posterior Interos-
seous Artery passes back-
wards through the interval
between the oblique liga-
ment and the upper border
of the interosseous mem-
brane, and passes down the
back part of the fore-arm,
between the superficial and
THORACIC AORTA. 363
deep layer of muscles, to both of which it distributes branches. Descending to
the back of the wrist, it anastomoses with the termination of the anterior
interosseous, and with the posterior carpal branches of the radial and ulnar
arteries. This artery gives off, near its origin, the posterior interosseous re-
current branch, a large vessel, which ascends to the interval between the
external condyle and olecranon, beneath the Anconeus and Supinator brevis,
anastomosing with a branch from the supi«a#0ii profunda, and with the posterior
ulnar recurrent arteries.
The Muscular Branches are distributed to the muscles along the ulnar side of
the fore-arm.
The Carpal Branches are intended for the supply of the wrist-joint.
The Anterior Carpal is a small vessel, which crosses the anterior surface of the
carpus beneath the tendons of the Flexor profundus, and inosculates with a cor-
responding branch of the radial artery.
The Posterior Carpal arises immediately above the pisiform bone, winding
backwards beneath the tendon of the Flexor carpi ulnaris; it gives oif a branch
which passes across the dorsal surface of the carpus beneath the extensor tendons,
anastomosing with a corresponding branch of the radial artery, and forming the
posterior carpal arch; it is then continued along the metacarpal bone of the
little finger, forming its dorsal branch.
The Deep or Communicating Branch arises at the commencement of the palmar
arch, passing deeply inwards between the Abductor minimi digiti and Flexor bre-
vis minimi digiti, near their origins; it anastomoses with the termination of the
radial artery, completing the deep palmar arch.
The Digital Branches, four in number, are given off from the convexity of the
superficial palmar arch. They supply the ulnar side of the little finger, and the
adjoining sides of the ring, middle, and index fingers; the radial side of the
index finger and thumb being supplied from the radial artery. The digital arteries
at first lie superficial to the flexor tendons, but as they pass forwards with the
digital nerves to the clefts between the fingers, they lie between them, and are
there joined by the interosseous branches from the deep palmar arch. The digital
arteries on the sides of the fingers lie beneath the digital nerves; and, about the
middle of the last phalanx, the two branches for each finger, form an arch,
from the convexity of which branches pass to supply the matrix of the nail.
The Descending Aorta.
The descending aorta is divided into two portions, the thoracic, and abdominal,
in correspondence with the two great cavities of the trunk in which it is
situated.
The Thoracic Aorta commences at the lower border of the third dorsal
vertebra, on the left side, and terminates at the aortic opening in the Diaphragm
in front of the last dorsal vertebra. At its commencement, it is situated on the
left side of the spine; it approaches the median line as it descends, and, at its
termination, lies directly in front of the column. The direction of this vessel
being influenced by the spine, upon which it rests, it is concave forwards in the
dorsal region, and, as the branches given off from it are small, the diminu-
tion in the size of the vessel is inconsiderable. It is contained in the back part
of the posterior mediastinum, being in relation in front, from above downwards,
with the left pulmonary artery, the left bronchus, the pericTrdium, and the
oesophagus; behind, with the vertebral column, and the vena azygos minor; on
the right side, with the vena azygos major, and thoracic duct; on the left side,
with the left pleura and lung. The oesophagus, with its accompanying nerves,
lies on the right side of the aorta above ; in front of this vessel, in the middle of
its course; whilst, at its lower part, it is on the left side, on a plane anterior
to it.
3^4
ARTERIES.
Plan of the Relations of the Thoracic Aorta.
In front.
Left pulmonary artery.
Left bronchus.
Pericardium.
(Esophagus.
Bight side.
CEsophagus (above).
Vena azygos major.
Thoracic duct.
Left side.
Pleura.
Left lung.
CEsophagus (below).
Behind.
Vertebral column.
Vena azygos minor.
Surgical Anatomy. The student should now consider the effects likely to be produced
by aneurism of the thoracic aorta, a disease of common occurrence. When we consider
the great depth of the vessel from the surface, and the number of important structures
which surround it on every side, it may be easily conceived what a variety of obscure
symptoms may arise, from disease of this part of the arterial system, and how they may
be liable to be mistaken for those of other affections. Aneurism of the thoracic aorta
most usually extends backwards, along the left side of the spine, producing absorption of
the bodies of the vertebrse, causing extensive curvature of the spine ; whilst the irritation
or pressure on the cord, will give rise to pain, either in the chest, back, or loins, with
radiating pain in the left upper intercostal spaces, from pressure on the intercostal nerves ;
at the same time the tumour may project back on each side of the spine, beneath the
integument, as a pulsating swelling, simulating abscess connected with diseased bone ;
or it may displace the oesophagus, and compress the lung on one or the other side. If the
tumour extend forward, it may press upon and displa^ce the heart, giving rise to palpi-
tation, and other symptoms of disease of that organ ; or it may displace, or even compress,
the oesophagus, causing pain and difficulty of swallowing, as in stricture of that tube, and
ultimately even open into it by ulceration, producing fatal hsemorrhage. If the disease
make way to either side, it may press upon the thoracic duct ; or it may burst into the
pleural cavity, or into the trachea or lung ; and lastly, it may open into the posterior
mediastinum.
Branches of the Thoracic Aorta.
Pericardiac.
Bronchial.
Q^sophageaL
Posterior mediastinaL
Intercostal.
The Pericardiac are a few^ small vessels, irregular in their origin, distributed
to the pericardium.
The Bronchial arteries are the nutrient vessels of the lungs, and vary in
number, size, and origin. That of the right side arises from the first aortic inter-
costal, or by a common trunk w^ith the left bronchial, from the anterior part of
the thoracic aorta. Those of the left side, usually two in number, arise from the
thoracic aorta, one a little lower than the other. Each vessel is directed forwards
to the back part of the corresponding bronchus, along which they run, dividing
and subdividing, upon the bronchial tubes, supplying them, the cellular tissue of
the lungs, the bronchial glands and the oesophagus.
The (Esophageal Arteries, usually four or five in number, arise from the
anterior part of the aorta, and pass obliquely downwards to the oesophagus, form-
ing a chain of anastomoses along that tube, anastomosing with the oesophageal
branches of the inferior thyroid arteries above, and with ascending branches
from the phrenic and gastric arteries below.
The Posterior Mediastinal Arteries are numerous small vessels which supply
the glands and loose areolar tissue in the mediastinum.
ABDOMINAL AORTA. 365
The Intercostal Arteries arise from the posterior part of the aorta. They are
usually ten in number on each side, the superior intercostal space (and occasion-
ally the second one) being supplied by the superior intercostal, a branch of the
subclavian. The right intercostals are longer than the left, on account of the
position of the aorta to the left side of the spine. They pass outwards, across
the bodies of the vertebr£e, to the intercostal spaces, being covered by the pleura,
and crossed by the oesophagus, thoracic duct, sympathetic nerve, and the vena-
azygos major, the left passing beneath the superior intercostal vein, the vena-
azygos minor, and sympathetic. In the intercostal spaces each artery divides
into two branches, an anterior, or proper intercostal branch, which passes out-
wards; and a posterior, or dorsal branch which passes backwards. The anterior
branch passes outwards, at first lying upon the external Intercostal muscle,
covered in front by the pleura and a thin fascia. It then passes between the two
layers of Intercostal muscles, and, having ascended obliquely to the lower border
of the rib above, divides, near the angle of that bone, into two branches ; of these
the larger runs in the groove, on the lower border of the rib above; the smaller
branch along the upper border of the rib below; passing forward, they supply
the Intercostal muscles, and anastomose with the anterior intercostal arteries,
branches of the internal mammary, and with the thoracic branches of the axillary
artery. The first aortic intercostal anastomoses with the superior intercostal,
and the last three, pass between the Abdominal muscles, inosculating with the
epigastric in front, and with the phrenic, and lumbar arteries. Each inter-
costal artery is accompanied by a vein and nerve, the former being above, and the
latter below, except in the upper intercostal spaces, where the nerve is at first
above the artery. The arteries are protected from pressure during the action of
the Intercostal muscles, by fibrous arches thrown across, and attached by each
extremity to the bone.
The Posterior, or Dorsal Branch, of each intercostal artery, passes backwards
to the inner side of the anterior costo-transverse ligament, and divides into a
spinal branch, which supplies the vertebrae, the spinal cord and its membranes,
and a muscular branch, which is distributed to the muscles and integument of
the back.
The Abdominal Aorta (fig. 204).
The Abdominal Aorta commences at the aortic opening of the Diaphragm, in
front of the body of the last dorsal vertebra, and descending a little to the left
side of the vertebral column, terminates on the left side of the body of the fourth
lumbar vertebra, where it divides into the two common iliac arteries. At it lies
upon the bodies of the vertebrae it is convex forwards, the greatest convexity
corresponding to the third lumbar vertebra, which is a little above and to the left
side of the umbilicus.
Relations. It is covered, in front, by the lesser omentum and stomach, behind
which are the branches of the coeliac axis and the solar plexus; below these, by
the splenic vein, the pancreas, the left renal vein, the transverse portion of the
duodenum, the mesentery, and aortic plexus. Behind, it is separated from the
lumbar vertebrae by the left lumbar veins, the receptaculum chyli, and thoracic
duct. On the right side, with the inferior vena cava (the right crus of the
Diaphragm being interposed above), the vena azygos, thoracic duct, and right
semilunar ganglion. On the left side, with the sympathetic nerve and left semi-
lunar ganglion.
366
ARTERIES.
Plan of the Relations of the Abdominal Aorta.
In front.
Lesser omentum and stomach.
Branches of cceliac axis and solar plexus.
Splenic vein.
Pancreas.
Right side.
Right crus of diaphragm.
Inferior vena cava.
Vena azygos.
Thoracic duct.
Right semilunar ganglion.
Left renal vein.
Transverse duodenum.
Mesentery.
Aortic plexus.
Left side.
Sympathetic nerve.
Left semilunar ganglion.
Behind.
Left lumbar veins. Thoracic duct.
Receptaculum chyli. Vertebral column.
204.— The Abdominal Aorta and its Branches.
CCELIAC AXIS. 367
Surgical Anatoin,^. Anenviavas of the abdominal aorta near the cosliac axis communicate
in nearly equal proportion with the anterior and posterior parts of this vessel.
When an aneurismal sac is connected with the back part of the aorta, it usually pro-
duces absorption of the bodies of the vertebrae, and forms a pulsating tumour, that pre-
sents itself in the left hypochondriac or epigastric regions, accompanied by symptoms of
disturbance of the alimentaiy canal. Pain is invariably present, and is usually of two
kinds, a fixed and constant pain in the back, caused by the tumour pressing on or dis-
placing the branches of the solar plexus and splanchnic nerves, and a sharp lancinating
pain, radiating along those branches of the lumbar nerves pressed on by the tumour ;
hence the pain in the loins, the testes, the hypogastrium, and in the lower limb (usually
of the left side). This form of aneurism usually bursts into the peritoneal cavity, or
behind the peritoneum, in the left hypochondriac region ; or it may form a large aneurismal
sac, extending down as low as Poupart's ligament ; haemorrhage in these cases being gene-
rally very extensive, but slowly produced, and never rapidly fatal.
When an aneurismal sac is connected with the front of the aorta near the coeliac axis,
it forms a pulsating tumour in the left hypochondriac or epigastric regions, usually attended
with symptoms of disturbance of the alimentary canal, as sickness, dyspepsia, or consti-
pation, and accompanied by pain, which is constant but nearly always fixed in the loins,
epigastrium, or some part of the abdomen ; the radiating pain being rare, as the lumbar
nerves are seldom imphcated. This form of aneurism may burst into the peritoneal cavity,
or behind the peritoneum, between the layers of the mesentery, or, more rarely, into the
duodenum ; it rarely extends backwards so as to affect the spine.
Branches of the Abdominal Aorta.
Phrenic.
I Gastric. Renal,
Hepatic. Spermatic.
> Splenic. Inferior mesenteric.
Superior mesenteric. Lumbar.
Supra-renal. Sacra media.
The branches may be divided into two sets: i. Those supplying the viscera.
2. Those distributed to the Tvalls of the abdomen.
Visceral Branches. Parietal Branches.
a ] ■ i { Gastric. Phrenic.
. -^ '^1 Coeliac axis \ Hepatic. Lumbar,
viscera / c 1 • q j-
r. \ I Splenic. feacra media.
,. ,. I Superior mesenteric.
disrestion. t p • . • •
'^ \ interior mesenteric.
Supra-renal glands. Supra-renal.
Kidneys. Renal.
Testes. Spermatic.
CcELiAC Axis.
To expose this artery, raise the hver, draw down the stomach, and then tear through the
laj^ers of the lesser omentum.
It is a short thick trunk, about half an inch in length, arising from the aorta,
opposite the margin of the Diaphragm, and passing nearly horizontally forwards
(in the erect posture), divides into three large branches, the gastric, hepatic, and
splenic, occasionally giving off one of the phrenic arteries.
Relations. It is covered, in front, by the lesser omentum. On the right side,
it is in relation with the right semilunar ganglion, and the lobus Spigelii of the
liver. On the left side, with the left semilunar ganglion and cardiac end of the
stomach. Below, it rests upon the upper border of the pancreas.
The Gastric Artery {Coronaria ventriculi), the smallest of the three branches
of the coeliac axis, passes upwards and to the left side, to the cardiac orifice of
the stomach, distributing branches to the oesophagus, which anastomose with the
aortic oesophageal arteries; others supply the cardiac end of the stomach, inoscu-
lating with branches of the splenic artery: it then passes from left to right, along
the lesser curvature of the stomach to the pylorus, lying in its course between
the layers of the lesser omentum, and giving branches to both surfaces of the
organ ; at its termination it anastomoses wnth the pyloric branch of the hepatic.
368,
ARTERIES.
The Hepatic Artery in the adult is intermediate in size between the gastric
and splenic; in the foetus, it is the largest of the three branches of the ccBliac
axis. It passes upwards to the right side, between the layers of the lesser
omentum, and in front of the foramen of Winslow, to the transverse fissure of the
liver, where it divides into two branches (right and left), which supply the cor-
responding lobes of that organ, accompanying the ramifications of the vena portae
and hepatic duct. The hepatic artery, in its course along the right border of the
lesser omentum, is in relation with the ductus communis choledocus and portal
vein, the former lying to the right of the artery, and the vena portae behind.
Its branches are the
Pyloric.
Gastro-duodenalis
Cystic.
The Pyloric Branch arises from the hepatic, above the pylorus, descends to
Gastro-epiploica dextra.
Pancreatico-duodenalis.
205. — The Coeliac Axis and its Branches, the Liver having been raised, and
the Lesser Omentum removed.
e a /t
the pyloric end of the stomach; and passes from right to left along its lesser curva-
ture, supplying it with branches, and inosculating with the gastric artery.
The Gastro-Duodenalis is a short but large branch, which descends behind
the duodenum, near the pylorus, and divides at the lower border of the stomach
into two branches, the gastro-epiploica dextra and the pancreatico-duodenalis.
BRANCHES OF CiELIAC AXIS.
367
Previous to its division, it gives off two or tliree small inferior pyloric branches
to the pyloric end of the stomach and pancreas.
The Gastro-Epiploica D extra runs from right to left along the greater curva-
ture of the stomach, between the layers of the great omentum, anastomosing about
the middle of the lower border of this organ with the gastro-epiploica sinistra
from the splenic artery. This vessel gives off numerous branches, some of which
ascend to supply both surfaces of the stomach, whilst others descend to supply
the great omentum.
The Pancreatico Duodenalis descends along the contiguous margins of the
duodenum and pancreas. It supplies both these organs, and anastomoses with
the inferior pancreatico-duodenal branch of the superior mesenteric artery.
In ulceration of the duodenum, which frequently occurs in connexion with
severe burns, this artery is often involved, and death may occur from sudden
hjemorrhage into the intestinal canal.
206. — The Cseliac Axis and its Branches, the Stomach having been raised, and
the Transverse Meso-Colon removed.
The Cystic Artery, usually a branch of the right hepatic, passe upwards and
forwards along the neck of the gall bladder, and divides into two branches, one of
which ramifies on its free surface, the other, between it and the substance of the
liver.
The Splenic Artery, in the adult, is the largest of the three branches of the
B B
370 ARTERIES.
cseliac axis, and is remarkable for the extreme tortuosity of its course. It passes
horizontally to the left side behind the upper border of the pancreas, accompanied
by the splenic vein, which lies below it; and on arriving near the spleen, divides
into branches, some of which enter the hilus of that organ to be distributed
to its structure, whilst others are distributed to the great end of the stomach.
The branches of this vessel are:
Pancreaticse parvee. Gastric (Vasa brevia).
Pancreatica magna. Gastro-epiploica sinistra.
The Pancreatic are numerous small branches derived from the splenic as it runs
behind the upper border of the pancreas, supplying its middle and left parts. One
of these, larger than the rest, is given off from the splenic near the left extremity
of the pancreas; it runs from left to right near the posterior surface of the gland
following the course of the pancreatic duct, and is called the pancreatica magna.
These vessels anastomose with the pancreatic branches of the pancreatico-duo-
denal arteries.
The Gastric ( Vasa brevia) consist of from five to seven small branches, which
arise either from the termination of the splenic artery, or from its terminal
branches; and passing fi'om left to right, between the layers of the gastro-splenic
omentum, are distributed to the great curvature of the stomach; anastomosing
with branches of the gastric and gastro-epiploica sinistra arteries.
The Gastro-Epiploica Sinistra, the largest branch of the splenic, runs from
left to right along the great curvature of the stomach, between the layers of the
great omentum; and anastomoses with the gastro-epiploica dextra. In its course,
it distributes several branches to the stomach, which ascend upon both surfaces;
others descend to supply the omentum.
Superior Mesenteric 'Artery.
In order to expose this vessel, raise the great omentum and transverse colon, draw down
the small intestines, and if the peritoneum is divided where the transverse meso-colon and
mesentery join, this artery will be exposed just as it issues beneath the lower border of the
pancreas.
The Superior Mesenteric Artery (fig. 207) supplies the whole length of the
small intestine, except the first part of the duodenum; it also supplies the caecum,
ascending and transverse colon; it is a vessel of large size arising from the fore part
of the aorta, about a quarter of an inch below the cseliac axis; being covered, at its
origin, by the splenic vein and pancreas. It passes forwards, between the pancreas
and transverse portion of the duodenum, crosses in front of this portion of the intes-
tine, and descends between the layers of the mesentery to the right iliac fossa, where
it terminates considerably diminished in size. In its course it forms an arch, the
convexity being directed forwards and downwards to the left side, the concavity
backwards and upwards to the right. It is accompanied by the superior mesen-
teric vein, and surrounded by the superior mesenteric plexus of nerves. Its
branches are the
Inferior pancreatico-duodenal. Ileo-colic.
Vasa intestini tenuis. Colica dextra.
Colica media.
The Inferior Pancreatico-Duodenal is given off from the superior mesenteric
below the pancreas, and is distributed to its right extremity and the transverse
and descending portions of the duodenum; anastomosing with the pancreatico-duo-
denal artery.
The Vasa Intestini Tenuis arise from the convex side of the superior mesente-
ric artery. They are usually from twelve to fifteen in number, and are distributed to
the jejunum and ileum. They run parallel with one another between the layers of
the mesentery; each vessel dividing into two branches, which unite with a similar
branch on each side, forming a series of arches, the convexities of which are
directed towards the intestine. From this first set of arches branches arise, which
again unite with similar branches from either side, and thus a second series of
SUPERIOR MESENTERIC.
371
arches is formed; and from these latter, a third, and even a fourth or fifth series
of arches are constituted, diminishing in size the nearer they approach the intes-
tine. From the terminal arches numerous small straight vessels arise which
encircle the intestine, upon which they are minutely distributed, ramifying between
its coats.
The Ileo-CoUc Artery is the lowest branch given off from the concavity of the
superior mesenteric artery. It descends between the layers of the mesentery to
the right iliac fossa, where it divides into two branches. Of these, the inferior
one inosculates with the lowest branches of the vasa intestini tenuis, from the con-
vexity of which branches proceed to supply the termination of the ileum, the
coecum and appendix coeci, and the ileo-coecal and ileo-colic valves. The superior
division inosculates with the colica dextra, and supplies the commencement of
the colon.
207. — The Superior Mesenteric Artery and its Branches.
The Colica Dextra arises from about the middle of the concavity of the supe-
rior mesenteric artery, and passing beneath the peritoneum to the middle of the
ascending colon, divides into two branches; a descending branch, which inoscu-
lates with the ileo-colic; and an ascending branch, which anastomoses with the
colica media. These branches form arches, from the convexity of which vessels
are distributed to the ascending colon. The branches of this vessel are covered
with peritoneum only on their anterior aspect.
B B 2
372
ARTERIES.
The Colica Media arises from the upper part of the concavity of the superior
mesenteric, and, passing forwards between the layers of the transverse meso-colon,
divides into two branches; the one on the right side inosculating with the colica
dextra; that on the left side, with the colica sinistra, a branch of the inferior
mesenteric. From the arches formed by their inosculation, branches are distributed
to the transverse colon. The branches of this vessel lie between two layers of
peritoneum.
208. — The Inferior Mesenteric Artery and its Branches.
XTiJe-Ttoi Ute/mor-rhottlul
Inferioe Mesenteric Artery.
In order to expose this vessel, draw the small intestines and mesentery over to the right
side of the abdomen, raise the transverse colon towards the thorax, and divide the perito-
neum covering the left side of the aorta.
The Inferior Mesenteric Artery (fig. 208) supplies the descending and sigmoid
flexure of the colon, and greater part of the rectum. It is smaller than the supe-
rior mesenteric; and arises from the left side of the aorta, between one and two inches
above its division into the common iliacs. It passes downwards to the left iliac
fossa, and then descends, between the layers of the meso-rectum, into the pelvis,
under the name of the superior hcemorrhoidal artery. It lies at first in close
relation with the left side of the aoi-ta, and then passes in front of the left common
iliac artery. Its branches are the
Colica sinistra. Sigmoidea.
Superior hasmorrhoidal.
INFERIOR MESENTERIC. 373
The Colica Sinistra passes behind the peritoneum, in front of the left kidney,
to reach the descending colon, and divides into two branches; an ascending branch,
which inosculates with the colica media; and a descending branch, which anasto-
moses with the sigmoid artery. From the arches formed by tliese inosculations,
branches are distributed to the descending colon.
The Sigmoid Artery runs obliquely downwards across the Psoas muscle to the
sigmoid flexure of the colon, and divides into branches which supply this part of
the intestine; anastomosing above, with the colica sinistra; and below, with the
superior haemorrhoidal artery. This vessel is sometimes replaced by three or four
small branches.
The Superior HcBmorrhoidal Artery, the continuation of the inferior mesen-
teric, descends into the pelvis between the layers of the meso-rectum, crossing, in
its course, the ureter, and left common iliac artery and vein. Opposite the middle
of the sacrum it divides into two branches, which descend one on each side of the
rectum, where they divide into several small branches, which are distributed
between the mucous and muscular coats of this tube, to near its lower end; ana-
stomosing with each other, with the middle hsemorrhoidal arteries, branches of
the internal iliac, and with the inferior hgemorrhoidal. branches of the internal
pudic.
The student should especially remark, that the trunk of this vessel descends
along the back part of the intestine as far as the middle of the sacrum before it
divides-; this is about a finger's length or four inches from the anus. In disease
of this tube, the rectum should never be divided beyond this point in that direction,
for fear of involving this artery.
The Supra-Renal Arteries are two small vessels which arise, one on each side
of the aorta, opposite the superior mesenteric artery. They pass obliquely up-
wards and outwards, to the under surface of the supra-renal capsules, to which
they are distributed, anastomosing with capsular branches from the phrenic
and renal arteries. In the adult these arteries are of small size; in the foetus
they are as large as the renal arteries.
The Renal Arteries are two large trunks, which arise from the sides of the
aorta, immediately below the superior mesenteric artery. Each is directed out-
wards, so as to form nearly a right angle with the aorta. The right one longer
than the left, on account of the position of the aorta, passes behind the inferior
vena cava. The left is somewhat higher than the right. Previously to entering
the kidney, each artery divides into four or five branches, which are distri-
buted to its substance. At the hilus, these branches lie between the renal vein
and ureter, the vein being usually in front, the ureter behind. Each vessel gives
off some small branches to the supra-renal capsules, the ureter, and to the sur-
rounding cellular membrane and muscles.
The Spermatic Arteries are distributed to the testes in the male, and to the
ovaria in the female. They are two small slender vessels, of considerable length,
which arise from the front of the aorta, a little below the renal arteries. Each
artery passes obliquely outwards and downwards, behind the peritoneum, cross-
ing the ureter, and resting on the Psoas muscle, the right spermatic lying
in front of the inferior vena cava, the left behind the sigmoid flexure of the
colon. On reaching the margin of the pelvis, each vessel passes in front of
the corresponding external iliac artery, and takes a diflferent course in the two
sexes.
In the Male, it is directed outwards, to the internal abdominal ring, and
accompanies the other constituents of the spermatic cord along the spermatic
canal to the testis, where it becomes tortuous, and divides into several branches,
two or three of which accompany the vas deferens, and supply the epididymis,
anastomosing with the deferential artery; others pierce the back part of the
tunica albuginea, and supply the substance of the testis.
In the Female, the spermatic arteries (ovarian) are shorter than in the male,
and do not pass out of the abdominal cavity. On arriving at the margins of the
374 ARTERIES.
pelvis, they pass inwards, between the two laminae of the broad ligament of the
uterus, to be distributed to the ovaries. One or two small branches supply the
Fallopian tubes; another passes on to the side of the uterus, and anastomoses with
the uterine arteries. Other offsets are continued along the round ligament,
through the inguinal canal, to the integument of the labium and groin. At an
early period of fcetal life, when the testes lie by the side of the spine, below
the kidneys, the spermatic arteries are short; but as these organs descend from
the abdomen into the scrotum, they become gradually lengthened.
The Phrenic Arteries are two small vessels, which present much variety in their
origin. They may arise separately from the front of the aorta, immediately below
the cseliac axis, or by a common trunk, which may spring either from the aorta,
or from the caeliac axis. Sometimes one is derived from the aorta, and the other
from one of the renal arteries. In only one out' of thirty-six cases, did these
arteries arise as two separate vessels from the aorta. They diverge from one another
across the crura of the Diaphragm, and then pass obliquely upwards and outwards
upon its under surface. The left phrenic passes behind the oesophagus, and runs
forwards on the left side of the oesophageal opening. The right phrenic, passing
behind the liver and inferior vena cava, ascends along the right side of the aper-
ture for transmitting that vein. Near the back part of the central tendon, each
vessel divides into two branches. The internal branch runs forwards to the ante-
rior margin of the thorax, supplying the Diaphragm, and anastomosing with its
fellow of the opposite side, and with the musculo-phrenic, a branch of the
internal, mammary. The external branch passes towards the side of the thorax,
and inosculates with the intercostal arteries. The internal branch of the right
phrenic gives off a few vessels to the inferior vena cava; and the left one some
branches to the oesophagus. Each vessel also' sends capsular branches to the
supra-renal capsule of its own side. The spleen on the left side, and the liver
on the right, also receive a few branches from these vessels.
The Lumbar Arteries are analogous to the intercostal. They are usually four
in number on each side, and arise from the back part of the aorta, nearly at right
angles with that vessel. They pass outwards and backwards, around the sides of
the body of the corresponding lumbar vertebra, behind the sympathetic nerve
and the Psoas muscle; those on the right side being covered by the vena cava,
and the two upper ones on each side by the crura of the Diaphragm. In the
interval between the transverse processes of the vertebrae, each artery divides
into a dorsal and an abdominal branch.
The dorsal branch gives off, immediately after its origin, a spinal branch,
which enters the spinal canal; it then continues its course backwards, between
the transverse processes, and is distributed to the muscles and integument of the
back, anastomosing with each other, and with the posterior branches of the inter-
costal arteries.
The spinal branch, besides supplying offsets which run along the nerves to
the dura mater and cauda equina, anastomosing with the other spinal arteries,
divides into two branches, one of which ascends on the posterior surface of the
body of the vertebra above, and the other descends on the posterior surface of
the body of the vertebra below, both vessels anastomosing with similar branches
from neighbouring spinal arteries. The inosculations of these vessels on each
side, throughout the whole length of the spine, form a series of arterial arches
behind the bodies of the vertebrje, which are connected with each other, and with
a median longitudinal vessel, extending along the centre of the bodies of the ver-
tebrae, by transverse branches. From these vessels offsets are distributed to the
periosteum and bones.
The abdominal branches pass outwards, behind the quadratus Imuborum, the
lowest branch occasionally in front of that muscle, and, being continued between
the abdominal muscles, anastomose with branches of the epigastric and internal
mammary in front, the intercostals above, and those of the ilio-lumbar, and
circumflex iliac, beloic.
COMMON ILIAC.
375
The Middle Sacral Artery is a small vessel, about the size of a crow-quill
which arises from the posterior part of the aorta, just at its bifurcation. It
descends upon the last lumbar vertebra, and along the middle line of the anterior
surface of the sacrum, to the upper part of the coccyx, where it terminates
by anastomosing with the lateral sacral arteries. From it branches arise
which run through the meso-rectum, to supply the posterior surface of the
rectum. Other branches are given off on each side, which anastomose with the
lateral sacral arteries, and send off small offsets which enter the anterior sacral
foramina.
Common Iliac ARXEPaEs.
The abdominal aorta terminates by dividing into the two common iliac arteries.
The bifurcation of this vessel usually takes place on the left side of the body of
the fourth lumbar vertebra. This point corresponds to the left side of the umbili-
cus, and is on a level with a line drawn across from one crista-ilii to the other.
The common iliac arteries are about two inches in length; diverging from the
209. — Arteries of the Pelvis.
termination of the aorta, they pass downwards and outwards to the margin of the
pelvis, and divide opposite the intervertebral substance, between the last lum-
bar vertebra and the sacrum, into two branches, the external and internal iliac
376 ARTERIES.
arteries; the former supplying the lower extremity, the latter the viscera and
parietes of the pelvis.
The Right Common Iliac is somewhat longer than the left, and passes more
obliquely across the body of the last lumbar vertebra. It is covered in front by
the peritoneum, the intestines, the branches of the sympathetic nerve, and crossed,
at its point of division, by the ureter. Behind, it is separated from the last
lumbar vertebra by the two common iliac veins. On its outer side it is in relation
with the vena cava, and right common iliac vein above, and the Psoas magnus
muscle below.
The Left Common Iliac is in relation in front with the peritoneum, branches of
the sympathetic nerve, the rectum and superior hasmorrhoidal artery, and crossed,
at its point of bifurcation, by the ureter. The left common iliac vein lies partly
on the inner side, and part beneath the artery; on iis outer side, it is in relation
with the Psoas magnus.
Branches. The common iliac arteries give off small branches to the perito-
neum, Psose muscles, ureters, and to the surrounding cellular membrane, and
occasionally give origin to the ilio-lumbar, or renal arteries.
Peculiarities. Its point of origin varies according to the bifurcation of the aorta. In
three-fourths of a large number of cases, the aorta bifurcated either upon the fourth
lumbar vertebra, or upon the inter-vertebral disc, between it and the fifth ; one case in nine
being below, and one in eleven above this point. In tea out of every thirteen cases, the
vessel bifurcated within half an inch above or below the level of the crest of the Hium ;
more fiequently below than above.
The point of division is subject to great variety. In two-thirds of a large number of
cases, it was between the last lumbar vertebra and the upper border of the sacrum ; in
one case in eight being above, and in one in six below that point. The left common iliac
artery divides lower down more frequently than the right.
The relative length, also, of the two common iliac arteries varies. The right common
iliac was longest in sixty-thi-ee cases ; the left, in fifty-two ; -whilst they were both equal in
fifty-three. The length of the arteries varied in five-sevenths of the cases examined, from
an inch and a-half to three inches ; in about half of the remaining cases, the artery was
longer; and in the other half, shorter ; the minimum length being less than half an inch,
the maximum, four and a-half inches. In one instance, the right common iliac was found
wanting, the external and internal iliacs arising directly from the aorta.
Surgical Anatomy. The application of a ligature to the common iliac artery may be re-
quired on account of aneurism or hsemorrhage, implicating the external or internal iliacs,
or on account of secondary haemorrhage after amputation of the thigh high up. It has been
seen that the commencement of this vessel corresponds to the left side of the umbilicus
on a level with a line drawn from the highest point of one iliac crest to the opposite one,
and its course to a line extending from this point downwards towards the middle of Pou-
part's ligament. The line of incision required in the first steps of an operation for securing
this vessel, would materially depend upon the nature of the disease. If the surgeon select
the iliac region, a curved incision, about five inches in length, may be made, commencing
on the left side of the umbilicus, carried outwards towards the anterior superior iliac spine,
and then along the upper border of Poupart's ligament, as far as its middle. But if the
aueurismal tumour should extend high up in the abdomen, along the external iliac, it is
better to select the side of the abdomen, approaching the artery from above, by making
an incision from four to five inches in length, from about two inches above and to the left
of the umbilicus, carried outwards in a curved direction towards the lumbar region, and
terminating a little below the anterior superior ihac spine. The abdominal muscles (in
either case) having been cautiously divided in succession, the transversalis fascia must be
carefully cut through, and the peritoneum, together with the ureter, separated from it and
from the iliac fascia, and pushed aside ; the sacro-iliac articulation must be felt for, and upon
it the vessel will be felt pulsating, and may be fully exposed in close connection with its
accompanying vein. On the right side, both common iliac veins, as well as the inferior vena
cava, are in close connection with the artery, and must be carefully avoided. On the left side,
the vein usually lies on the inner side, and behind the artery ; but it occasionally happens
that the two common iliac veins are joined on the left instead of the right side, which
would add much to the diSiculty of an operation in such a case. If the common ihac ar-
tery is so short that danger is to be apprehended from secondary hsemorrhage if a ligature
is applied to it, it would be preferable, in such a case, to tie both the external and internal
iliac near their orighi. This operation has been performed in several instances ; in a few
with success.
INTERNAL ILIAC. 377
Internal Iliac Artery.
The internal iliac artery supplies the walls and viscera of the pelvic cavity,
the generative organs, and inner side of the thigh. It is a short, thick vessel,
smaller than the external iliac, and about an inch and a-half in length, which
arises at the point of bifurcation of the common iliac; and, passing downwards to
the upper margin of the great sacro-sciatic foramen, divides into two large trunks,
an anterior, and posterior; a partially obliterated cord, the hypogastric artery,
extending from the extremity of the vessel forwards to the bladder.
Relations. In front, with the ureter, which separates it from the peritoneum.
Behind, it is in relation with the internal iliac vein, the lumbo-sacral nerve, and
Pyriformis muscle. By its outer side, near its origin, with the Psoas muscle.
Plan of the Relations of the Internal Iliac Artery.
In front.
Peritoneum,
Ureter.
Outer side.
Psoas magnus.
Behind.
Internal iliac vein.
Lumbo-sacral nerve.
Pyriformis muscle.
In the foetus, the internal iliac artery (hypogastric), is twice as large as the ex-
ternal iliac, and appears the continuation of the common iliac. Passing forwards
to the bladder, it ascends along the side of this viscus to its apex, to which it
gives branches (superior vesical); it then passes upwards along the posterior part
of the abdomen to the umbilicus, converging towards its fellow of the opposite
side. Having passed through the umbilical opening, the two arteries twine around
the umbilical vein, forming with it the umbilical cord; and, ultimately, ramify in
the substance of the placenta. That portion of the vessel placed within the ab-
domen, is called the hypogastric artery; and that external to that cavity, the
umbilical artery.
At birth, when the placental circulation ceases, that portion of the hypogastric
artery which extends from the umbilicus to the apex of the bladder, contracts,
and ultimately dwindles to a solid fibrous cord; the portion of the same vessel
extending from the apex of the bladder to within an inch and a-half of its origin,
is not totally impervious, though it becomes considerably reduced in size; and
serves to convey blood to the bladder, under the name of the superior vesical
artery.
Peculiarities, as regards its length. In two-thirds of a large number of cases, the length
of the internal iliac varied between an inch and an inch and a-half; in the remaining third,
it was more frequently longer than shorter, the maximum length being three inches, the
minimum, half an inch.
The lengths of the common and internal iliac arteries bear an inverse proportion to each
other, the internal iliac artery being long when the common iliac is short, and vice versa.
As regards its place of division. The place of division of the internal iliac varies between
the upper margin of the sacrum, and the upper border of the sacro-sciatic foramen.
The arteries of the two sides in a series of cases often differed in length, but neither
seemed constantly to exceed the other.
Surgical Anatomy. The application of a ligature to the internal iliac artery may be re-
quired in cases of aneurism or hsemorrhage affecting one of its branches. This vessel may
be secured by making an incision through the abdominal parieties in the iliac region, in a
direction and to an extent similar to that for securing the common iliac ; the transversaUs
fascia having been cautiously divided, and the peritoneum pushed inwards from the
378 ARTERIES.
iliac fossa towards the pelvis, the finger may feel the pulsation of the external iliac at the
bottom of the wound ; and, by tracing this vessel upwards, the internal iliac is arrived at,
opposite the sacro-iliac articulation. It should be remembered that the vein lies behind,
and on the right side a little external to the artery, and in close contact with it ; the ureter
and peritoneum, which lie in front, must also be avoided. The degree of facility in applying
a ligature to this vessel, will mainly depend upon its length. It has been seen that, in the
great majority of the cases examined, the artery was short, varying from an inch to an inch
and a-half ; in these cases, the artery is deej)ly seated in the pelvis ; when, on the contrary,
the vessel is longer, it is found partly above that cavity. If the artery is very short, which
occasionally happens, it would be preferable to apply a ligature to the common iliac, or
upon the external and internal iliacs at their origin.
Branches of the Internal Iliac.
From the Anterior Trunk. From the Posterior Trunk.
Superior vesical. Gluteal,
Inferior vesical. Ileo-lumbar.
Middle hEemorrhoidal. Lateral sacral.
Obturator.
Internal pudic.
Sciatic.
-r J, , ( Uterine.
In female. \ ^^ . ,
-' I Vaginal.
The Superior Vesical is that part of the foetal hypogastric artery which remains
pervious after birth. It extends to the side of the bladder, distributing numerous
branches to the body and fundus of this organ. From one of these, a slender
vessel is derived which accompanies the vas deferens in its course to the testis,
•where it anastomoses with the spermatic artery. This is the artery of the vas
deferens. Other branches supply the ureter.
The Middle Vesical, usually a branch of the superior, is distributed to the base
of the bladder, and under surface of the vesiculse seminales.
The Inferior Vesical arises from the anterior division of the internal iliac,
in common with the middle hemorrhoidal, and is distributed to the base of the
bladder, the prostate gland, and vesiculse seminales. Those branches distributed
to the prostate, communicate with the corresponding vessel of the opposite side.
The Middle ffcemorrhoidal Artery usually arises together with the preceding
vessel. It supplies the rectum, anastomosing with the other hagmorrhoidal
arteries.
The Uterine Artery passes downwards from the anterior trunk of the internal
iliac to the neck of the uterus. Ascending, in a tortuous course, on the side of
this viscus, between the layers of the broad ligament, it distributes branches to
its substance, anastomosing, near its termination, with a branch from the ovarian
artery. Branches from this vessel are also distributed to the bladder and ureter.
The Vaginal Artery is analogous to the inferior vesical in the male; it descends
upon the vagina, supplying its mucous membrane, and sending branches to the
neck of the bladder, and contiguous part of the rectum.
The Obturator Artery usually arises from the anterior trunk of the internal
iliac, frequently from the posterior. It passes forwards below the brim of the
pelvis, to the groove in the upper border of the obturator foramen, and escaping
from the pelvic cavity through this aperture, divides into an internal and an ex-
ternal branch. In the pelvic cavity, this vessel lies upon the pelvic fascia, beneath
the peritoneum, and a little below the obturator nerve. And whilst passing
through the obturator foramen, is contained in an oblique canal, formed by the
horizontal branch of the pubes, above, and the arched border of the obturator
membrane, below.
Braiiches. Within the pelvis, the obturator artery gives oif an iliac branch to
the iliac fossa, which supplies the bone and the Iliacus muscle, and anastomoses
with the ilio-lumbar artery; a vesical branch which runs backwards to supply
the bladder; and 2k pubic branch, which is given off from the vessel just before it
OBTUKATOR, INTERNAL PUDIC. 379
leaves the pelvic cavity. It ascends upon the back of the pubes, commu-
nicating with oiFsets from the epigastric artery, and with the corresponding vessel
of the opposite side. This branch is placed on the inner side of the femoral ring.
External to the pelvis, the obturator artery divides into an external and an inter-
nal branch, which are deeply situated beneath the External obturator muscle,
skirting the circumference of the obturator foramen, and anastomosing at the
lower part of this aperture with each other, and with branches of the internal
circumflex artery.
The internal branch curves inwards along the inner margin of the obturator
foramen, distributing branches to the Obturator muscles, Pectineus, Adductors,
and Gracilis, and anastomoses with the external branch, and with the internal cir-
cumflex artery.
The external branch curves around the outer margin of the foramen, to the
space between the Gemellus inferior and Quadratus femoris, where it anastomoses
with the sciatic artery. It supplies the Obturator muscles, anastomoses, as it
passes backwards, with the internal circumflex, and sends a branch to the hip-
joint through the cotyloid notch, which ramifies on the round ligament as far as
the head of the femur.
Peculiarities. Li two out of every three cases this vessel arises from the internal iliac.
In one case in 3I from the epigastric; and in about one in seventy-two cases by two roots
from both vessels. It arises in about the same proportion from the external iliac artery.
The origin of the obturator from the epigastric is not commonly found on both sides of the
same body.
When the obturator artery arises at the front of the pelvis from the epigastric, it descends
almost vertically downwards to the upjper part of the obturator foramen. The artery in
this course usually descends in contact with the external ihac vein, and lies on the outer
side of the femoral ring; in such cases it would not be endangered in the operation for
femoral hernia. Occasionally, however, it curves inwards along the free margin of Gim-
bernat's ligament, and inider such circumstances it would almoj^t completely encircle the
neck of a hernial sac (supposing a hernia to exist in such a case), and would be in great
danger of being wounded if an operation was necessary.
The Internal Pudic is the smaller of the two terminal branches of the anterior
trunk of the internal iliac, and supplies the external organs of generation. It passes
downwards and outwards to the lower border of the great sacro-sciatic foramen,
and emerges from the pelvis between the Pyriformis and Coccygeus muscles; it
then crosses the spine of the ischium, and enters that cavity through the lesser
sacro-sciatic foramen. The artery now crosses the Internal obturator muscle, to
the ramus of the ischium, being covered by the obturator fascia, and situated
about an inch and a half from the margin of the tuberosity; it then ascends for-
wards and upwards along the ramus of the ischium, pierces the posterior layer of
the deep perinseal fascia, and runs forwards along the inner margin of the ramus
of the pubes; finally it perforates the anterior layer of the deep perinseal fascia,
and divides into its two terminal branches, the dorsal artery of the penis, and the
artery of the corpus cavernosum.
Relations. In the first part of its course, within the pelvis, it lies in front of the
Pyriformis muscle and sacral plexus of nerves, and on the outer side of the rec-
tum (on the left side). As it crosses the spine of the ischium, it is covered by
the Gluteus maximus, and great sacro-sciatic ligament. And when it enters the
pelvis, it lies on the outer side of the ischio-rectal fossa, upon the surface of the
Obturator internus muscle, contained in a fibrous canal formed by the obturator
fascia and the falciform process of the great sacro-sciatic ligament. It is accom-
panied by the pudic veins, and the internal pudic nerve.
Peculiarities. The internal pudic is sometimes smaller than usual, or fails to give off one
or two of its usual branches ; in such cases, the deficiency is supplied by branches derived
from an additional vessel, the accessory pudic, which generally arises from the pudic artery
before its exit from tlie great sacro-sciatic foramen, and passes forwards near the
base of the bladder, on the upper part of the prostate gland, to the perinasum,
where it gives off those branches usually derived from the pudic artery itself The deh-
380 ARTERIES.
ciency most frequently met with, is that in which the internal pudic ends as the artery of
the bulb ; the artery of the corpus cavernosum and arteria dorsalis penis being derived
from the accessory pudic. Or the pudic may terminate as the superficial perinseal, the
artery of the bulb being derived, with the other two branches, from the accessory vessel.
The relation of the accessory pudic to the prostate gland and urethra, is of the greatest
interest in a surgical point of view, as this vessel is in danger of being wounded in the
lateral operation of lithotomy.
Branches. Within the pelvis, the internal pudic gives off sef veral small branches,
which supply the muscles, sacral nerves, and viscera in this cavity. In the
perinceum the following branches are given off.
Inferior or external hsemorrhoidal. Artery of the bulb.
Superficial perin^eal. Artery of the corpus cavernosum.
Transverse peringeal. Dorsal artery of the penis.
The External Hcemorrhoidal are two or three small arteries, which arise from
the internal pudic as it passes above the tuberosity of the ischium. Crossing the
ischio-rectal fossa, they are distributed to the muscles and integument of the anal
region.
The Superficial Perinceal Artery supplies the scrotum, and muscles and integu-
ment of the perinaeum. It arises from the internal pudic, in front of the preceding
branches, and piercing the lower border of the deep perinaeal fascia, runs across
the Transversus perinaei, and through the triangular space between the Accelerator
urinse and Erector penis, both of which it supplies, and is finally distributed to the
skin of the scrotum and dartos. In its passage through the perinasum it lies
beneath the superficial perinasal fascia.
The Transverse Perinceal is a small branch which arises either from the inter-
nal pudic, or from the superficial perina3al artery as it crosses the Transversus
perin^ei muscle. Piercing the lower border of the deep perinaeal fascia, it runs
transversely inwards along the cutaneous surface of the Transversus perinsei muscle,
which it supplies, as well as the structures between the anus and bulb of the
urethra.
The Artery of the Bulb is a large but very short vessel, arising from the inter-
nal pudic between the two layers of the deep perinasal fascia, and passing nearly
transversely inwards, pierces the bulb of the urethra, in which it ramifies. It
gives off a small branch which descends to supply Cowper's gland. This artery
is of considerable importance in a surgical point of view, as it is in danger of
being wounded in the lateral operation of lithotomy, an accident usually attended
with severe and alai-ming haemorrhage. This vessel is sometimes very small,
occasionally wanting, or even double. It sometimes arises from the internal pudic
earlier than usual, and crosse.s the perinaeum to reach the back part of the bulb.
In such a case the vessel could hardly fail to be wounded in the performance of
the lateral operation for lithotomy. If, on the contrary, it should arise from an
accessory pudic, it lies more forward than usual, and is out of danger in the ope-
ration.
The Artery of the Corpxis Cavernosum, one of the terminal branches of the
internal pudic, arises from that vessel while it is situated between the crus penis
and the ramus of the pubes; piercing the crus penis obliquely, it runs forwards in
the corpus cavernosum by the side of the septum pectiniforme, to which its
branches are distributed.
The Dorsal Artery of the Penis ascends between the crus and pubic symphysis,
and piercing the suspensory ligament, runs forwards on the dorsum of the penis to
the glans, where it divides into two branches, which supply the glans and prepuce.
On the dorsum of the penis, it lies immediately beneath the integument, parallel
with the dorsal vein and corresponding artery of the opposite side. It supplies
the integument and fibrous sheath of the corpus cavernosum.
The Internal Pudic Artery in the Female, is smaller than in the male. Its
origin and course are similar, and there is considerable analogy in the distribution
SCIATIC.
381
of its branches. The superficial artery supplies the labia pudenda; the artery of
the bulb supplies the erectile tissue of the bulb of the vagina, whilst the two ter-
minal branches supply the clitoris; the artery of the corpus cavernosum, the
cavernous body of the clitoris; and the arteria dorsalis clitoridis, the dorsum of
that orsran.
a 10.— The Arteries of the Gluteal and Posterior Femoral
Regions.
The Sciatic Artery (fig.
2 1 o), the larger of the two
terminal branches of the
anterior trunk of the in-
ternal iliac, is distributed
to the muscles on the back
of the pelvis. It passes
downwards to the lower
part of the great sacro-
sciatic foramen, behind the
internal pudic, resting on
the sacral plexus of nerves
and Pyriformis muscle, and
escapes from the pelvis be-
tween the Pyriformis and
Coccygeus. It then de-
scends in the interval
between the Trochanter
major and tuberosity of the
ischium, accompanied by
the sciatic nerves, and
covered in by the Gluteus
maximus, and divides into
branches, which supply the
deep muscles at the back
of the hip.
Within the pelvis it dis-
tributes branches to the
Pyriformis, Coccygeus, and
Levator ani muscles; some
hgemorrhoidal branches,
which supply the rectum,
and occasionally take the
place of the middle haemor-
rhoidal artery; and vesical
branches to the base and
neck of the bladder, vesi-
culse seminales, and pros-
tate gland. External to the
pelvis it gives off the coccy-
geal, inferior gluteal, comes
nervi ischiadici, muscular,
and articular branches.
The Coccygeal Branch
runs inwards, pierces the
great sacro-sciatic liga-
ment, and supplies the
Gluteus maximus, the integument, and other structures on the posterior surface of
the coccyx.
The Inferior Gluteal Branches, three or four in number, supply the Gluteus
maximus muscle.
The Comes Nervi Ischiadici is a long slender vessel, which accompanies the
Sajj/T T/n ternaZ A r^traJan.
382 ARTERIES.
great sciatic nerve for a short distance; it then penetrates it, and runs in its sub-
stance to the lower part of the thigh.
The Muscular Branches supply the muscles on the back part of the hip, anas-
tomosing with the gluteal, internal and external circumflex, and superior perfo-
rating arteries.
Some articular branches are also distributed to the capsule of the hip-joint.
The Gluteal Artery is the largest branch of the internal iliac, and appears to
be the continuation of the posterior division of that vessel. It is a short thick
trunk, which passes downwards to the upper part of the great sacro-sciatic
foramen, escapes from the pelvis above the upper border of the Pjriformis muscle,
and immediately divides into a superficial and deep branch. Within the pelvis, it
gives off a few muscular branches to the Iliacus, Pyriformis, and Obturator
internus, and just previous to quitting that cavity a nutritious artery, which enters
the ilium.
The superficial branch passes beneath the Gluteus maximus, and divides into
numerous branches, some of which supply this muscle, whilst others perforate its
tendinous origin, and supply the integument of the posterior surface and side
of the sacrum, anastomosing with the posterior branches of the sacral arteries.
The deep branch runs between the Gluteus medius and minimus, and subdi-
vides into two. Of these, the superior division, continuing the original course of
the vessel, passes along the upper border of the Gluteus minimus to the anterior
superior spine of the ilium, anastomosing with the circumflex iliac and ascending
branches of the external circumflex artery. The inferior division crosses the
Gluteus minimus obliquely to the Trochanter major, distributing branches to the
Glutei muscles, and inosculates with the external circumflex artery. Some branches
pierce the Gluteus minimus to supply the hip-joint.
The Ilio-Lumbar Artery ascends beneath the Psoas muscle and external iliac
vessels, to the upper part of the iliac fossa, where it divides into a lumbar and an
iliac branch.
The lumbar branch supplies the Psoas and Quadratus lumborum muscles, anas-
tomosing with the last lumbar artery, and sends a small spinal branch through
the intervertebral foramen, between the last lumbar vertebra and the sacrum,
into the spinal canal, to supply the spinal cord and its membranes.
The iliac branch descends to supply the Iliacus internus, some offsets running
between the muscle and the bone, one of which enters an oblique canal to supply
the diploe, whilst others run along the crest of the ilium, distributing branches to
the Gluteal and Abdominal muscles, and anastomosing in their course with the
gluteal, circumflexa ilii, external circumflex, and epigastric arteries.
The Lateral Sacral Arteries are usually two in number on each side, superior
and inferior.
The superior, which is of large size, passes inwards, and after anastomosing with
branches from the middle sacral, enters the first or second sacral foramen, is dis-
tributed to the contents of the sacral canal, and escaping by the corresponding
posterior sacral foramen, supplies the skin and muscles on the dorsum of the sacrum.
The inferior branch passes obliquely across the front of the Pyriformis muscle
and sacral nerves to the inner side of the anterior sacral foramina, descends
on the front of the sacrum, and anastomoses over the coccyx with the sacra-media
and opposite lateral sacral arteries. In its course, it gives off branches, which
enter the anterior sacral foramina, these after supplying the bones and membranes
of the interior of the spinal canal, escape by the posterior sacral foramina, and are
distributed to the muscles and skin on the dorsal surface of the sacrum.
External Iliac Artery.
The external iliac artery is the chief vessel which supplies the lower limb. It
is larger in the adult than the internal iliac, and passes obliquely downwards and
outwards along the inner border of the Psoas muscle, from the bifurcation of the
common iliac to the femoral arch, where it enters the thigh, and becomes the
EXTERNAL ILIAC. 383
femoral artery. The course of this vessel would be indicated by a line drawn
from the left side of the umbilicus to a point midway between the anterior superior
spinous process of the ilium and the symphysis pubis.
Relations. In front, with the peritoneum, sub-peritoneal areolar tissue, the
intestines, and a thin layer of fascia, derived from the iliac fascia, which surrounds
the artery and vein. At its origin it is occasionally crossed by the ureter. The
spermatic vessels descend for some distance upon it near its termination, and it is
crossed in this situation by a branch of the genito-crural nerve and the circumflexa
illi vein ; the vas deferens curves down along its inner side. Behind, it is in rela-
tion with the external iliac vein, which, at the femoral arch, lies at its inner side;
on the left side the vein is altogether internal to the artery. Externally, it rests
against the Psoas muscle, from which it is separated by the iliac fascia. The
artery rests upon this muscle near Poupart's ligament. Numerous lymphatic
vessels and glands are found lying on the front and inner side of the vessel.
Plan of the Relations of the External Iliac Artery.
^ In front.
Peritoneum, intestines, and iliac fascia.
-VT C Spermatic vessels.
JNear \ rc -i. ^
-n J.) ) (ienito-crural nerve.
Jroupart s < ^- n •^■■
-r . \ ■(■ ) (Ju'cumnesa liu vein.
° ^ ■ ( Lymphatic vessels and glands.
Psoas magnus. \\is,G External iliac vein and vas deferens
• Ihac fascia. \ ' / at femoral arch.
Behind.
External iliac vein.
Surgical Anatomy. The application of a ligature to the external iliac may be required in
cases of aneurism of the femoral artery, or in cases of secondary haemorrhage, after the
latter vessel has been tied for popliteal aneurism. This vessel may be secured in any
part of its course, excepting near its upper end, on account of the circulation through,
the internal iliac, and near its lower end, on account of the origin of the epigastric and
circumflex vessels. One of the chief points in the performance of the operation is to
secure the vessel without injury to the peritoneum. The patient having been placed in
the recumbent position, an incision should be made, commencing about an inch above
and to the inner side of the anterior superior spinous process of the ilium, and running
downwards and outwards to the outer end of Poupart's ligament, and parallel with its
outer half, to a little above its middle. The abdominal muscles and transversalis fascia
having been cautiously divided, the peritoneum should be separated from the iliac fossa
and pushed towards the pelvis ; and on introducing the finger to the bottom of the wound
the artery may be felt pulsating along the inner border of the Psoas muscle. The external
ihac vein is situated along the inner side of the artery, and must be cautiously separated
from it by the finger-nail, or point of the knife, and the aneurism needle should be intro-
duced on the inner side, between the artery and vein.
Branches. Besides several small branches to the Psoas muscle and the neigh-
bouring lymphatic glands, the external iliac gives off two branches of considerable
size, the
Epigastric. Circumflexa ilii.
The Epigastric Artery arises from the external iliac, a few lines above Poupart's
ligament. It at first descends to reach this ligament, and then ascends obliquely
upwards and inwards between the peritoneum and transversalis fascia, to the
margin of the sheath of the Rectus muscle. Having perforated the sheath near
its lower third, it ascends vertically upwards behind the Rectus, to which it is
distributed, dividing into numerous branches, which anastomose above the umbi-
licus with the terminal branches of the internal mammary and inferior intercostal
arteries. It is accompanied by two veins, which usually unite into a single trunk
before their termination in the external iliac vein.. As this artery ascends from Pou-
part's ligament to the Rectus, it lies behind the inguinal canal, to the inner side
384 ARTERIES.
of the internal abdominal ring, and immediately above the femoral ring, the vas
deferens in the male, and the round ligament in the female, crossing behind the
artery in descending into the pelvis.
Branches. The branches of this vessel are the cremasteric, which accompanies
the spermatic cord, and supplies the Cremaster muscle, anastomosing with the
spermatic artery. A pubic branch, which runs across Poupart's ligament, and then
descends behind the pubes to the inner side of the crural ring, and anastomoses
with offsets from the obturator artery. Muscular branches, some of which are
distributed to the abdominal muscles and peritoneum, anastomosing with the
lumbar and circumflexa ilii arteries; others perforate the tendon of the external
Oblique and supply the integument, anastomosing with branches of the external
epigastric.
Peculiarities. The origin of the epigastric may take plate from any part of the external
iliac between Poupart's ligament and two inches and a half above it ; or it may arise below
this ligament, from the femoral, or from the deep femoral.
Union with Branches. It frequently arises from the external iliac by a common trunk
with the obturator. Sometimes the epigastric arises from the obturator, the latter vessel
being furnished by the internal iliac, or the epigastric may be formed of two branches, one
derived from the external iliac, the other from the internal iliac.
The Circumflex Iliac Artery arises from the outer side of the external iliac,
nearly opposite the epigastric artery. It ascends obliquely outwards behind
Poupart's ligament, and runs along the inner surface of the crest of the ilium to
about its middle, where it pierces the Transversalis, and runs backwards between
this muscle and the Internal oblique, to anastomose with the ilio-lumbar and
gluteal arteries. Opposite the anterior superior spine of the ilium, it gives off a
large branch, which ascends between the Internal oblique and Transversalis
muscles, supplying them and anastomosing with the lumbar and epigastric arteries.
The circumflex iliac artery is accompanied by two veins, which, uniting into a
single trunk, ci'osses the external iliac artery just above Poupart's ligament, and
enters the external iliac vein.
Femoral Artery.
The femoral artery is the continuation of the external iliac. It commences
immediately beneath Poupart's ligament, midway between the anterior superior
spine of the ilium and the symphysis pubis, and passing down the fore part and
inner side of the thigh, terminates at the opening in the Adductor magnus, at the
junction of the middle with the lower third of the thigh, where it becomes the
popliteal artery. A line drawn from a point midway between the anterior supe-
rior spine of the ilium and the symphysis of the pubes to the inner side of the
internal condyle of the femur, will be nearly parallel with the course of this
artery.' This vessel, at the upper part of the thigh, lies a little internal
to the head of the femur; in the lower part of its course, on the inner side of
the shaft of this bone, and between these two points the vessel is separated from
the bone by a considerable interval.
In the upper third of the thigh the femoral artery is very superficial, being
covered by the integument, inguinal glands, and by the superficial and deep fascias,
and is contained in a triangular space, called ' Scarpa's triangle.'
Scarpa's Triangle. Scarpa's triangle corresponds to the depression seen imme-
diately below the fold of the groin. It is a triangular space, the apex of which
is directed downwards, and the sides of which are formed externally by the Sar-
torius, internally by the Adductor longus, and the base, by Poupart's ligament. The
floor of this space is formed from without inwards by the Iliacus, Psoas, Pectineus,
Adductor longus, and a small part of the Adductor brevis muscles; and it is
divided into two nearly equal parts by the femoral artery and vein, which extend
from the middle of its base to its apex: the artery giving off in this situation its
cutaneous and profunda branches, the vein receiving the deep femoral and internal
saphena veins. In this space, the femoral artery rests on the inner margin of the
FEMORAL.
385
Psoas muscle, which separates it from the capsular ligament of the hip-joint.
The artery in this situation is crossed in front by the crural branch of the genito-
crural nerve, and behind by the branch to the Pectineus from the anterior crural.
The femoral vein lies at
its inner side, between the 21 1.— Surgical Anatomy of the Femoral Artery.
margins of the Pectineus
and Psoas muscles. The
anterior crural nerve lies
about half an inch to the
outer side of the femoral
artery, deeply imbedded
between the Iliacus and
Psoas muscles; and on the
Iliacus muscle, internal to
the anterior superior spi-
nous process of the ilium,
is the external cutaneous
nerve. The femoral artery
and vein are enclosed in a
strong fibrous sheath, form-
ed by fibrous and cellular
tissue, and by a process of
fascia sent inwards from
the fascia lata; the vessels
are separated, however,
from one another by thin
fibrous partitions.
In the middle third of
the thigh, the femoral ar-
tery is more deeply seated,
being covered by the in-
tegument, the superficial
and deep fasciae, and the
Sartorius, and is contained
in an aponeurotic canal;
formed by a dense fibrous
band, which extends trans-
versely from the Vastus
internus to the tendons of
the Adductor longus and
magnus muscles. In this
part of its course it lies
in a depression, bounded
externally by the Vastus
internus, internally by the
Adductor longus and Ad-
ductor magnus. The fe-
moral vein lies on the
outer side of the artery,
in close apposition with it,
and, still more externally,
is the internal (long) saphenous nerve.
Relations. From above downwards, the femoral artery rests upon the Psoas
muscle, which separates it from the margin of the pelvis and capsular ligament
of the hip; it is next separated from the Pectineus, by the profunda vessels and
femoral vein; it then lies upon the Adductor longus; and lastly, upon the tendon
of the Adductor magnus, the femoral vein being interposed. To its inner side,
c c
J^Vaff-n^
Super. SxternaX Arttcuh
iTjianutlArffcular
Arttcf
Anter. Tihial Recurreivt-
386
ARTERIES.
it is in relation, above, with the femoral vein, and, lower down, with the Ad-
ductor longus, and Sartorius. To its outer side, the Vastus internus separates it
from the femur, in the lower part of its course.
The femoral vein, at Poupart's ligament, lies close to the inner side of the
artery, separated fi'om it by a thin fibrous partition, but, as it descends, gets
behind it, and then to its outer side.
The internal saphenous nerve, is situated on the outer side of the artery, in
the middle third of the thigh, beneath the aponeurotic covering, but not within
the sheath of the vessels. Small cutaneous nerves cross the front of the
sheath.
Peculiarities. Double femoral re-united. Four cases are at present recorded, in which
the femoral artery divided into two trunks below the origin of the Profunda, and became
re-united near the opening in the Adductor magnus, so as to form a single popliteal artery.
One of them occurred in a patient operated upon for popliteal aneurism.
Change of Position. A similar number of cases have been recorded, in which the
femoral artery was situated at the back of the thigh, the vessel being continuous above
with the internal iliac, escaping from the pelvis through the great sacro-sciatic foramen,
and accompanying the great sciatic nerve to the popliteal space, where its division oc-
curred in the usual manner.
Position of the Vein. The femoral vein is occasionally placed along the inner side of the
artery, throughout the entire extent of Scarpa's triangle ; or it may be slit, so that a large
vein is placed on each side of the artery for a greater or less extent.
Origin of the Profunda. This vessel occasionally arises from the inner side, and more
rarely, from tl.e back of the common trunk ; but the more important peculiarity, in a
surgical point of view, is that which relates to the height at which the vessel arises from
the femoral. In three-fourths of a large number of cases it arose between one and two
inches below Poupart's ligament ; in a few cases, the distance was less than an inch ; more
rarely, opposite the ligament ; and in one case, above Poupart's Hgament, from the external
iliac. Occasioually, the distance between the origin of the vessel and Poupart's liga-
ment, exceeds two inches, and in one case, it was found to be as much as four inches.
Surgical Anatomy. Compression of the femoral artery, which is constantly requisite in
amputations, or other operations on the lower limb, is most effectually made immediately
below Poupart's ligament. In this situation, the artery is very superficial, and is merely
separated from the margin of the acetabulum and front of the head of the femur, by the
Psoas muscle ; so that the surgeon, by means of his thumb, or any other resisting body,
may effectually control the circulation through it. This vessel may also be compressed
in the middle third of the thigh, by placing a compress over the artery, beneath the
tourniquet, and directing the pressure from within outwards, so as to compress the vessel
on the inner side of the shaft of the femur.
The application of a ligature to the femoral artery may be required in cases of wound
or aneurism of the arteries of the leg, of the popliteal or femoral ; and the vessel may be
exposed and tied in any part of its course. The great depth of this vessel in the middle
of the thigh, its close connection with important structures, and the density of its sheath,
render the operation in this situation one of much greater difficulty than the application
of a ligature in the upper part of its course, where it is more superficial.
Ligature of the femoral artery, within two inches of its origin, is usually considered
very unsafe, on account of the connection of large branches with it, the epigastric
and circumflex iliac arising just above its origin ; the profunda, from one to two inches
below; occasionally, also, one of the circumflex arteries arises from the vessel in the
interspace between these. The profunda sometimes arises higher than the point above-
mentioned, and rarely between two or three inches (in one case four,) below Poupart's
ligament. It would appear, then, that the most favourable situation for the application of
a ligature to this vessel, is between four and five inches from its point of origin. In order
to expose the artery in this situation, an incision, between two and three inches long,
should be made in the course of the vessel, the ' patient lying in the recumbent posi-
tion, with the limb slightly flexed and abducted. A large vein is frequently met with,
passing in the course of the artery to join the saphena; this must be avoided, and the
fascia lata having been cautiously divided, and the Sartorius exposed, this muscle must be
drawn outwards, in order to fully expose the sheath of the vessels. The finger being in-
troduced into the wound, and the pulsation of the artery felt, the sheath should be divided
over it to a sufficient extent to allow of the introduction of the ligature, but no further;
otherwise the nutrition of the coats of the vessel may be interfered with, or muscular
branches which arise from the vessel at irregular intervals may be divided. In this part
of the operation, a small nerve which crosses the sheath should be avoided. The aneurism
needle must be carefully introduced and kept close to the artery, to avoid the femoral vein,
which lies behind the vessel in this part of its course.
BRANCHES OF FEMORAL. 387
To expose the artery in the middle of the thigh, an incision should be made through
the integument, between three and four inches in length, over the inner margin of the
Sartorius, taking care to avoid the internal saphena vein, the situation of which may be
previously known by compressing it higher up in the thigh. The fascia lata having been
divided, and the Sartorius muscle exposed, it should be drawn outwards, when the strong
fascia which is stretched across from the Adductors to the Vastus internus, will be ex-
posed, and must be freely divided ; the sheath of the vessels is now seen, and must be
opened, and the artery secured by passing the aneurism needle between the vein and
artery, in the direction from within outwards. The femoral vein in this situation lies
on the outer side of the artery, the long saphenous nerve on its anterior and outer
side.
It has been seen that the femoral artery occasionally divides into two trunks, below
the origin of the profunda. If, in the operation for tying the femoral, two vessels are
met with, the surgeon should alternately compress each, in order to ascertain which vessel
is connected with the aneurismal tumour, or with the bleeding from the wound, and that
one only tied which controls it. If, however, it is necessary to compress both vessels
before the circulation in the tumour is controlled, both should be tied, as it would be
probable that they became re-united, as is mentioned above.
Branches. The branches of the femoral artery are the:
Superficial epigastric.
Superficial circumflex iliac.
Superficial external pudic.
Deep external pudic.
[ External circumflex.
Profunda j Internal circumflex.
I Three perforating.
Mu.scular.
Anastomotica magna.
The Superficial Epigastric arises from the femoral, about half an inch below
Poupart's ligament, and, passing through the saphenous opening in the fascia-lata,
ascends on to the abdomen, in the superficial fascia covering the External oblique
muscle, nearly as high as the umbilicus. It distributes branches to the inguinal
glands, the superficial fascia and integument, anastomosing with branches of the
deep epigastric, and internal mammary arteries.
The Superficial Circumfiex Iliac, the smallest of the cutaneous branches,
arises close to the preceding, and, piercing the fascia lata, runs outwards, parallel
with Poupart's ligament, as far as the crest of the Ilium, dividing into branches
which supply the integument of the groin, the superficial fascia, and inguinal
glands, anastomosing with the deep circumflex iliac, and with the gluteal and
external circumflex arteries.
The Superficial External Pudic (superior), arises from the inner side of the
femoral artery, close to the preceding vessels, and, after piercing the fascia lata
at the saphenous opening, passes inwards, across the spermatic cord, to be dis-
tributed to the integument on the lower part of the abdomen, and of the penis
and scrotum in the male, and to the labia in the female, anastomosing with
branches of the internal pudic.
The Deep External Pudic (inferior), more deeply seated than the preceding,
passes inwards on the Pectineus muscle, covered by the fascia lata, which it
pierces opposite the ramus of the pubes, its branches being distributed, in the
male, to the integument of the scrotum and perinaeum, and in the female, to the
labium, anastomosing with branches of the superficial perin^eal artery.
The Profunda Femoris (deep femoral artery), nearly equals the size of the
superficial femoral. It arises from the outer and back part of the femoral artery,
from one to two inches below Poupart's ligament. It at first lies on the outer
side of the superficial femoral, and then passes beneath it and the femoral vein to
the inner side of the femur, and terminates at the lower third of the thigh in a
small branch, which pierces the Adductor magnus, to be distributed to the Flexor
muscles, on the posterior part of the thigh, anastomosing with branches of the
popliteal and inferior perforating arteries.
c c 2
388 ARTERIES.
Relations. Behind, it lies first upon the Iliacus, and then on the Adductor
brevis and Adductor magnus muscles. In front, it is separated from the femoral
artery; above, by the femoral and profunda veins; and below, by the Adductor
longus. On its outer side, the insertion of the Vastus internus separates it from
the femur.
c Plan of the Relations of the Pkofunda Artery.
i
In front.
Femoral and profunda veins.
Adductor longus.
Outer side.
Vastus internus.
Behind.
Iliacus.
Adductor brevis.
Adductor magnus.
The External Circumflex Artery supplies the muscles on the front of the thigh.
It arises from the outer side of the profunda, passes horizontally outwards, be-
tween the divisions of the anterior crural nerve, and beneath the Sartorius and
Rectus muscles, and divides into three sets of branches, ascending, ti-ansverse, and
descending.
The ascending branches pass upwards, beneath the Tensor vaginae femoris
muscle, to the outer side of the hip, anastomosing with the terminal branches
of the gluteal, and circumflex iliac arteries.
The descending branches, three or four in number, pass downwards, beneath
the Rectus, upon the Vasti muscles, to which they are distributed, one or two
passing beneath the Vastus externus as far as the knee, anastomosing with the
superior articular branches of the popliteal artery.
The transverse branches, the smallest and least numerous, pass outwards over
the Crurteus, pierce the Vastus externus, and wind around the femur to its back
part, just below the great trochanter, anastomosing at the back of the thigh with
the internal circumflex, sciatic, and superior perforating arteries.
The Internal Circumflex Artery, smaller than the external, arises from the
inner and back part of the profunda, and winds around the inner side of the
femur, between the Pectineus and Psoas muscles. On reaching the tendon of the
Obturator externus, it divides into two branches; one, ascending, is distributed to
the Adductor muscles, the Gracilis, and Obturator externus, anastomosing with
the obturator artery, a descending branch which passes beneath the Adductor
brevis, to supply it and the great Adductor ; the continuation of the vessel passing
backwards, between the Quadratus femoris and upper border of the Adductor
magnus, anastomosing with the sciatic, external circumflex, and superior perforat-
ing arteries. Opposite the hip-joint, this branch gives off an articular vessel, which
enters the joint beneath the transverse ligament; and, after supplying the adipose
tissue, passes along the round ligament to the head of the bone.
The Ferforatiyig Arteries (fig. 2 1 o), usually three in number, are so called from
their perforating the tendons of the Adductor brevis and Magnus muscles to reach
the back of the thigh.
The First or Superior Perforating Artery passes backwards between the Pec-
tineus and Adductor brevis (sometimes perforates the latter); it then pierces
the Adductor magnus close to the linea aspera, and divides into branches which
supply both Adductors, the Biceps, and Gluteus maximus muscle; anastomosing
Avith the sciatic, internal circumflex, and middle perforating arteries.
POPLITEAL. 389
The Second or Middle Perforating Artery, larger than the first, passes through
the tendons of the Adductor brevis and Adductor magnus muscles, divides
into ascending and descending branches, which supply the flexor muscles of the
thigh; anastomosing with the superior and inferior perforantes. The nutrient
artery of the femur is usually given off from this branch.
The Third or Inferior Perforating Artery is given off below the Adductor
brevis; it pierces the Adductor magnus, and divides into branches which supply
the flexor muscles of the thigh; anastomosing with the perforating arteries, above,
and with the terminal branches of the profunda, below.
Muscular Branches are given off from this vessel throughout its entire course.
They vary from two to seven in number, and supply chiefly the Sartorius and
Vastus internus.
The Anastomotica Magna arises from the femoral artery just before it passes
through the tendinous opening in the Adductor magnus muscle, and divides into a
superficial and deep branch.
The superficial branch accompanies the long saphenous nerve, beneath the
Sartorius, and piercing the fascia lata, is distributed to the integument.
The deep branch descends in the substance of the Vastus internus, lying in front
of the tendon of the Adductor magnus, to the inner side of the knee, where it
anastomoses with the superior internal articular artery and recurrent branch of the
anterior tibial. A branch from this vessel crosses outwards above the articular
surface of the femur, forming an anastomotic arch with the superior external arti-
cular artery, and supplies branches to the knee-joint.
Popliteal Artery.
The popliteal artery commences at the termination of the femoral, at the
opening in the Adductor magnus, and passing obliquely downwards and outwards
behind the knee-joint, to the lower border of the Popliteus muscle, divides into the
anterior and posterior tibial arteries. Through this extent the artery lies in the
popliteal space.
The Popliteal Space.
Dissection. A vertical incision about eight inches in length should be made along the back
part of the knee-joint, connected above and below by a transverse incision passing from the
inner to the outer side of the limb. The flaps of integument included between these inci-
sions should be reflected in the direction shown in fig. 171.
On removing the integument, the superficial fascia is exposed, and ramifying in
it along the middle line are found some filaments of the small sciatic nerve, and
towards the inner part, some offsets from the internal cutaneous nerve.
The superficial fascia having been removed, the fascia lata is brought into view.
Li this region it is strong and dense, being strengthened by transverse fibres, and
firmly attached to the tendons on the inner and outer sides of the space. It is
perforated below by the external saphena vein. This fascia having been reflected
back in the same direction as the integument, the small sciatic nerve and ex-
ternal saphena vein are seen immediately beneath it, in the middle line. If
the loose adipose tissue is now removed, the boundaries and contents of the space
inay be examined.
Boundaries. The popliteal space or the ham, occupies the lower third of the
thigh and the upper fifth of the leg ; extending from the aperture in the Adductor
magnus, to the lower border of the Popliteus muscle. It is a lozenge-shaped
space, being widest at the back part of the knee-joint, and deepest above the arti-
cular end of the femur. It is bounded, externally, above the joint, by the Biceps,
and below the articulation, by the Plautaris and external head of the Gastroc-
nemius. Internally, above the joint, by the Semi-membranosus, Semi-tendinosus,
Gracilis, and Sartorius; below the joint, by the inner head of the Gastrocnemius.
Above, it is limited by the apposition of the inner and outer hamstring muscles;
below, by the junction of the two heads of the Gastrocnemius. The floor is
390 ARTERIES.
formed by the lower part of the posterior surface of the shaft of the femur, the
post^erior ligament of the knee-joint, the upper end of the tibia, and the fascia
covering the Popliteus muscle, and the space is covered in by the fascia lata.
Contents. It contains the popliteal vessels and their branches, together with the
termination of the external saphena vein, the internal and external popliteal nerves
and their branches, the small sciatic nerve, the articular branch from the obturator
nerve, a few small lymphatic glands, and a considerable quantity of loose adipose
tissue.
Position of contained parts. The internal popliteal nerve descends in the middle
line of the space, lying superficial, and a little external to the vein and artery.
The external popliteal nerve descends on tlie outer side of the space, lying close
to the tendon of the Biceps muscle. More deeply at the bottom of the space are
the popliteal vessels, the vein lying suj)erficial and a' little external to the artery,
to which it is closely united by dense areolar tissue; sometimes the vein is placed
on the inner instead of the outer side of the artery; or the vein may be double,
the artery then lies between them, the two veins being usually connected by short
transverse branches. More deeply, and close to the surface of the bone, is the
jjopliteal artery, and passing oiF fi'om it at right angles are its articular branches.
The articular branch from the obturator nerve descends upon the popliteal artery
to supply the knee; and deeply in the space is an articular filament occasionally
derived from the great sciatic nerve. The popliteal lymphatic glands, four or
five in number, are found surrounding the artery; one usually lies superficial to
the vessel, another is situated between it and the bone, and the rest are placed
on either side of it. In health, these glands are small; but when enlarged
and indurated from inflammation, the pulsation communicated to them from the
popliteal artery makes them resemble so closely an aneurismal tumour, that it
requires a very careful examination to discriminate between them.
The Popliteal Artery (fig. 2 1 2), in its course downwards from the aperture in
the Adductor magnus, to the lower border of the Popliteus muscle, rests first on the
inner, and then on the posterior surface of the femur; in the middle of its course,
on the posterior ligament of the knee-joint; and below, on the fascia covering
the Popliteus muscle. Superficially, it is covered, above, by the Semi-membra-
nosus; in the middle of its course, by a quantity of fat, which separates it from the
deep fascia and integument; and below, it is overlapped by the Gastrocnemius,
Plantaris, and Soleus muscles, the popliteal vein, and the internal popliteal nerve.
The popliteal vein, which is intimately attached to the artery, lies superficial and
external to it, until near its termination, when it crosses it and lies to its inner
side. The popliteal nerve is still more superficial and external, crossing, however,
the artery below the joint, and lying on its inner side. Laterally, it is bounded
by the muscles which form the boundaries of the popliteal space.
Peculiarities in point of division. Occasionally the popliteal artery divides prematurely
into its terminal branches ; this division occurs most frequently opposite the knee-joint.
Unusual branches. This artery sometimes divides into the anterior tibial and peroneal,
the posterior tibial being wanting, or very small. In a single case, this artery divided into
three branches, the anterior and posterior tibial, and peroneal.
Surgical Anatomy. Ligature of the popliteal artery is required in cases of wound of that
vessel, but for aneurism of the posterior tibial, it is preferable to tie the superficial femoral.
The popliteal may be tied in the upper or lower part of its course; but in the middle of the
space the operation is attended with considerable diflSculty, from the great depth of the
artery, and from the extreme degree of tension of its lateral boundaries.
In order to expose the vessel in the upper part of its course, the patient should be placed
in the prone position, with the limb extended. An incision about three inches in length
should then be made through the integument, along the posterior margin of the Semimem-
branosus, and the fascia lata having been divided, this muscle must be drawn inwards, when
the pulsation of the vessel will be detected with the finger ; the nerve lies on the outer or
fibular side of the artery, the vein, superficial and also to its outer side ; having cautiously
separated it from the artery, the aneurism needle should be passed around the latter vessel
from without inwards.
To expose the vessel in the lower part of its course, where the artery lies between the
two heads of the Gastrocnemius, the patient should be placed in the same position as in
POrLlTEAL.
391
the preceding operation. An incision should then be made through the integument in the
middle line, commencing opposite the bend of the knee-joint, care being taken to avoid the
external saphena vein and nerve. After dividing the deep fascia and separating some dense
cellular membrane, the artery, vein, and nerve
will be exposed, descending between the two heads
of the Gastrocnemius. Some muscular branches
of the popliteal should be. avoided if possible, or
if divided, tied immediately. The leg being now
flexed, in order the more efifectually to separate
the two heads of the Gastrocnemius, the nerve
should be drawn inwards and the vein outwards,
and the aneurism needle passed between the ar-
tery and vein from without inwards.
The branches of the popliteal artery are
212. — The Popliteal, Posterior Tibial,
and Peroneal Arteries.
J I,
Muscular
Superior,
Inferior or Sur;
Superior external articular.
Superior internal articular.
Azygos articular.
Inferior external articular.
Inferior internal articular.
The Superior Muscular Branches, two or
three in number, arise from the upper part
of the popliteal artery, and are distributed
to the Flexor muscles of the leg and the
Vastus externus; anastomosing w^ith the
inferior perforating, and terminal branches
of the profunda.
The Inferior Muscular {Sural) are two
large branches vfhich are distributed to the
two heads of the Gastrocnemius and Plan-
taris muscles. They arise from the popliteal
artery opposite the knee-joint.
Cutaneous branches descend on each side
and in the middle of the limb, between the
Gastrocnemius and integument; they arise
separately from the popliteal artery, or from
some of its branches, and supply the integu-
ment of the calf.
The Superior Articular Arteries, two in
number, arise one on either side of the
popliteal, and wind around the femur
immediately above its condyles to the front
of the knee-joint.
The internal branch passes beneath the
tendon of the Adductor magnus, and di-
vides into two, one of which supplies
the Vastus internus, inosculating with the
anastomotica magna and inferior internal
articular; the other ramifies close to the
surface of the femur, supplying it and the
knee-joint, and anastomosing with the su-
perior external articular artery.
The externalbranch passes above the outer
condyle, beneath the tendon of the Biceps,
and divides into a superficial and deej) branch :
the superficial branch supplies the Vastus
i^^i
—Anterior Peroneal
392 ARTERIES.
externus, and anastomoses with the descending branch of the external circumflex
artery; the deep branch supplies the lower part of the femur and knee-joint, and
forms an anastomotic arch across the bone with the anastomotic artery.
The Azygos Articular is a small branch, arising from the popliteal artery
opposite the bend of the joint. It pierces the posterior ligament, and supplies
the ligaments and synovial membrane in the interior of the articulation.
The Inferior Articular Arteries, two in number, arise from the popliteal, beneath
the Gastrocnemius, and wind round the head of the tibia, below the joint.
The internal one passes below the inner tuberosity, beneath the internal lateral
ligament, at the anterior border of which it ascends to the front and inner side of
the joint, to supply the head of the tibia and the articulation of the knee.
The external one passes outwards above the head of the fibula, to the front of
the knee-joint, lying in its course beneath the outer head of the Gastrocnemius,
the external lateral ligament, and the tendon of the Biceps muscle, and divides
into branches, which anastomose with the artery of the opposite side, the superior
articular, and the recurrent branch of the anterior tibial.
Anterior Tibial Artery.
The anterior tibial artery commences at the bifurcation of the popliteal, at the
lower border of the Popliteus muscle, passes forwards between the two heads of
the Tibialis posticus, and through the aperture left between the bones at the
upper part of the interosseous membrane, to the deep part of the front of the leg;
it then descends on the anterior surface of the interosseous ligament and of the
tibia to the front of the ankle-joint, where it lies more superficial, and becomes
the dorsalis pedis. A line drawn from the inner side of the head of the fibula to
midway between the two malleoli, will be parallel with the course of this artery.
Relations. In the upper two-thirds of its extent, it rests upon the interosseous
ligament, to which it is connected by delicate fibrous arches thrown across it.
In the lower third, upon the front of the tibia, and the anterior ligament of the
ankle-joint. In the upper third of its course, it lies between the Tibialis anticus
and Extensor longus digitorum: in the middle third, between the Tibialis anticus
and Extensor proprius pollicis, Li the lower third it is crossed by the tendon
of the Extensor jiroprius pollicis, and lies between it and the innermost tendon of
the Extensor longus digitorum. It is covered, in the upper two-thirds of its
course, by the muscles which lie on either side of it, and by the deep fascia: in
the lower third, by the integument, annular ligament, and fascia.
The anterior tibial artery is accompanied by two veins (vense comites), which
lie one on either side of the artery; the anterior tibial nerve lies at first to its
outer side, and about the middle of the leg is placed superficial to it; at the lower
part of the artery the nerve is on the outer side.
Plan of the Relations of the Anterior Tibial Artery.
In front.
Integument, superficial and deep fasciae.
Tibialis anticus.
Extensor longus digitorum.
Extensor proprius pollicis.
Anterior tibial nerve.
Inner side. / \ Outer side.
Tibialis anticus. / Anterior \ Anterior tibial nerve.
Extensor proprius pollicis. \ Tibial. j Extensor longus digitorum.
\ / Extensor proprius pollicis.
Behind.
Interosseous membrane.
Tibia.
Anterior ligament of ankle-joint.
Pemliarities in Size. This vessel may be diminished in size, or it may be deficient to a
ANTERIOR TIBIAL.
393
2 1 3. — Surgical Anatomy of the Anterior
Tibial and Dorsalis Pedis Arteries.
greater or less extent, or it may be entirely wanting, its place being supplied by perforating
branches from the posterior tibial, or by the anterior division of the peroneal artery.
Course. This artery occasionally deviates in its
course towards the fibular side of the leg, regain-
ing its usual position beneath the annular liga-
ment at the front of the ankle. In two instances,
this vessel has approached the surface in the
middle of the leg, from this point onwards being
covered merely by the integument and fascia.
Surgical Anatomy. The anterior tibial artery
may be tied in the upper or lower part of the leg.
In the upper part, the operation is attended with
great difficulty, on account of the depth of the
vessel from the surface. An incision, about four
inches in length, should be made through the
integument, midway between the spine of the
tibia and the outer margin of the fibula, the fascia
and intermuscular septum between the Tibialis
anticus and Extensor communis digitorum being
divided to the same extent. The foot must be
flexed to relax these muscles, and they must be
separated from each other by the finger. The
artery is then exposed, deeply seated, lying upon
the interosseous membrane, the nerve lying ex-
ternally, and one of the vense comites on either
side; these must be separated from the artery
before the aneurism needle is passed around it.
To tie this vessel in the lower third of the leg
above the ankle-joint, an incision about three
inches in length should be made through the in-
tegument between the tendons of the Tibialis
anticus and Extensor proprius pollicis muscles,
the deep fascia being divided to the same ex-
tent ; the tendon on either side should be held
aside, when the vessel will be seen lying upon the
tibia, with the nerve superficial to it, and one of
the venae comites on either side.
In order to secure this vessel over the instep,
an incision should be made on the fibular side
of the tendon of the Extensor proprius pollicis,
between it and the innermost tendon of the long
Extensor : the deep fascia having been divided,
the artery wiU be exposed, the nerve lying either
superficial to it or to its outer side.
The branches of the anterior tibial artery-
are
Recurrent tibial.
Muscular.
Internal malleolar.
External malleolar.
The Recurrent Branch arises from the
anterior tibial as soon as that vessel has
passed through the interosseous space; it
ascends in the Tibialis anticus muscle, and
ramifies on the front and sides of the
knee-joint, anastomosing with the articular
branches of the popliteal.
The Muscular Branches are numerous;
they are distributed to the muscles which lie
on either side of this vessel, some piercing
the deep fascia to supply the integument,
others passing through the interosseous mem-
brane, and anastomosing with branches of
the posterior tibial and peroneal arteries.
394 ARTERIES.
The Malleolar Arteries supply the ankle-joint.
The internal, arises about two inches above the articulation, passes beneath
the tendon of the Tibialis anticus to the inner ankle, upon which it ramifies,
anastomosing with branches of the posterior tibial and internal plantar arteries.
The external passes beneath the tendons of the Extensor longus digitorum and
Extensor proprius pollicis, and supplies the outer ankle, anastomosing with the
anterior peroneal artery and with ascending branches from the tarsea branch of
the dorsalis pedis.
DoRSALis Pedis Artery.
The dorsalis pedis, the continuation of the anterior tibial, passes forwards
from the bend of the ankle along the tibial side of the foot to the back part of
the first interosseous space, where it divides into two branches, the dorsalis hal-
lucis and communicating.
Relations. This vessel in its course forwards rests upon the astragalus, sca-
phoid, and internal cuneiform bones, and the ligaments connecting them, being
covered by the integument and fascia, and crossed near its termination by the
innermost tendon of the Extensor brevis digitorum. On its tibial side is the
tendon of the Extensor proprius pollicis; on '\\j& fibular side, the innermost tendon
of the Extensor longus digitorum. It is accompanied by two veins, and by the
anterior tibial nerve, which lies on its outer side.
t';
Plan of the Relations of the Dorsalis Pedis Artery.
In front.
Integument and fascia.
Innermost tendon of Extensor breyis digitorum.
Tibial side. i j^^iocwio i -p, , , ■,. .,
•c . • IT • p^z-iic iiixtensor longus digitorum.
Extensor proprius poUicis. Pedis. i Ar^fpr^nr- «h^!l n™
Fibular side.
lor longus digi
Anterior tibial nerve.
Behind.
Astragalus.
Scaphoid.
Internal cuneiform,
and their ligaments.
Peculiarities in Size. The dorsal artery of the foot may be larger than usual, to compen-
sate for a deficient plantar artery ; or it may be deficient in its terminal branches to the
toes, which are then derived from the internal plantar ; or its place may be supplied alto-
gether by a large anterior peroneal artery.
Position. This artery frequently curves outwards, lying external to the line between the
middle of the ankle and the back of the first interosseous space.
Surgical Anatomy. This artery may be tied, by making an incision through the integu-
ment, between two and three inches in length, on the fibular side of the tendon of the
Extensor proprius pollicis, in the interval between it and the inner border of the short
Extensor muscle. The incision should not extend further forwards than the back part of
the first interosseous space, as the artery divides in this situation. The deep fascia being
divided to the same extent, the artery will be exposed, the nerve lying upon its outer
side.
Branches. The branches of the dorsalis pedis are, the
Tarsea. Interosseae.
Metatarsea. Dorsalis pollicis.
Communicating.
The Tarsea Artery arises from the dorsalis pedis, as that vessel crosses the
scaphoid bone; it passes in an arched direction outwards, lying upon the tarsal
bones, and covered by the Extensor brevis digitorum: it supplies that muscle and
the articulations of the tarsus, and anastomoses with bi'anches from the meta-
tarsea, external malleolar, peroneal, and external plantar arteries.
POSTERIOR TIBIAL.
395
The Metatarsea arises a little anterior to the preceding; it passes outwards to
the outer part of the foot, over the bases of the metatarsal bones, beneath the
tendons of the short Extensor, its direction being influenced by its point of
origin; and it anastomoses with the tarsea and external plantar arteries. This
vessel gives off three branches, the interosseas, which pass forwards upon the
three outer Dorsal interossei muscles, and, in the clefts between the toes, divide
into tAvo dorsal collateral branches for the adjoining toes. At the back part of
each interosseous space these vessels receive the posterior perforating branches
from the plantar arch; and at the fore part of each interroseous space, they are
joined by the anterior perforating branches, from the digital arteries. The outer-
most interosseous artery gives off a branch which supplies the outer side of the
little toe.
The Dorsalis Hallucis runs forwards along the outer surface of the first meta-
tarsal bone, and, at the cleft between the first and second toes, divides into two
branches, one of which passes inwards, beneath the tendon of the Flexor longus
pollicis, and is distributed to the inner border of the great toe; the other branch
bifurcating to supply the adjoining sides of the great and second toes.
The Communicating Artery dips down into the sole of the foot, between the
two heads of the first Dorsal interosseous muscle, and inosculates with the termi-
nation of the external plantar artery, to complete the plantar arch. It here gives
off two digital branches; one runs along the inner side of the great toe, on its
plantar surface; the other passes forwards along the first metatarsal space, and
bifurcates for the supply of the adjacent sides of the great and second toes.
PosTEEioK Tibial Artery.
The posterior tibial is an artery of lai-ge size, which extends obliquely down-
wards from the lower border of the Popliteus muscle, along the tibial side of the
leg, to the fossa between the inner ankle and the heel, where it divides beneath
the origin of the Abductor pollicis, into the internal and external plantar arteries.
At its origin it lies opposite the interval, between the tibia and fibula; as it
descends, it approaches the inner side of the leg, lying behind the tibia, and, in
the lower part of its course, is situated midway between the inner malleolus and
the tuberosity of the os calcis.
Relations. It lies successively upon the Tibialis posticus, the Flexor longus
digitorum, and below, upon the tibia and back part of the ankle-joint. It is
covered by the intermuscular fascia, which separates it above from the Gastroc-
nemius and Soleus muscles. In the lower third, where it is more superficial, it
is covered only by the integument and fascia, and runs parallel with the inner
border of the tendo Achillis. It is accompanied by two veins, and by the poste-
rior tibial nerve, which lies at first to the inner side of the artery, but soon
crosses it, and is, in the greater part of its course, on its outer side.
Plan of the Relations of the Posterior Tibial Artery,
In front.
Tibialis posticus.
Flexor longus digitorum.
Tibia. _
Ankle-joint.
Inner side. f \ Outer side.
Posterior tibial nerve, / Posterior ] Posterior tibial nerve,
upper third. \ Tibial. j lower two-tliirds.
Behind.
Gastrocnemius.
Soleus,
Deep fascia and integument.
396 ARTEEIES.
Behind the Inner Ankle, the tendons and blood-vessels are arranged in the
following order, from within outwards: First, the tendons of the Tibialis posticus
and Flexor longus digitorum, lying in the same groove, behind the inner mal-
leolus, the former being the most internal. External to these is the posterior
tibial artery, having a vein on either side ; and, still more externally, the posterior
tibial nerve. About half an inch nearer the heel is the tendon of the Flexor
longus poUicis.
Peculiarities in Size. The posterior tibial is not unfrequently smaller than usual, or
absent, its place being compensated for by a large peroneal artery, which passes inwards
at the lower end of the tibia, and either joins the small tibial artery, or continues alone to
the sole of the foot.
Surgical Anatomy. The application of a ligature to the posterior tibial may be required
in cases of wound of the sole of the foot, attended with great hsemorrhage, when the
vessel should be tied at the inner ankle. In cases of wound of the posterior tibial itself,
it will be necessary to enlarge the wound so as to expose the vessel at the wounded
point (excepting where the vessel is injured by a punctured wound from the front of the
leg). In cases of aneurism from wound of the artery low down, the vessel should be tied
in the middle of the leg. But in aneiu-ism of the posterior tibial high up, it would be
better to tie the femoral artery.
To tie the posterior tibial artery at the ankle, a semi-lunar incision should be made
through the integument, about two inches and a half in length, midway between the heel
and inner ankle, but a little nearer the latter. The subcutaneous cellular membrane
having been divided, a strong and dense fascia, the internal annular ligament, is exposed.
This ligament is continuous above with the deep fascia of the leg, covers the vessels and
nerves, and is intimately adherent to the sheaths of the tendons. This having been
cautiously divided upon a director, the sheath of the vessels is exposed, and being opened,
the artery is seen with one of the vena comites on each side. The aneurism needle
should be passed around the vessel from the heel towards the ankle, in order to avoid
the posterior tibial nerve, care being at the same time- taken not to include the vense
comites.
The vessel may also be tied in the lower third of the leg, by making an incision about
three inches in length, parallel with the inner margin of the tendo Achillis. The internal
saphena vein being carefully avoided, the two layers of fascia must be divided upon a
director, when the artery is exposed along the inner margin of the Flexor longus digito-
rum, with one of its venae comites on either side, and the nerve lying external to it.
To tie the posterior tibial in the middle of the leg, is a very difficult operation, on
account of the great depth of the vessel from the surface, and from its being covered in
by the Gastrocnemius and Soleus muscles. The patient being placed in the recum-
bent position, the injured limb should rest on its outer side, the knee being partially
bent, and the foot extended, so as to relax the muscles of the calf. An incision about
four inches in length should then be made through the integument, along the inner margin
of the tibia, taking care to avoid the internal saphena vein. The deep fascia having been
divided, the margin of the Gastrocnemius is exposed, and must be drawn aside, and the
tibial attachment of the Soleus divided, a director being previously passed beneath it.
The artery may now be felt pulsating beneath the deep fascia, about an inch from the
margin of the tibia. The fascia having been divided, and the limb placed in such a posi-
tion as to relax the muscles of the calf as much as possible, the veins should be separated
from the artery, and the aneurism needle passed around the vessel from without inwards,
so as to avoid wounding the posterior tibial nerve.
The branches of the posterior tibial artery are, the
Peroneal. Nutritious.
Muscular. Communicating.
Internal calcanean.-
The Peroneal Artery lies, deeply seated, along the back part of the fibular
side of the leg. It arises from the posterior tibial, about an inch below the
lower border of the Popliteus muscle, passes obliquely outwards to the fibula, and
then descends along the inner border of this bone to the lower third of the leg,
where it gives off the anterior peroneal. It then descends across the articulation,
between the tibia and fibula, to the outer side of the os calcis, supplying the
neighbouring muscles and back of the ankle, and anastomosing with the external
malleolar, tarsal, and external plantar arteries.
Relations. This vessel rests at first upon the Tibialis posticus, and, in the
PERONEAL. 397
greater part of its course, in the fibres of the Flexor longus pollicis, in a groove
between the interosseous ligament and the bone. It is covered, in the upper part
of its course, by the Soleus and deep fascia; below, by the Flexor longus pollicis.
Plan of the Relations of the Peroneal artery.
In front.
Tibialis posticus.
Flexor longus pollicis.
Outer side.
Fibula.
Behind.
Soleus.
Deep fascia.
Flexor longus pollicis.
Peculiarities in Origin. The peroneal artery may arise three inches below the popli-
teus, or from the posterior tibial high up, or even from the popliteal.
Its Size is more frequently increased than diminished, either reinforcing the posterior
tibial by its junction with it, or by altogether taking the place of the posterior tibial, in
the lower part of the leg and foot, the latter vessel only existing as a short muscular
branch. In those rare cases, where the peroneal artery is smaller than usual, a branch
from the posterior tibial supplies its place, and a branch from the anterior tibial compen-
sates for the diminished anterior peroneal artery. In one case, the peroneal artery has
been found entirely wanting.
The anterior peroneal is sometimes enlarged, and takes the place of the dorsal artery of
the foot.
The peroneal artery, in its course, gives off branches to the Soleus, Tibialis
posticus, Flexor longus pollicis, and Peronei muscles, and a nutrient branch to the
fibula.
The Anterior Peroneal pierces the interosseous membrane, about two inches
above the outer malleolus, to reach the fore part of the leg, and, passing down
beneath the peroneus tertius to the outer ankle, ramifies on the front and outer side
of the tarsus, anastomosing with the external malleolar and tarsal arteries.
The Nutritious Artery of the tibia arises from the posterior tibial near its
origin, and after supplying a few muscular branches, enters the nutritious canal
of that bone, which it traverses obliquely from above downwards. This is the
largest nutrient artery of bone in the body.
The Muscular Branches are distributed to the Soleus and deep muscles along
the back of the leg.
The Communicating Branch to the peroneal passes transversely across the
back of the tibia, about two inches above its lower end, passing beneath the
Flexor longus pollicis.
The Internal Calcanean consists of several large branches, which arise from
the posterior tibial just before its division; they are distributed to the fat and
integument behind the tendo Achillis and about the heel, and to the muscles on
the inner side of the sole, anastomosing with the posterior peroneal and intei'nal
malleolar arteries.
The Internal Plantar Artery, much smaller than the external, passes forwards
along the inner side of the foot. It is at first situated above the Abductor pollicis,
and then between it and the Flexor brevis digitorum, both of which it supplies.
At the base of the first metatarsal bone, where it has become much diminished in
size, it passes along the inner border of the great toe, inosculating with its digital
branches.
The External Plantar Artery, much larger than the internal, passes obliquely
outwards and forwards to the base of the fifth metatarsal bone. It then turns
obliquely inwards to the interval between the bases of the first and second meta-
398
ARTERIES.
tarsal bones, where it inosculates with the communicating branch from the dorsalis
pedis artery, thus completing the plantar arch. As this artery passes outwards it
is at first placed between the os calcis and Abductor pollicis, and then between
the Flexor brevis digitorum and Flexor accessorius; and as it passes forwards
to the base of the little toe, it lies more superficial between the Flexor brevis
digitorum and Abductor minimi digiti, covered by the deep fascia and integument.
The remaining portion of the vessel is deeply situated: it extends from the base
of the metatarsal bone of the little toe to the back part of the first interosseous
space, and forms the plantar arch; it is convex forwards, lies upon the Interossei
214. — The Plantar Arteries.
Superficial View.
215. — The Plantar Arteries.
Deep View.
muscles, opposite the tarsal ends of the metatarsal bones, and is covered by the
Adductor pollicis, the flexor tendons of the toes, and the Lumbricales.
Branches. The plantar arch, besides distributing numerous branches to the
muscles, integument, and fasciae in the sole, gives ofi" the following branches:
Posterior perforating.
Digital — Anterior perforating.
The Posterior Perforating are three small branches, which ascend through the
back part of the three outer interosseous spaces, between the heads of the dorsal
Interossei muscles, and anastomose with the interosseous branches from the meta-
tarsal artery.
The Digital Branches are four in number, and supply the three outer toes and
half the next. The^r^^ passes outwards from the outer side of the plantar arch,
and is distributed to the outer side of the little toe, passing in its course beneath
the Abductor and short Flexor muscles. The second, third, and fourth run for-
wards along the metatarsal spaces, and on arriving at the clefts between the toes,
divide into collateral branches, which supply the adjacent sides of the three outer
toes and the outer side of the second. At the bifurcation of the toes, each digital
artery sends upwards, through the fore part of the corresponding metatarsal space.
PLANTAR.
399
a small branch, which inosculates with the interosseous branches of the metatarsal
artery. These are the anterior perforating arteries.
From the arrangement already described of the distribution of the vessels to
the toes, it will be seen that both sides of the three outer toes, and the outer side
of the second toe, are supplied by branches from the plantar arch; both sides of
the great toe, and the inner side of the second, being supplied by the dorsal artery
of the foot.
Pulmonary Artery.
The pulmonary artery conveys the dark impure venous blood from the right
side of the heart to the lungs. It is a short wide vessel, about two inches in
length, arising from the left side of the base of the right ventricle, in front of the
ascending aorta. It ascends obliquely upwards, backwards, and to the left side,
as far as the under surface of the arch of the aorta, where it divides into two
branches of nearly equal size, the right and left pulmonary arteries.
Relations. The greater part of this vessel is contained, together with the
aorta, in the pericardium, being enclosed with it in a tube of serous membrane,
continued upwards from the base of the heart, and has attached to it, above, the
fibrous layer of this membrane. Behind, it rests at first upon the ascending aorta,
and higher up in front of the left auricle. On either side of its origin is the
appendix of the corresponding auricle and a coronary artery; and higher up it
passes to the left side of the ascending aorta. A little to the left of its point of
bifurcation it is connected to the under surface of the arch by a short fibrous cord,
the remains of a vessel peculiar to foetal life, the ductus arteriosus.
The Right Pulmonary Artery, longer and larger than the left, runs horizon-
tally outwards, behind the ascending aorta and superior vena cava, to the root of
the right lung, where it divides into two branches, of which the lower, the larger,
supplies the lower lobe, the upper giving a branch to the middle lobe.
The Left Pulmonary Artery, shorter but somewhat smaller than the right,
passes horizontally in front of the descending aorta and left bronchus to the root
of the left lung, where it divides into two branches for the two lobes.
Of the Veins.
THE Veins are the vessels which serve to return the blood from the capillaries
of the different parts of the body to the heart. They consist of two distinct
sets of vessels, the pulmonary and systemic.
The Pulmonary Veins, unlike other vessels of this kind, contain arterial blood,
which they return from the lungs to the left auricle of the heart.
The Systemic Veins return the venous blood from the body generally to the
right auricle of the heart.
The Portal Vein, an appendage to the systemic venous system, is confined to
the abdominal cavity, returning the venous blood from the viscera of digestion,
and carrying it to the liver by a single trunk of large size, the vena portge. From
this organ the same blood is conveyed to the inferior vena cava by means of the
hepatic veins.
The veins, like the arteries, are found in nearly every tissue of the body; they
commence by minute plexuses, which communicate with the capillaries, the branches
from which, uniting together, constitute trunks, which increase in size as they
pass towards the heart, from the termination of larger branches in them. The
veins are larger and altogether more numerous than the arteries; hence the entire
capacity of the venous system is much greater than the arterial; the pulmonary
veins excepted, which do not exceed in capacity the pulmonary arteries. From
the combined area of the smaller venous branches being greater than the main
trunks, it results that the venous system represents a cone, the summit of which
corresponds to the heart, its base to the circumference of the body. In form, the
veins are not perfectly cylindrical, like the arteries, their walls being collapsed
when empty, and the uniformity of their surface being interrupted at intervals by
slight contractions, which indicate the existence of valves in their interior. They
usually retain, however, the same calibre as long as they receive no neighbouring
branches.
The veins communicate very freely with one another, especially in certain
regions of the body ; and this communication exists between the larger trunks as
well as between the smaller branches. Thus, in the cavity of the cranium, and
between the veins of the neck, where obstruction of the cerebral venous system
would be attended with imminent danger, we find that the sinuses and larger
veins have large and very frequent anastomoses. The same free communication
exists between the veins throughout the whole extent of the spinal canal, and
between the veins composing the various venous plexuses in the abdomen and
pelvis, as the spermatic, uterine, vesical, prostatic, etc.
The veins are subdivided into three sets; superficial, deep, and sinuses.
The Superficial or Cutaneous Veins are found between the layers of superficial
fascia, immediately beneath the integument: they return the blood from these struc-
tures, and communicate with the deep veins by perforating the deep fascia.
The Deep Veins accompany the arteries, and are usually enclosed in the same
sheath with those vessels. In the smaller arteries, as the radial, ulnar, brachial,
tibial, peroneal, they exist generally in pairs, one lying on each side of the vessel,
and are called venoe comites. The larger arteries, as the axillary, subclavian,
popliteal, and femoral, have usually only one accompanying vein. In certain
organs of the body, however, the deep veins do not accompany the arteries ; for
instance, the veins in the skull and spinal canal, the hepatic veins in the liver, and
the larger veins returning blood from the osseous tissue.
Sinuses are venous channels, which, in their structure and mode of distribution,
differ altogether from the veins. They are found only in the interior of the skull,
GENERAL ANATOMY. 401
and are formed by a subdivision of the layers of the dura mater; their outer coat
consisting of fibrous tissue, their inner of a serous membrane continuous with the
serous membrane of the veins.
Veins are thinner in structure than the arteries, and possessed of considerable
strength. The superficial veins usually have thicker coats than the deep veins,
and the veins of the lower limb are thicker than those of the upper.
Veins are composed of three coats, internal, middle, and external.
The Internal is an epithelial and elastic coat, consisting of an epithelial lining
supported on several laminae of longitudinal elastic fibres. It is less brittle in
structure than the same coat in the arteries, and its laminas, seldom fenestrated.
The Middle or Contractile Coat, thinner than that of the arteries, consists of
numerous alternating layers of muscular and elastic fibres. The muscular fibres
are disposed in a circular form around the vessel, intermixed with areolar tissue
and elastic fibi'es. The elastic coat consists of well developed elastic fibres, reti-
culating in a longitudinal direction. This coat is best marked in the splenic and
portal veins, and appears to be wanting in the hepatic part of the vena cava, in
the hepatic and subclavian veins.
Muscular tissue is also wanting in the veins: i. Of the maternal part of the
placenta. 2. In most of the cerebral veins and sinuses of the dura mater. 3. In
the veins of the retina. 4. In the veins of the cancellous tissue of bones. 5. In
the venous spaces of the corpora cavernosa. The veins of the above mentioned
parts consist of an internal epithelial lining, supported on one or more layers
of areolar tissue. On the other hand, muscular tissue is abundantly developed in
the veins of the gravid uterus, being found in all three coats; and in the venaB cavge
and pulmonary veins, it is prolonged on to them from the auricles of the heart.
The External or Areolar Fibrous Coat consists of areolar tissue and longi-
tudinal elastic fibres, it also contains in some of the larger veins a longitudinal net-
work of non-striated muscular fibres, as in the whole length of the inferior vena
cava, the renal, azygos, and external iliac veins, and in all the large trunks of the
portal venous system, and in the trunks of the hepatic veins.
Most veins are provided with valves which serve to prevent the reflux of the
blood. They are formed by a reduplication of the lining membrane, strengthened
by a little fibrous tissue; their form is semilunar, they are attached by their convex
edge to the wall of the vein, the concave margin is free, directed in the course
of the venous current, and lies in close apposition with the wall of the vein as
long as the current of blood takes its natural course ; if, however, any regurgitation
takes place, the valves become distended, their opposed edges are brought into con-
tact, and the current is intercej^ted. Most commonly two such valves are found,
placed opposite one another, more especially in the smaller veins, or in the larger
trunks at the point where they are joined by small branches; occasionally there
are three, and sometimes only one. The wall of the vein immediately above the
point of attachment of each segment of the valve, is expanded into a pouch or
sinus, which gives to the vessel, when injected or distended with blood, a knotted
appearance. The valves are very numerous in the veins of the extremities, espe-
cially the lower ones, these vessels having to conduct the blood against the force
of gravity. They are absent in the very small veins, also in the vense cava3, the
hepatic vein, portal vein and its branches, the renal, uterine, and ovarian
veins. A few valves are found in the spermatic veins, and one also at their
point of junction with the renal vein and inferior cava in both sexes. The
cerebral and spinal veins, the veins of the cancellated tissue of bone, the
pulmonary veins, and the umbilical vein and its branches, are also destitute of
valves. They are occasionally found, few in number, in the venae azygos and
intercostal veins. ^
The veins are supplied with nutrient vessels, vasa vasorum, like the arteries;
but nerves are not generally found distributed upon them, the only vessels upon
which they have at present been traced are the inferior vena cava and cerebral
veins.
402
VEINS
The veins may be arranged into three groups. I. Those of the head and neck,
upper extremity, and thorax, which terminate in the superior vena cava. 2. Those
of the lower limb, pelvis, and abdomen, which terminate in the inferior vena cava.
3. The cardiac veins, which open directly into the right auricle of the heart.
Veins of the Head and Neck.
The veins of the head and neck may be subdivided into three groups. I. The
veins of the exterior of the head. 2. The veins of the neck. 3. The veins of
the diploe and interior of the cranium.
The veins of the exterior of the head' are the
Facial.
Temporal.
Internal Maxillary.
Temporo-maxillary.
Posterior auricular!
Occipital.
216. — Veins of the Head and Neck.
Frontal
//// /■•/////
The Facial Vein passes obliquely across the side of the face, extending from
the inner angle of the orbit, downwards and outwards, to the anterior margin of
the Masseter muscle. It lies to the outer side of the facial artery, and is not so
OF THE HEAD AND FACE. 403
tortuous as that vessel. It commences in the frontal region, where it is called the
frontal vein; at the inner angle of the eye it has received the name of the angular
vein; and from this point to its termination, ih^ facial vein.
'Y\\.Q frontal vein commences on the anterior part of the skull, by a venous
plexus, which communicates with the anterior branches of the temporal vein; the
veins converge to form a single trunk, which descends along the middle line of the
forehead parallel with the vein of the opposite side, and unites with it at the root
of the nose by a transverse trunk, called the nasal arch. Occasionally the frontal
veins join to form a single trunk which bifurcates at the root of the nose into the
two angular veins. At the nasal arch the branches diverge, and run along the side
of the root of the nose. The frontal vein as it descends upon the forehead, re-
ceives the supi'a-orbital vein; the dorsal veins of the nose terminate in the nasal
arch; and the angular vein receives, on its inner side, the veins of the ala nasi; on
its outer side, the superior palpebral vein ; it moreover communicates with the oph-
thalmic vein, which establishes an important anastomosis between this vessel and
the cavernous sinus.
The facial vein commences at the inner angle of the orbit, being a continua-
tion of the angular vein. It passes obliquely downwards and outwards, beneath
the great Zygomatic muscle, descends along the anterior border of the Masseter,
crosses over the body of the lower jaw, with the facial artery, and, passing
obliquely outwards and backwards, beneath the Platysma and cervical fascia,
unites with a branch of communication from the temporo-maxillary vein, to form
a trunk of large size which enters the internal jugular.
Branches. The facial vein receives, near the angle of the mouth, communi-
cating branches from the pterygoid-plexus. It is also joined by the inferior
palpebral, the superior and inferior labial veins, the buccal veins from the cheek,
and the masseteric veins. Below the jaw, it receives the submental, the
inferior palatine, which returns the blood from the plexus around the tonsil
and soft palate; the submaxillary vein, which commences in the submaxillary
gland; and lastly, the ranine vein.
The Temporal Vein commences by a minute plexus on the side and vertex of
the skull, which communicates with the frontal vein in front, the corresponding
vein of the opposite side, and the posterior auricular and occipital veins behind.
From this network, anterior and posterior branches are formed which unite above
the zygoma, forming the trunk of the vein. This trunk is joined in this situation
by a large vein, the middle temporal, which receives the blood from the substance
of the Temporal muscle and pierces the fascia at the upper border of the
zygoma. The temporal vein then descends between the external auditory meatus
and the condyle of the jaw, enters the substance of the parotid gland, and unites
with the internal maxillary vein, to form the temporo-maxillary.
Branches. The temporal vein receives in its course some parotid veins, an articular
branch from the articulation of the jaw, anterior auricular veins from the external
ear, and a vein of large size, the transverse facial, from the side of the face.
The Internal Maxillary Vein is a vessel of considerable size, receiving
branches which correspond with those derived from the internal maxillary artery.
Thus it receives the middle meningeal veins, the deep temporal, the ptery-
goid, masseteric, and buccal, some palatine veins, and the inferior dental. These
branches form a large plexus, the pterygoid, which is placed between the
Temporal and External pterygoid, and partly between the Pterygoid muscles.
This plexus communicates very freely with the facial vein, and with the cavern-
ous sinus, by branches through the base of the skull. The trunk of the vein
then passes backwards, behind the neck of the lower jaw, and unites with the
temporal vein, forming the temporo-maxillary.
The Temporo- Maxillary Vein, formed by the union of the temporal and in-
ternal maxillary veins, descends in the substance of the parotid gland, between
the ramus of the jaw and the Sterno-mastoid muscle, and divides into tv/o
branches, one of which passes inwards to join the facial vein, the other is
D D 2
404 VEINS
continuous with the external jugular. It receives near its termination the posterior
auricular vein.
The Posterior Auricular Vein commences upon the side of the head, by a
plexus which communicates with the branches of the temporal and occipital
veins, descending behind the external ear. It joins the temporo-maxillary,
just before that vessel terminates in the external jugular. This vessel receives
the stylo-mastoid vein, and some branches from the back part of the external
ear.
The Occipital Vein commences at the back part of the vertex of the skull, by
a plexus in a similar manner with the other veins. It follows the course of the
occipital artery, passing deeply beneath the muscles of the back part of the
neck, and terminates in the internal jugular, occasionally in the external jugular.
As this vein passes opposite the mastoid process, ,it receives the mastoid vein,
which establishes a communication with the lateral sinus.
Veins of the Neck.
The veins of the neck, which return the blood from the head and face,
are the
External jugular. Anterior jugular.
Posterior external jugular. In textual jugular.
Vertebral.
The External Jugular Vein receives the greater part of the blood from the
exterior of the cranium and deep parts of the face, being a continuation of the
temporo-maxillary and posterior auricular veins. It commences in the substance
of the parotid gland, on a level with the angle of the loAver jaw, and runs perpen-
dicularly down the neck, in the direction of a line drawn from the angle of the
jaw to the middle of the clavicle. In its course, it crosses the Sterno-mastoid
muscle, and runs parallel with its posterior border as far as its attachment
to the clavicle, where it perforates the deep fascia, and terminates in the subcla-
vian vein, on the outer side of the internal jugular. As it descends ihe neck, it
is separated from the Sterno-mastoid by the anterior layer of the deep cervical
fascia, and is covered by the Platysma, the superficial fascia, and the integument.
This vein is crossed about its centre by the superficial cervical nerve, and its
upper half is accompanied by the auricularis magnus nerve. The external jugular
vein varies in size, bearing an inverse proportion to that of the other veins of the
neck: it is occasionally double. It is provided with two valves, one being placed
at its entrance into the subclavian vein, and a second in most cases about the
middle of its course. These valves do not prevent the regurgitation of the
blood, or the passage of injection from below upwards.
Branches. This vein receives the occipital, the posterior external jugular, and,
near its termination, the supra-scapular and transverse cervical veins. It com-
municates with the anterior jugular, and, in the substance of the parotid, receives
a large branch of communication from the internal jugular.
The Posterior External Jugular Veiyi returns the blood from the integument
and superficial muscles in the upper and back part of the neck, lying between
the Splenius and Trapezius muscles. It descends the back part of the neck, and
opens into the external jugular just below the middle of its course.
The Anterior Jugular Veiti collects the blood from the integument and muscles
in the middle of the anterior region of the neck. It passes down between the
median line and the anterior border of the Sterno-mastoid, and, at the lower
part of the neck, passes beneath that muscle to open into the subclavian vein,
near the termination of the external jugular. This vein varies considerably
in size, bearing almost always an inverse proportion to the external jugular.
Most frequently there are two anterior jugulars, a right, and left; but occasion-
OF THE NECK. 405
ally only one. This vein X'eceives some laryngeal brandies, and occasionally an
inferior thyroid vein. Just above the sternum, the two anterior jugular veins
communicate by a transverse trunk, which receives branches from the inferior
thyroid veins. It also communicates with the external and with the internal
jugular.
The Internal Jugular Vein collects the blood from the interior of the cra-
nium, from the superficial parts of the face, and from the neck. It commences
at the jugular foramen, in the base of the skull, being formed by the coalescence
of the lateral and inferior petrosal sinuses. At its origin it is somewhat
dilated, and this dilatation is called the sinus, or gulf of the internal jugular
vein. It runs down the side of the neck in a vertical direction, lying at
first on the outer side of the internal carotid, and then on the outer side of the
common carotid, and at the root of the neck unites with the subclavian vein, to
form the vena innominata. The internal jugular vein, at its commencement,
lies upon the Rectus lateralis, behind, and at the outer side of the internal
carotid, and the eighth and ninth pairs of nerves; lower down, the vein and
artery lie upon the same plane, the glosso-pharyngeal and hypoglossal nerves pass-
ing forwards between them; the pneumogastric descends between and behind them,
in the same sheath; and the spinal accessory passes obliquely outwards, behind
the vein. At the root of the neck the vein of the right side is placed at a little
distance from the artery; on the left side, it usually crosses it at its lower part.
This vein is of considerable size, but varying in diiFerent individuals, the left one
being usually the smallest. It is provided with two valves, which are placed
at its point of termination, or from one to two inches above it.
Branches. This vein receives in its course, the facial, lingual, pharyngeal,
superior and middle thyroid veins, and the occipital. At its point of junction
with the branch common to the temporal and facial veins, it becomes greatly
increased in size.
The Lingual Veins commence on the dorsum, sides, and under surface of the
tongue, and, passing backwards, following the course of the lingual artery and
its branches, terminate in the internal jugular.
The Pharyngeal Vein commences in a minute, plexus, the pharyngeal, at the
back part and sides of the pharynx, and after receiving meningeal branches, and
some from the vidian and spheno-palatine veins, terminates in the internal jugular.
It occasionally opens into the facial, lingual, or superior thyroid vein.
The Superior Thyroid Vein commences in the substance and on the surface of
the thyroid gland, by branches corresponding with those of the superior thyroid
artery, and terminates in the upper part of the internal jugular vein.
The Middle Thyroid Vein collects the blood from the lower part of the lateral
lobe of the thyroid gland, and, being joined by some branches from the lai-ynx
and trachea, terminates in the lower part of the internal jugular vein.
Veins of the Diploic.
The diploe of the cranial bones is channelled, in the adult, with a number of
tortuous canals, which are lined by a more or less complete layer of compact
tissue. The veins they contain are large and capacious, their walls being thin,
and formed only of epithelium, resting upon a layer of elastic tissue, and they
present, at irregular intervals, pouch-like dilatations, or culs de sac, which serve
as reservoirs for the blood. These are the veins of the diploe, and can only be
displayed by removing the outer table of the skull.
In adult life, as long as the cranial bones are distinct and separable, these veins
are confined to the particular bones; but in old age, when the sutures are united,
they communicate with each other, and increase in size. These vessels commu-
nicate, in the interior of the cranium, with the meningeal veins, and with the
sinuses of the dura mater; and on the exterior of the skull, with the veins of
the pericranium. In the cranium, they are divided into the frontal, which opens
4o6
VEINS
into the supra-orbital vein, by an aperture at the supra-orbital notch, the ante-
rior temporal, which is confined chiefly to the frontal bone, and opens into one of
the deep temporal veins, after escaping by an aperture in the great wing of the
217.— Veins of the Diploe, as displayed by the Eemoval of the
Outer Table of the Skull.
sphenoid, the posterior temporal, which is confined to the parietal bone, termi-
nates in the lateral sinus, by an aperture at the posterior inferior angle of the
parietal bone, and the occipital which is confined to the occipital bone, and opens
either into the occipital vein, or the occipital sinus.
Cerebral Veins.
The Cerebral Veins are remarkable for the extreme thinness of their coats,
from the muscular tissue in them being wanting, and for the absence of valves.
They may be divided into two sets, the superficial, which are placed on the
surface, and the deep veins, which occupy the interior of the organ.
The Superficial Cerebral Veins ramify upon the surface of the brain, being
lodged in the sulci, between the convolutions, a few running across the convolu-
tions. They receive branches from the substance of the brain, and terminate in
the sinuses. They are named from the position they occupy, superior, inferior,
internal, or external.
The Superior Cerebral Veins, seven or eight in number on each side, pass
forwards and inwards towards the great longitudinal fissure, where they receive
the internal cerebral veins, which return the blood from the convolutions of the
flat surface of the corresponding hemisphere; passing obliquely forwards, they
become invested with a tubular sheath of the arachnoid membrane, and open into
the superior longitudinal sinus, in the opposite direction to the course of the
blood.
The Inferior Anterior Cerebral Veins commence on the under surface of the
anterior lobes of the brain, and terminate in the cavernous sinuses.
The Inferior Lateral Cerebral Veins commence on the lateral parts of the
hemispheres and at the base of the brain: they unite to form from three to five
veins, which open into the lateral sinus from before backwards.
The Inferior Median Cerebral Veins, which are very large, commence at the
fore part of the under surface of the cerebrum, and from the convolutions of the
posterior lobe, and terminate in the straight sinus behind the venae Galeni.
ClilREBRAL.
407
The Deep Cerebral, or Ventricular Veins (venas Galeni), are two in number,
one from the right, the other from the left, ventricle. They are each formed
by two veins, the vena corporis striati, and the choroid vein. They pass back-
wards, parallel with one another, enclosed within the velum interpositum, and
pass out of the brain at the great transverse fissure, between the under surface
of the corpus callosum and the tubercula quadrigemina, and enter the straight
sinus.
The Vena Corporis Striati commences in the groove between the corpus stria-
tum and thalamus opticus, receives numerous veins from both of these parts, and
unites behind the anterior pillar of the fornix with the choroid vein, to form one
of the venffi Galeni.
The Choroid Vein runs along the whole length of the outer border of the
choroid plexus, receiving veins from the hippocampus major, the fornix and
corpus callosum, and unites, at the anterior extremity of the choroid plexus, with
the vein of the corpus striatum.
The Cerebellar Veins occupy the surface of the cerebellum, and are disposed
in three sets, superior, inferior, and lateral. The superior pass forwards and
inwards, across the superior vermiform process, and terminate in the straight
sinus: some open into the venae G-aleni. The inferior cerebellar veins, of large
size, run transversely outwards, and terminate by two or three trunks in the
lateral sinuses. The latei*al anterior cerebellar veins, terminate in the superior
petrosal sinuses.
Sinuses of the Dura Mater.
The sinuses of the dura mater are venous channels, analogous to the veins,
their outer coat being formed by the dura mater; their inner, by a continuation
of the serous membrane of the veins. They are twelve in number, and are
divided into two sets, i . Those situated at the upper and back part of the skull.
2. The sinuses at the base of the skull. The former are the
Superior longitudinal. Straight sinus.
Inferior longitudinal. Lateral sinuses.
Occipital sinuses.
218. — Vertical Section of the Skull, showing the Sinuses of the Dura Mater.
ForitTiien C'cecajti
The Superior Longitudinal Sinus occupies the attached margin of the falx
cerebri. Commencing at the crista Galli, it runs from' before backwards, groov-
ing the inner surface of the frontal, the adjacent margins of the two parietal.
4o8 VEINS.
and the superior division of the crucial ridge of the occipital bone, and terminates
by dividing into the two lateral sinuses. This sinus is triangular in form,
narrow in front, and gradually increasing in size as it passes backwards. On
examining its inner surface, it presents the internal openings of the cerebral
veins, the apertures of which are, for the most part, directed from behind for-
wards, and chiefly open at its back part, their orifices being concealed by fibrous
areolae ; numerous fibrous bands are also seen {chordce Willisi), which extend trans-
versely across its inferior angle; and lastly, some small, white, projecting bodies,
the glandulse Pacchioni. This sinus receives the superior cerebral veins,
numerous veins from the diploe and dura mater, and, at the posterior extremity of
the sagittal suture, the parietal veins from the pericranium.
The point where the superior longitudinal and lateral sinuses are continuous is
called the conjluence of the sinuses, or the torcular HeropMli. It presents a cout
siderable dilatation, of very irregular form, and is the point of meeting of six
sinuses, the superior longitudinal, the two lateral, the two occipital, and the
straight.
The Inferior Longitudinal Sinus, more correctly described as the inferior
longitudinal vein, is contained in the posterior part of the free margin of the falx
cerebri. It is of a circular form, increases in size as it passes backwards, and
terminates in the straight sinus. It receives several veins from the falx cerebri,
and occasionally a few from the flat surface of the hemispheres.
The Straight Sinus is situated at the line of junction of the falx cerebri with
the tentorium. It is triangular in form, increases in size as it proceeds back-
wards, and runs obliquely downwards and backwards from the termination of the
inferior longitudinal sinus to the torcular Herophili. Besides the inferior lon-
gitudinal sinus, it receives the ven^ Galeni, the ^ inferior median cerebral veins,
and the superior cerebellar. A few transverse bands cross its interior.
The Lateral Sinuses are of large size, and situated in the attached margin of
the tentorium cerebelli. They commence at the torcular Heroph|ili, and passing
horizontally outwards to the base of the petrous portion of the temporal bone,
curve downwards and inwards on each side to reach the jugular foramen, where
they terminate in the internal jugular vein. Each sinus rests, in its course, upon
the inner surface of the occipital, the posterior inferior angle of the parietal, the
mastoid portion of the temporal, and on the occipital again just before its termi-
nation. These sinuses are of unequal size, the right being the larger, and they
increase in size as they proceed from behind forwards. The horizontal portion is
of a triangular form, the curved portion semi-cylindrical; their inner surface is
smooth, and not crossed by the fibrous bands found in the other sinuses. These
sinuses receive blood from the superior longitudinal, the straight, and the occipital
sinuses; and in front they communicate with the superior and inferior petrosal.
They communicate with the veins of the pericranium by means of the mastoid and
posterior condyloid veins, and they receive the inferior cerebral and inferior cere-
bellar veins, and some from the diploe.
The Occipital Sive the smallest of the cranial sinuses. They are usually two in
number, and situated in the attached margin of the falx cerebelli. They commence
by several small veins around the posterior mai'gin of the foramen magnum, which
communicate with the posterior spinal veins, and terminate by separate openings
(sometimes by a single aperture) in the torcular Herophili.
The sinuses at the base of the skull are the
Cavernous. Inferior petrosal.
Circular. Superior petrosal.
Transverse.
The Cavernous Sinuses are named from their presenting a reticulated structure.
They are two in number, of large size, and placed one on each side of the sella
Turcica, extending from the sphenoidal fissure to the apex of the petrous portion
of the temporal bone: they receive anteriorly the ophthalmic vein through the
SINUSES OF THE DURA MATER.
409
sphenoidal fissure, communicate behind with the petrosal sinuses, and with each
other by the circular and transverse sinuses. On the inner wall of each sinus is
found the internal carotid artery, accompanied by filaments of the carotid plexus,
and by the sixth nerve; and on its outer wall, the third, fourth, and ophthalmic
nerves. These parts are separated from the blood flowing along the sinus by the
lining membrane, which is continuous with the inner coat of the veins. The
219.— The Sinuses at the Base of the Skull.
cavity of the sinus, which is larger behind than in front, is intersected by fila-
ments of fibrous tissue and small vessels. The cavernous sinuses receive the inferior
anterior cerebral veins; they communicate with the lateral sinuses by means of
the superior and inferior petrosal, and with the facial vein through the
ophthalmic.
The Ophthalmic is a large vein, which connects the frontal at the inner angle
of the orbit with the cavernous sinus; it pursues the same course as the ophthal-
mic artery, and receives branches corresponding to those derived from that vessel.
Forming a short single trunk, it passes through the inner extremity of the
sphenoidal fissure, and terminates in the cavernous sinus.
The Circular Sinus completely surrounds the pituitary body, and communicates
on each side with the cavernous sinuses. Its posterior half is larger than the an-
terior; and in old age it is more capacious than at an early period of life. It
receives veins from the pituitary body, and from the adjacent bone and dura
mater.
The Inferior Petrosal Sinus is situated in the groove formed by the junction of
the inferior border of the petrous portion of the temporal with the basilar process of
the occipital. It commences in front at the termination of the cavernous sinus,
and opens behind, at the jugular foramen, forming with the lateral sinus the com-
mencement of the internal jugular vein. These sinuses are semi-cylindrical
in form.
The Transverse Sinus is placed transversely across the fore part of the
basilar process of the occipital bone serving to connect the two inferior petrosal
410
VEINS
Z20. — ^The Superficial Veins of tlie
Upper Extremity.
and cavernous sinuses. A second is occasionally found opposite the foramen
magnum.
The Superior Petrosal Sinus is situated along the upper border of the petrous
portion of the temporal bone, in the front
part of the attached margin of the tentorium.
It is small and narrow, and connects together
the cavernous and lateral sinuses at each
side. It receives a cerebral vein (inferior
lateral cerebral) from the under part of
the middle lobe, and a cerebellar vein (ante-
rior lateral cerebellar) from the anterior
border of the cerebellum.
VEINS OF THE UPPER EXTREMITY.
The veins of the upper extremity are
divided into two sets: I. The superficial
veins. 2. The deep veins.
The Superficial Veins are placed imme-
diately beneath the integument between the
two layers of superficial fascia; they com-
mence in the hand chiefly on its dorsal
aspect, where they form a more or less
complete arch.
The Deep Veins accompany the arteries,
and constitute the venas comites of those
vessels.
Both sets of vessels are provided with
valves, which are more numerous in the
deep than in the superficial.
The superficial veins of the upper extre-
mity are the
Anterior ulnar.
Posterior ulnar.
Basilic.
Radial.
Cephalic.
Median.
Median basilic.
Median cephalic.
The Anterior Ulnar Vein commences on
the anterior surface of the wrist and ulnar
side of the hand, and ascends along the
inner side of the fore-arm to the bend of
the elbow, where it joins with the posterior
ulnar vein, to form the basilic. It commu-
nicates with branches of the median vein in
front, and with the posterior ulnar behind.
The Posterior Ulnar Vein commences on
the posterior surface of the ulnar side of the
hand, and from the vein of the little finger
(vena salvatella), situated over the fourth
metacarpal space. It ascends on the poste-
rior surface of the ulnar side of the fore-
arm, and just below the elbow unites with
the anterior ulnar vein to form the basilic.
OF THE UPPER EXTREMITY. 411
The Basilic is a vein of considerable size, formed by tlie coalescence of the
anterior and posterior ulnar veins; ascending along the inner side of the elbow, it
receives the median basilic vein, and passing upwards along the inner side of the
arm, pierces the deep fascia, and ascends in front of the brachial artery, termi-
nating either in one of the venas comites of that vessel, or in the axillary vein.
The Radial Vein commences from the dorsal surface of the thumb, index finger,
and radial side of the hand, by branches which communicate with the vena salva-
tella. They form by their union a large vessel, which ascends along the radial
side of the fore-arm, receiving numerous branches from both its surfaces. At the
bend of the elbow it receives the median cephalic, when it becomes the cephalic
vein.
The Cephalic Vein ascends along the outer border of the Biceps muscle, to the
upper third of the arm; it then passes in the interval between the Pectoralis major
and Deltoid muscles, accompanied by the descending branch of the thoracica acro-
mialis artery, and terminates in the axillary vein just below the clavicle. This
vein is occasionally connected with the external jugular or subclavian, by a branch
which passes from it upwards in front of the clavicle.
The Median Vein collects the blood from the superficial structures in the palmar
surface of the hand and middle line of the fore-arm, communicating with the an-
terior ulnar and radial veins. At the bend of the elbow, it receives a branch of
communication from the deep veins, accompanying the brachial artery, and divides
into two branches, the median cephalic and median basilic, which diverge from
each other as they ascend.
The Median Cephalic, the smaller of the two, passes outwards in the groove
between the Supinator longus and Biceps muscles, and joins with the cephalic
vein. The branches of the external cutaneous nerve pass behind this vessel.
The Median Basilic vein passes obliquely inwards, in the groove between the
Biceps and Pronator radii teres, and joins with the basilic. This vein passes
in front of the brachial artery, from which it is separated by a fibrous expansion,
given off from the tendon of the Biceps to the fascia covering the Flexor muscles.
Filaments of the internal cutaneous nerve pass in front as well as behind this
vessel.
The Deep Veins of the Upper Extremity follow the course of the arteries,
forming their venee comites. They are generally two in numbei', one lying on each
side of the corresponding artery, and they are connected at intervals by short
transverse branches.
There are two digital veins accompanying each artery along the sides of the
fingers; these, uniting at their base, pass along the interosseous spaces in the palm,
and terminate in the two superficial palmar veins. Branches from these vessels
on the radial side of the hand accompany the superficialis volse, and on the uhiar
side, terminate in the deep ulnar veins. The deep ulnar veins, as they pass in
front of the wrist, communicate with the interosseous and superficial veins, and
unite at the elbow, with the deep radial veins, to form the ven» comites of the
brachial artery.
The Interosseous Veins accompany the anterior and posterior interosseous
arteries. The anterior interosseous veins commence in front of the wi'ist, where
they communicate with the deep radial and ulnar veins; at the upper part of the
fore-arm they receive the posterior interosseous veins, and terminate in the ven«
comites of the ulnar artery.
The Deep Palmar Veins accompany the deep palmar arch, being formed by
branches which accompany the ramifications of this vessel. They communicate
with the superficial palmar veins at the inner side of the hand; and on the outer
side, terminate in the venas comites of the radial artery. At the wrist, they receiva
a dorsal and a palmar branch from the thumb, and unite with the deep radial veins.
Accompanying the radial artery, these vessels terminate in the vense comites of the
brachial artery.
The Brachial Veins are placed one on each side of the brachial artery, receiving
412 VEINS
branches corresponding with those given off from this vessel; at the lower margin
of the axilla they miite with the basilic to form the axillaiy vein.
The deep veins have numerous anastomoses, not only with each other, but also
with the supei'ficial veins.
Axillary Vein.
The axillary vein is of large size and formed by the continuation upwards of
the basilic vein. It commences at the lower part of the axillary space, and
increasing in size as it ascends, by receiving branches corresponding with those of
the axillary artery, terminates immediately beneath the clavicle at the outer mar-
gin of the first rib, and becomes the subclavian vein. This vessel is covered in
front by the Pectoral muscles and costo-coracoid membrane, and lies on the tho-
racic side of the axillary artery. Opposite the Subscapularis, it is joined by a
large vein, formed by the junction of the ven^ comites of the brachial; and near
its termination it receives the cephalic vein. This vein is provided with valves
at the point where it is joined by the cephalic and basilic veins.
Subclavian Vein.
The subclavian vein, the continuation of the axillary, extends from the outer
margin of the first rib to the inner end of the sterno- clavicular articulation,
where it unites with the internal jugular, to form the vena innominata. It is
in relation, in front, with the clavicle and Subclavius muscle; behind, with the
subclavian artery, from which it is separated internally by the Scalenus anticus
and phrenic nerve. Below, it rests in a depression on the first rib and upon the
pleura. Above, it is covered by the cervical fascia and integument.
The subclavian vein occasionally rises in the neck to a level with the third part
of the subclavian artery, and in two instances, has been seen passing with this
vessel behind the Scalenus anticus. This vessel is provided with valves near its
termination in the innominate.
Branches. It receives the external and anterior jugular veins and a small branch
from the cephalic, outside the Scalenus; and on the inner side of this muscle, the
vertebral and internal jugular veins.
The Vertebral Vein commences by numerous small branches in the occipital
region, from the deep muscles at the upper and back part of the neck, passes out-
wards, and enters the foramen in the transverse process of the atlas, and descends
by the side of the vertebral artery, in the canal formed by the transverse processes
of the cervical vertebrte. Emerging from the foramen in .the transverse process of
the sixth cervical, it terminates at the root of the neck in the subclavian vein near
its junction with the vena innominata. This vein, in the lower part of its course,
occasionally divides into two branches, one emerges with the artery at the sixth
cervical vertebra; the other escapes through the foramen in the seventh cervical.
Branches. This vein receives in its course the posterior condyloid vein,
muscular branches from the muscles in the prevertebral region; dorsi-spinal
veins, from the back part of the cervical portion of the spine; meningo-rachidian
veins, from the interior of the spinal canal; and lastly, the ascending and deep
cervical veins.
Innominate Veins.
The vena3 innominatse (fig. 22 1) are two large trunks, placed one on each side of
the root of the neck, and formed by the union of the internal jugular and subcla-
vian veins of the corresponding side.
The Right Vena Innominata is a short vessel, about an inch and a half in length,
which commences at the inner end of the clavicle, and passing almost vertically
downwards, joins with the left vena innominata just below the cartilage of the first
rib, to form the superior vena cava. It lies sujjerficial and external to the arteria
innominata; on its right side the pleura is interposed between it and the apex of the
lung. This vein at its angle of junction with the subclavian, receives the right
INNOMINATE.
413
lympliatic duct; and lower down, the right internal mammary, right inferior thy-
roid, and right superior intercostal veins.
The Left Vena Innomi-
nata, about three mches in
length, and larger than the
right, passes obliquely
from left to right across
the upper and front part of
the chest, to unite with its
fellow of the opposite side,
forming the superior vena
cava. It is in relation in
front, with the sternal end
of the left clavicle, the left
sterno-clavicular articula-
tion, and with the first
piece of the sternum, from
which it is separated by the
Sterno-hyoid and Sterno-
thyroid muscles, the thy-
mus glands or its remains,
and some loose areolar tis-
sue. Behind, it lies across
the roots of the three large
arteries arising from the
arch of the aorta. This
vessel, at its commence-
ment, receives the thoracic
duct; it is joined also by
the left inferior thyroid,
left internal mammary, and
the left superior intercos-
tal veins, and occasionally
some thymic and pericar-
diac veins. There are no
valves in the venae innomi-
natfe.
Peculiarities. Sometimes
the innominate veins open
separately into the right auri-
cle; in such cases the right
vein takes the ordinary course
of the supei'ior vena cava, but
the left vein, after communi-
cating by a small branch with
the right one, passes in front
of the root of the left lung,
and turning to the back of
the heart, receives the cardiac
veins, and terminates in the
back of the right auricle.
This occasional condition of
the veins in the adult, is a
regular one in the foetus at an
early period, and the two ves-
sels are persistent in birds
and some mammalia. The
subsequent changes which
take place in these vessels are
the following. The communi-
cating branch between the
221. — The Vense Cavse and Azygos Veins,
with their Formative Branches.
ninnorJi/a
S'lpepior Tlii/i'oiil
rnal Ju^iila/r'
414
VEINS.
two trunks enlarges and forms the future left innominate vein ; tlie remaining part of tlie
left trunk is obliterated as far as the heart, where it remains pervious, and forms the coro-
nary sinus ; a remnant of the obliterated vessel is seen in adult life as a fibrous band
passing along the back of the left auricle and in front of the root of the left lung, called
by Mr, Marshall, the vestigial fold of the pericardium.
The Internal Mammary Veins, two in number to each artery, follow the
course of that vessel, and receive branches corresponding with those derived
from it. The two veins unite into a single trunk, which terminates in the inno-
minate vein.
The Inferior Thyroid Veins, two, frequently three or four in number, arise
in the venous plexus, on the thyroid body, communicating with the middle and
superior thyroid veins. The left one, descends in front of the trachea, behind
the Sterno-thyroid muscles, communicating with its fellow by transverse branches,
and terminates in the left vena innominata. Th6 right one, which is placed a
little to the right of the median line, opens into the right vena innominata, just
at its junction with the superior cava. These veins receive tracheal and inferior
laryngeal branches, and are provided with valves at their termination in the
innominate veins.
The Superior Intercostal Veins return the blood from the upper intercostal
spaces.
The right superior intercostal, much smaller than the left, closely corresponds
with the superior intercostal artery, receiving the blood from the first, or first
and second intercostal spaces, and terminates in the right vena innominata.
Sometimes it passes down, and opens into the vena azygos major.
The left superior intercostal is always larger than the right, but varies in
size in different subjects, being small when the left upper azygos vein is large,
and vice versa. It is usually formed by branches from the two or three upper
intercostal spaces, and, passing across the arch of the aorta, terminates in the
left vena innominata. The left bronchial vein opens into it.
Superior Vena Cava.
The Superior Vena Cava receives the blood which is conveyed to the heart
from the whole of the upper half of the body. It is a short trunk, varying
from two inches and a half to three inches in length, formed by the junction of
the two venae innominata. It commences immediately below the cartilage of the
first rib on the right side, and, descending vertically downwards, enters the
pericardium, and terminates in the upper part of the right auricle. In its
course, it describes a slight curve, the convexity of which is turned to the right
side.
Relations. The part external to the pericardium is in relation, in front, with the
thoracic fascia, which separates it from the thymus gland, and from the sternum;
behind, with the trachea, from which it is separated by numerous lymphatic glands.
On its right side, with the right phrenic nerve and the right lung; on its left side,
with the arch of the aorta. The portion contained within the pericardium, is
covered by the serous layer of that membrane, in its anterior three-fourths. It
is in relation, behind, with the right pulmonary artery, and right superior pul-
monary veins; on the left side, with the aorta. It receives the vena azygos
major, just before it enters the pericardium, and several small veins from the
mediastinum and pericardium. The superior vena cava has no valves.
Azygos Veins.
The Azygos Veins connect together the superior and inferior venae cav£e,
supplying the place of these vessels in that part of the trunk in which they are
deficient, on account of their connection with the heart.
The larger, or Right Azygos Vein, commences opposite the first or second
lumbar vertebra, by receiving a branch from the right lumbar veins; sometimes
by a branch from the renal vein, or from the inferior vena cava. It enters the
AZYGOS; SPINAL. 415
thorax through the aortic opening in the Diaphragm, and passes along the right side
of the vertebral column to the third dorsal vertebra, where it arches forward, over
the root of the right lung, and terminates in the superior vena cava, just before
that vessel enters the pericardium. Whilst passing through the aortic opening of
the Diaphragm, it lies with the thoracic duct on the right side of the aorta; and
in the thorax it lies upon the intercostal arteries, on the right side of the aorta
and thoracic duct, and covered by the pleura.
Branches. It receives nine or ten lower intercostal veins of the right side, the
vena azygos minor, several oesophageal, mediastinal, and vertebral veins; near its
termination, the right bronchial vein; and it is occasionally connected with the
right superior intercostal vein. A few imperfect valves are found in this vein,
but its branches are provided with complete valves.
The intercostal veins on the left side, below the two or three upper intercostal
spaces, usually form two trunks, named the left lower, and the left upper, azygos
veins.
The Left lower, or Smaller Azygos Vein, commences in the lumbar region, by
a branch from one of the lumbar veins, or from the left renal. It passes into the
thorax, through the left crus of the Diaphragm, and, ascending on the left side of
the spine, as high as the sixth or seventh vertebra, passes across the column,
behind the aorta and thoracic duct, to terminate in the right azygos vein. It
receives the four or five lower intercostal veins of the left side, and some oesopha-
geal and mediastinal veins.
The Left Upper Azygos, varies according to the size of the left superior
intercostal. It receives veins from the intercostal spaces between the superior
intercostal vein, and highest branch of the left lower azygos. They are usually
two or three in number, and join to form a trunk which ends in the right azygos
vein, or in the left lower azygos. When this vein is small, or altogether want-
ing, the left superior intercostal vein will extend as low as the fifth or sixth
intercostal space.
The Bronchial Veins return the blood from the substance of the lungs; that
of the right side opens into the vena azygos major, near its termination; that of
the left side, in the left superior intercostal vein.
The Spinal Veins.
The numerous venous plexuses placed upon and within the spine, may be
arranged into four sets.
1. Those placed on the exterior of the spinal column, the dorsi-spinal veins.
2. Those situated in the interior of the spinal canal, between the vertebra and
the theca vertebralis (meningo-rachidian veins).
3. The veins of the bodies of the vertebrfe.
4. The veins of the spinal cord (medulli spinal).
1. The Dor si- Spinal Veins commence by small branches, which receive their
blood from the integument of the back of the spine, and from the muscles in the
vertebral grooves. They form a complicated net-work, which surrounds the
spinous processes, laminae, and the transverse and articular processes of all the
vertebrae. At the bases of the transverse processes, they communicate, by means
of ascending and descending branches, with the veins surrounding the contiguous
vertebras, and with the veins in the interior of the spine, in the intervals between
the arches of the vertebrje, perforating the ligamenta subflava, and terminate in
the vertebral vein in the neck, in the intercostal veins in the thorax, in the
lumbar and sacral veins in the loins and pelvis.
2. The veins contained in the interior of the spinal canal, are situated
between the theca vertebralis and the vertebrae. They consist of two longitudinal
plexuses, one of which runs along the posterior surface of the bodies of the
vertebra?, throughout the entire length of the spinal canal (anterior longitudinal
4i6
VEINS.
spinal veins), receiving the veins belonging to the bodies of the vertebras (vense
basis vertebrarum). The other plexus is placed on the inner, or anterior surface
^ o i.- J? -n 1 T7 i. -u^^ of the lamina of the vertebrae.
a22. — Transverse Section of a Dorsal Vertebra, , n i ,i
showing the Spinal Veins. They also extend along the
entire length of the spinal
canal, and are called the
posterior longitudinal spinal
veins.
The Anterior Longitudinal
Spinal Veins consist of two
large, tortuous venous canals,
which extend along the whole
length of the vertebral co-
lumn, from the foramen mag-
num to the base of the coccyx,
being placed one on each side
of the posterior surface of the
bodies of the vertebra, exter-
nal to the posterior common
ligament. These veins com-
municate together opposite
each vertebra, by transverse
trunks, which pass beneath
the ligament, and receive the large venas basis vertebrarum, from the interior
of the body of each vertebra. The anterior longitudinal spinal veins are least
developed in the cervical and sacral regions. They are not of uniform size
throughout, being alternately enlarged and constricted. At the intervertebral
foramina they communicate
223. — Vertical Section of two Dorsal Vertebrae, with the dorsi-spinal veins,
showing the Spinal Veins. and with the vertebral vein in
the neck, with the intercostal
veins in the dorsal region,
and with the lumbar and sac-
ral veins in the corresponding
regions.
The Posterior Longitudi-
nal Spinal Veins, smaller
than the anterior, are situated
one on either side, between
the inner surface of the la-
minae and the theca vertebra-
lis. They communicate (like
the anterior), opposite each
vertebra, by transverse trunks ;
and with the anterior longitudinal veins, by lateral transverse branches, which
pass from behind forwards. These veins, at the intervertebral foramina, join
with the dorsi-spinal veins.
3. The Veins of the Bodies of the Vertehrce (venae basis vertebrarum), emerge
from the foramina on their posterior surface, and join the transverse trunk
connecting the anterior longitudinal spinal veins. They are contained in large,
tortuous channels, in the substance of the bones, similar in every respect to those
found in the diploe of the cranial bones. These canals lie parallel to the upper
and lower surface of the bones, arise from the entire circumference of the ver-
tebra, communicate with veins which enter through the foramina, on the anterior
surface of the bodies, and converge to the principal canal, which is sometimes double
towards its posterior part. They become greatly developed in advanced age.
4. The Veins of the Spinal Cord (medulli spinal), consist of a minute tortuous
OF THE LOWER EXTREMITY.
417
venous plexus, which covers the entire surface of the cord, being situated
between the pia-mater and araclmoid. These vessels emerge chiefly from tlie
posterior median furrow, and are largest in the lumbar region. Near the base of
the skull they unite, and form two or three small trunks, which communicate
with the vertebral veins, and then terminate in
the inferior cerebellar veins, or in the petrosal
sinuses. Each of the spinal nerves is accompanied
by a branch as far as the intervertebral foramina,
where they join the other veins from the spinal
canal. There are no valves in the spinal veins.
224. — The Internal or Long Sa-
phenous Vein and its Branches.
^V
VEINS OF THE LOWER EXTREMITY.
The veins of the lower extremity are divided,
like those of the upper, into two sets, superficial
and deep: the superficial veins being placed be-
neath the integument, between the two layers of
superficial fascia; the deep veins accompanying
the arteries, and forming the venge comites of
those vessels. Both sets of veins are provided
with valves, which are more numerous in the deep
than in the superficial set. These valves are also
more numerous in the lower than in the upper
limbs.
The Superficial Veins of the lower extremity
are the internal or long saphenous, and the ex-
ternal or short saphenous.
The Internal Saphenous Vein (fig. 224) com-
mences from a minute plexus, which covers the
dorsum and inner side of the foot; it ascends in
front of the inner ankle, and along the inner side
of the leg, behind the inner margin of tlie tibia,
accompanied by the internal saphenous nerve. At
the knee it passes backwards behind the inner
condyle of the femur, ascends along the inside of
the thigh, and, passing through the saphenous
opening in the fascia lata, terminates in the femo-
ral vein, an inch and a half below Poupart's liga-
ment. This vein receives in its course cutaneous
branches from the leg and thigh, and at the saphe-
nous opening, the superficial epigastric, superficial
circumflex iliac, and external pudic veins. The
veins from the inner and back part of the thigh
frequently unite to form a large vessel, which
enters the main trunk near the saphenous opening,
and sometimes those on the outer side of the thigh
join to form a large branch; so that occasionally
three large veins are seen converging from different
parts of the thigh towards the saphenous opening.
The internal saphena communicates in the foot
- with the internal plantar vein ; in the leg, with the
posterior tibial veins, by branches which perforate
the tibial origin of the Soleus muscle, and also
with the anterior tibial veins; at the knee, with
the articular veins; in the thigh, with the femoral
vein by one or more branches. The valves in this
E E
4i8
VEINS.
225.-
-External, or Short Saphe-
nous Vein.
vein vary from two to six in number; they are more numerous in the thigh than
in the leg.
The External or Short Saphenous Vein is formed by branches which collect the
blood from the dorsum and outer side of the foot;
it passes behind the outer ankle, and along the
outer border of the tendo Achillis, across which
it passes at an acute angle to reach the middle
line of the posterior aspect of the leg. Ascend-
ing directly upwards, it perforates the deep fascia
in the lower part of the popliteal space, and ter-
minates in the popliteal vein, between the heads
of the Gastrocnemius muscle. It is accompanied
by the external saphenous nerve. It receives nu-
merous large branches from the back part of the
leg, and communicates with the deep veins on the
dorsum of the foot, and behind the outer malleolus.
This vein has only two valves, one of which is
always found near its termination in the popliteal
vein.
The Deep Veins of the lower extremity accom-
pany the arteries and their branches, and are
called the vence comites of those vessels.
The external and internal plantar veins unite to
form the posterior tibial. They accompany the
posterior tibial artery, and are joined by the pero-
neal veins.
The Anterior Tibial Veins are formed by a
continuation upwards of the venae dorsales pedis.
They perforate the interosseous membrane at the
upper part of the leg, and form, by their junction
with the posterior tibial, the popliteal vein.
The valves in the deep veins are very nu-
merous.
Popliteal Vein.
The popliteal vein is formed by the junction of
the venje comites of the anterior and posterior
tibial vessels; it ascends through the popliteal
space to the tendinous aperture in the Adductor
niagnus, where it becomes the femoral vein. In
the lower part of its course it is placed internal
to the artery; between the heads of the Gastroc-
superficial to that vessel, but above the knee-joint it is close to its
It receives the sural veins from the Gastrocnemius muscle, the
articular veins, and the external saphenous. The valves in this vein are usually
four in number.
nemms it is
outer side.
Femoral Vein.
The femoral vein accompanies the femoral artery through the upper two-thirds
of the thigh. In the lower part of its course it lies external to the artery; higher
up it is behind it; and beneath Poupart's ligament it lies to its inner side, and on
the same plane as that vessel. It receives numerous muscular branches; the pro-
funda femoris joins it about an inch and a half below Poupart's ligament, and near
its termination the internal saphenous vein. The valves in this vein are four or
five in number.
ILIAC. 419
External Iliac Vein.
The external iliac vein commences at the termination of the femoral, beneath
the crural arch, and passing upwards along the brim of the pelvis, terminates
opposite the sacro-iliac symphysis, by uniting with the internal iliac to foi'm the
common iliac vein. On the right side, it lies at first along the inner side of the
external iliac artery; but as it passes upwards, gradually inclines behind it. On
the left side, it lies altogether on the inner side of the artery. It receives, imme-
diately above Poupart's ligament, the epigastric and circumflex iliac veins. It
has no valves.
Internal Iliac Vein.
The internal iliac vein is formed by the venae comites of the branches of the
internal iliac artery, the umbilical arteries excepted. It receives the blood from
the exterior of the pelvis by the gluteal, sciatic, internal pudic, and obturator
veins; and from the organs in the cavity of the pelvis by the hgemorrhoidal and
vesico-prostatic plexuses in the male, and the uterine and vaginal plexuses in the
female. The vessels forming these plexuses are remarkable for their large size,
their frequent anastomoses, and the number of valves which they contain. The
internal iliac vein lies at first on the inner side and then behind the internal iliac
artery, and terminates opposite the sacro-iliac articulation, by uniting with the
external iliac, to form the common iliac vein. This vessel has no valves.
The Hcemorrhoidal Plexus surrounds the lower end of the rectum, being
formed by the superior hcemorrhoidal veins, branches of the inferior mesenteric,
and the middle and inferior hgemorrhoidal, which terminate in the internal iliac.
The portal and general venous systems have a free communication by means of
the branches composing this plexus.
The Vesico-prostatic Plexus surrounds the neck and base of the bladder and
prostate gland. It communicates with the haemorrhoidal plexus behind, and re-
ceives the great dorsal vein of the penis, which enters the pelvis beneath the
sub-pubic ligament. This plexus is supported upon the sides of the bladder by a
reflection of the pelvic fascia. These veins are very liable to become varicose,
and often contain hard earthy concretions, called phleholites.
The Dorsal Vein of the Penis is a vessel of large size, which returns the blood
from the body of this organ. At first it consists of two branches, which are con-
tained in the groove on the dorsum of the penis, and receives veins from the
glans, the corpus spongiosum, and numerous superficial veins; these unite near the
root of the penis into a single trunk, which pierces the triangular ligament beneath
the pubic arch, and divides into two branches, which enter the prostatic plexus;
The Vaginal Plexus surrounds the mucous membrane of the vagina, being
especially developed at the orifice of this canal; it communicates with the vesical
plexus in front, and with the haemorrhoidal plexus behind.
The Uterine Plexus is situated along the sides and superior angles of the
uterus, receiving large venous canals (the uterine sinuses) from its substance. The
veins composing this plexus anastomose frequently with each other, and some of
them communicate with the ovarian veins. They are not tortuous like the arteries.
Common Iliac Vein.
Each common iliac vein is formed by the union of the external and internal
iliac veins in front of the sacro- vertebral articulation; passing obliquely up-
wards towards the right side, they terminate upon the intervertebral substance
.between the fourth and fifth lumbar vertebrae, where they unite at an acute angle
to form the inferior vena cava. The right common iliac is shorter than the left,
nearly vertical in its direction, and ascends behind and then to the outer side of its
corresponding artery. The left common iliac, longer and more oblique in its course,
is at first situated at the inner side of the corresponding artery, and then behind
the right common iliac. Each common iliac receives the ilio-lumbar, and some-
E E 2
420 VEINS.
times the lateral sacral veins. The left one receives, in addition, the middle sacral
vein. No valves are found in these veins.
The Middle Sacral Vein accompanies its corresponding artery along the front
of the sacrum, and terminates in the left common iliac vein; occasionally in the
commencement of the inferior vena cava.
Peculiarities. The left common iliac vein, instead of joining with the right one in its
usual position, occasionally ascends on the left side of the aorta as high as the kidney,
where, after receiving the left renal vein, it crosses over the aorta, and then joins with the
right vein to form the vena cava. In these cases, the two common iliacs are connected
by a small communicating branch at the spot where they are usually united.
Inferior Vena Cava.
The inferior vena cava returns to the heart the, blood from all the parts below
the Diaphragm. It is formed by the junction of the two common iliac veins on
the right side of the intervertebral substance, between the fourth and fifth lumbar
vertebra3. It passes upwards along the front of the spine, on the right side of the
aorta, and having reached the under surface of the liver, is contained in a groove
in its posterior border. It then perforates the tendinous centre of the Diaphragm,
enters the pericardium, where it is covered by its serous layer, and terminates in
the lo ver and back part of the right auricle. At its termination in the auricle,
it is provided with a valve, the Eustachian, which is of large size during foetal
life.
Relations. In front, from below upwards, with the mesentery, transverse por-
tion of the duodenum, the pancreas, portal vein, and the posterior border of the
liver, which partly and occasionally completely surrounds it; behind, it rests upon
the vertebral column, the right crus of the diaphragm, the right renal and lumbar
arteries; on the left side, it is in relation with the aorta. It receives in its course
the following branches:
Lumbar. Supra-renal.
Right spermatic. Phrenic.
Renal. Hepatic.
Peculiarities. In Position. This vessel is sometimes placed on the left side of the aorta,
as high as the left renal vein, after receiving which, it crosses over to its usual position on
the right side ; or it may be placed altogether on the left side of the aorta, as far upwards
as its termination in the heart : in such cases, the abdominal and thoracic viscera, together
with the great vessels, are all transposed.
Point of Termination. Occasionally the inferior vena cava joins the right azygos vein,
which is then of large size. In such cases, the superior cava receives the whole of the
blood from the body before transmitting it to the right auricle, the blood from the hepatic
veins excepted, these vessels terminating directly in the right auricle.
The Lumbar Veins, three or four in number on each side, collect the blood by
dorsal branches from the muscles and integument of the loins, and by abdominal
branches from the walls of the abdomen, where they communicate with the
epigastric veins. At the spine, they receive branches from the spinal plexuses, and
then pass forwards round the sides of the bodies of the vertebrae beneath the Psoas
magnus, and terminate at the back part of the inferior cava. The left lumbar veins
are longer than the right, and pass behind the aorta. The lumbar veins communicate
with each other by branches which pass in front of the transverse processes.
Occasionally two or more of these veins unite to form a single trunk, the ascending
lumbar, which serves to connect the common iliac, ilio-lumbar, lumbar, and azygos
veins of the corresponding side of the body.
The Spermatic Veins emerge from the back of the testis, and receive branches
from the epididymis; they form a branched and convoluted plexus, called the
spermatic plexus (plexus pampiniformis), below the abdominal ring: the vessels
composing this plexus are very numerous, and ascend along the cord in front of
the vas deferens; having entered the abdomen, they coalesce to form two branches,
which ascend on the Psoas muscle, behind the peritoneum, lying one on each
INFERIOR CAVA.
421
side of the spermatic artery, and unite to form a single vessel, which opens on
the right side in the inferior vena cava, piercing this vessel obliquely; on the left
side in the left renal vein, terminating at right angles with this vein. The sper-
matic veins are provided with valves. The left spermatic vein passes behind the
sigmoid flexure of the colon; this circumstance, as well as the indirect communi-
cation of the vessel with the vena cava, may serve to explain the more frequent
occurrence of varicocele on the left side.
The Ovarian Veins are analogous to the spermatic in the male; they form a
plexus near the ovary, and in the broad ligament and Fallopian tube, communi-
cating with the uterine plexus. They terminate as in the male. Valves are
occasionally found in these veins. These vessels, like the uterine veins, become
much enlarged during pregnancy.
The Renal Veins are of large size, and placed in front of the divisions of
the renal arteries. The left is longer than the right, and passes in front of the
aorta, just below the origin of the superior mesenteric artery. It receives the
left spermatic vein. It usually opens into the vena cava, a little higher than
the right.
The Supra-Renal Vein terminates, on the right side, in the vena cava; on
the left side, in the left renal or phrenic vein.
The Phrenic Veins follow the course of the phrenic arteries. The two supe-
rior, of small size, accompany the corresponding nerve and arteiy; the right
terminating opposite the junction of the two venee innominataj, the left in the
left superior intercostal or left internal mammary. The two inferior phrenic veins
follow the course of the inferior phrenic arteries, and terminate, the right in the
inferior vena cava, the left in the left renal vein.
The Hepatic Veins commence in the substance of the liver, in the capillary
terminations of the vena portte: these branches, gradually uniting, form three
large veins, which converge towards the posterior border of the liver, and open
into the inferior vena cava, whilst that vessel is situated ua the groove at the
back part of this organ. Of these three veins, one from the right, and another
from the left lobes, open obliquely into the vena cava; that from the middle of the
organ and lobus Spigelii having a straight course. The hepatic veins run singly,
and are in direct contact with the hepatic tissue. They are destitute of valves.
Portal System of Veins.
The portal venous system is composed of four large veins, which collect the
venous blood from the viscera of digestion. The trunk formed by their union
(vena portee) enters the liver, ramifies throughout its substance, and its branches
again emerging from that organ as the hepatic veins, terminate in the inferior
vena cava. The branches of this vein are in all cases single, and destitute of
valves.
The veins forming the portal system are the
Inferior mesenteric. Splenic.
Superior mesenteric. Gastric.
The Inferior Mesenteric Vein returns the blood from the rectum, sigmoid
flexure, and descending colon, corresponding with the ramifications of the branches
of the inferior mesenteric artery. Ascending beneath the peritoneum in the
lumbar region, it passes behind the transverse portion of the duodenum and pan-
creas, and terminates in the splenic vein. Its hasmorrhoidal branches inosculate
with those of the internal iliac, and thus establish a communication between the
.portal and the general venous system.
The Superior Mesenteric Vein returns the blood from the small intestines, and
from the coecum and ascending and transverse portions of the colon, corresponding
with the distribution of the branches of the superior mesenteric artery. The
large trunk formed by the union of these branches ascends -along the right side and
in front of the corresponding artery, passes in front of the transverse portion of
422
VEINS.
the duodenum, and unites behind the upper border of the pancreas with the
splenic vein, to form the vena porta3.
The Splenic Vein commences by five or six large branches, which return the
blood from the substance of the spleen. These uniting form a single vessel,
which passes from left to right behind the upper border of the pancreas, and ter-
minates at its greater end by uniting at a right angle with the superior mesenteric
2zj. — Portal Vein and its Branches.
to form the vena portse. The splenic vein is of large size, and not tortuous like
the artery. It receives the vasa brevia from the left extremity of the stomach,
the left gastro-epiploic vein, pancreatic branches from the pancreas, the pan-
creatico-duodenal vein, and the inferior mesenteric vein.
The Gastric is a vein of small size, which accompanies the gastric artery from
left to right along the lesser curvature of the stomach, and terminates in the vena
portse.
PORTAL; CARDIAC. 423
The Portal Vein is formed by the junction of the superior mesenteric and
splenic veins, their union taking place in front of the vena cava, and behind
the upper border of the great end of the pancreas. Passing upwards through the
right border of the lesser omentum to the under surface of the liver, it enters the
transverse fissure, where it is somewhat enlarged, forming the sinus of the portal
vein, and divides into two branches, which accompany the ramifications of the
hepatic artery and hepatic duct throughout its substance. Of these two branches
the right is the larger but the shorter of the two. The portal vein is about four
inches in length, and, whilst contained in the lesser omentum, lies behind and
between the hepatic duct and artery, the former being to the right, the latter to
the left. These structures are accompanied by filaments of the hepatic plexus
and numerous lymphatics, surrounded by a quantity of loose areolar tissue, the
capsule of Glisson, and placed between the layers of the lesser omentum.
The vena portse receives the gastric and cystic veins; the latter vein sometimes
terminates in the right branch of the vena portae. Within the liver, the portal
vein receives the blood from the branches of the hepatic artery.
Cardiac Veins.
The veins which return the blood from the substance of the heart are, the
Great cardiac vein. Anterior cardiac veins.
Posterior cardiac vein. Venas Thebesii.
The Great Cardiac Vein is a vessel of considerable size, which commences at
the apex of the heart, and ascends along the anterior ventricular groove to the
base of the ventricles. It then curves to the left side, around the auriculo-
ventricular groove, between the left auricle and ventricle, to the back part of
the heart, and opens into the coronary sinus, its aperture being guarded by two
valves. It receives the posterior cardiac vein, and the left cardiac veins from
the left auricle and ventricle, one of which, ascending along the left margin of
the ventricle, is of large size. The branches joining it are provided with
valves.
The Posterior Cardiac Vein commences, by small branches, at the apex of the
heart, communicating with those of the pi-eceding. It ascends along the groove
between the ventricles, on the posterior surface of the heart, to its base, and
terminates in the coronary sinus, its orifice being guarded by a valve. It receives
the veins from the posterior surface of both ventricles.
The Anterior Cardiac Veins are three or four small branches, which collect
the blood from the anterior surface of the right ventricle. One of these, larger
than the rest, runs along the right border of the heart, the vein of Galen. They
open separately into the lower part of the right auricle.
The Vena Thebesii are numerous minute veins, which return the blood
directly from the muscular substance, without entering the venous current. They
open, by minute orifices, {foramina Thebesii), on the inner surface of the right
auricle.
The Coronary Sinus is that portion of the coi-onary vein which is situated in
the posterior part of the left auriculo-ventricular groove. It is about an inch in
length, presents a considerable dilatation, and is covered by the muscular fibres of
the left auricle. It receives the great cardiac vein, the posterior cardiac vein, and an
oblique vein from the back part of the left auricle, the remnant of the obliterated
left innominate trunk of the foetus, described by Mr. Marshall. The coronary
sinus terminates in the right auricle, between the inferior vena cava and the
auriculo-ventricular aperture, its orifice being guarded by a semilunar fold of the
lining membrane of the heart, the coronary valve. • All the branches joining this
vessel, excepting the oblique vein, above-mentioned, are provided with valves.
424 VEINS.
The Pulmonary Veins.
The Pulmonary Veins return the arterial blood from the lungs to the left
auricle of the heart. They are four in number, two for each lung. The pul-
monary differ from other veins in several respects. i. They carry arterial,
instead of venous, blood. 2. They are destitute of valves. 3. They are only
slightly larger than the arteries they accompany. 4. And they accompany those
vessels singly. They commence in a capijlary net-work, upon the parietes of the
bronchial cells, where they are continuous with the ramifications of the pulmo-
nary artery, and, uniting together, form a single trunk for each lobule. These
branches, successively uniting, form a single trunk for each lobe, three for the
right, and two for the left, lung. The vein of the middle lobe of the right lung
unites with that from the upper lobe, in most cases, forming two trunks on each
side, which open separately into the left auricle. Occasionally they remain sepa-
rate; there are then three veins on the right side. Not unfrequently, the two
left pulmonary veins terminate by a cdramon opening.
Within the lung, the branches of the pulmonary artery are in front, the veins
behind, and the bronchi between the two.
At the root of the lung, the veins are in front, the artery in the middle, and
the bronchus behind.
Within the pericardium, their anterior surface is invested by the serous layer
of this membrane, the right pulmonary veins pass behind the right auricle and
ascending aorta; the left pass in front of the thoracic aorta, with the left pul-
monary arteiy.
Of the Lymphatics.
THE Lympliatics have derived their name from the appearance of the fluid con-
tained in their interior (Jympha, water). They are also called absorbents,
from the property these vessels possess of absorbing foreign matters into the
system, and carrying them into the circulation.
The lymphatic system includes not only the lymphatic vessels and the glands
through which they pass, but also the lacteal, or chyliferous vessels. The
lacteals are the lymphatic vessels of the small intestine, and differ in no respect
from the lymphatics generally, excepting that they carry a milk-white fluid, the
chyle, during the process of digestion, and convey it into the blood through the
thoracic duct.
The lymphatics are exceedingly delicate vessels, the coats of which are so
transparent, that the fluid they contain is readily seen through them. They
retain a nearly uniform size, being interrupted at intervals by constrictions, which
give to them a knotted or beaded appearance, owing to the presence of valves in
their interior. They are found in nearly every texture and organ of the body,
with the exception of the substance of the brain and spinal cord, the eyeball,
cartilage, tendon, membranes of the ovum, the placenta, and umbilical cord.
Their existence in the substance of bone is doubtful.
The lymphatics are arranged into a superficial and deep set. The superficial
vessels, on the surface of the body, are placed immediately beneath the integu-
ment, accompanying the superficial veins ; they join the deep lymphatics in
certain situations by perforating the deep fascia. In the interior of the body,
they lie in the sub-mucous areolar tissue, throughout the whole length of the
gastro-pulmonary and genito-urinary tracts; or in the sub-serous areolar tissue,
beneath the serous membrane covering the various organs in the cranial, thoracic,
and abdominal cavities. In each of these situations these vessels arise in the
form of a dense plexiform net- work, consisting of several strata; the vessels com-
posing which, as well as the meshes between them, are much larger than the
capillary plexus. From these net- works small vessels emerge, which pass, either
to a neighbouring gland, or to join some larger lymphatic trunk. The deep
lymphatics, fewer in number, and larger than the superficial, accompany the deep
blood-vessels. Their mode of origin is not known ; it is, however, probable, that
it is similar to that of the superficial vessels. The lymphatics of any part or
organ exceed, in number, the veins; but in size, they are much smaller. Their
anastomoses also, especially of the large trunks, is more frequent, and is effected
by vessels equal in diameter to those which they connect, the continuous trunks
retaining the same diameter.
The lymphatic vessels, like arteries and veins, are composed of three coats,
internal, middle, and external.
The internal is an epithelial and elastic coat. It is thin, transparent, slightly
elastic, and ruptures sooner than the other coats. It is composed of a layer of
scaly epithelium, supported on one or more lamina? of longitudinal elastic
fibres.
The middle, or muscular coat, is thin, extensile, and elastic, consisting inter-
nally of a layer of longitudinal muscular fibres of the involuntary kind, inter-
mixed with some areolar tissue, external to which, in the larger lymphatics, is a
layer of circular fibres.
The external, or areolar-fibrous coat, is similar to that of the blood-vessels. It
is thin, but very extensile and elastic, composed of filaments of areolar tissue, inter-
mixed with some muscular fibres, longitudinally or obliquely disposed. It forms a
426 LYMPHATICS.
protective covering to the other coats, and serves to connect the vessel with the
neighbouring structures.
The lymphatics are supplied by nutrient vessels, which are distributed to their
outer and middle coats ; but no nerves have at present been traced into them.
The lymphatics are very generally provided with valves, which assist very
materially in effecting the circulation of the fluid they contain. They are formed
of a thin layer of fibrous tissue, coated on both surfaces with scaly epithelium.
Their form is semilunar; they are attached by their convex edge to the sides of the
vessel, the concave edge being free, and directed in the course of the contained
current. Most usually, two such valves, of equal size, are found placed opposite
one another; but occasionally exceptions occur, especially at or near the anasto-
moses of lymphatic vessels. Thus one valve may be of very rudimentary size,
the other increased in proportion. In other cases, the semilunar flaps have been
found directed transversely across the vessel, instead of obliquely, so as to impede the
circulation in both directions, but not to completely arrest it in either; or the
semilunar flaps, taking the same direction, have been united on one side, so that
they formed, by their union, a transverse septum, having a partial transverse slit;
and sometimes the flap was constituted of a circular fold, attached to the entire
circumference of the vessel, and having in its centre a circular or elliptical aper-
ture, the arrangements of the flaps being similar to those composing the ilio-caecal
valve.
The valves in the lymphatic vessels are placed at much shorter intervals than
in the veins. They are most numerous near the lymphatic glands, and they are
found more frequently in the lymphatics of the neck and upper extremity, than in
the lower. The wall of the lymphatics, immediately above the point of attachment
of each segment of a valve, is expanded into a ,-pouch or sinus, which gives to
these vessels, when distended, the knotted or beaded appearance which they pre-
sent. Valves are wanting in the vessels composing the plexiform net-work in
which the lymphatics originate.
There is no satisfactory evidence to prove that any natural communication exists
between the lymphatics of glandular organs and their ducts, or between the lym-
phatics and the capillary vessels.
The lymphatic or absorbent glands, named also conglobate glands, are small
solid glandular bodies, situated in the course of the lymphatic and lacteal vessels.
They are found in the neck and on the external parts of the head; in the upper
extremity, in the axilla and front of the elbow; in the lower extremity, in the
groin and popliteal space. In the abdomen, they are found in large numbers in
the mesentery, and along the side of the aorta, vena cava, and iliac vessels; and in
the thorax, in the anterior and posterior mediastina. They are somewhat flattened,
and of a round or oval form. In size, they vary from a hemp-seed to an almond,
and their colour, on section, is of a pinkish grey tint, excepting the bronchial glands,
which in the adult are mottled with black. The lymphatic and lacteal vessels pass
through these bodies in their passage to the thoracic and lymphatic ducts. A
lymphatic or lacteal, previous to entering a gland, divides into several small
branches, which are named inf event or afferent vessels (vasa inferentia or afferentia) ;
and those which emerge from it are called efferent vessels (vasa efferentia). In
structure they are composed of a superficial or cortical spongy substance about two
or three lines in thickness, containing numerous small cavities or loculi, filled with
a whitish pulpy matter; the afferent vessels pour their contents into these loculi,
which communicate by minute vessels with the lymphatic plexus composing the
centre or medullary portion of the gland, from which the efferent vessels emerge.
These plexuses of lymphatic vessels are intermixed with a capillary plexus, and
the whole enclosed in a thin fibro-areolar capsule.
Thoracic Duct.
The thoracic duct (fig. 227) conveys the great mass of the lymph and chyle
into the blood. It is the common trunk of all the lymphatic vessels of the body.
THORACIC DUCT.
427
tiympltatrc
Tnte-rcostuZ j
GZcCTi^'s r
excepting those of the right side of the head, neck, and thorax, and right upper
extremity, the right lung, right side of tlie heart, and the convex surface of
the liver. It varies from eighteen to twenty inches in length in the adult, and
extends from the second lum-
bar vertebra to the root of 227-— The Thoracic and Right Lymphatic Ducts.
the neck. It commences in
the abdomen by a triangular
dilatation, the receptaculum
chyli (reservoir or cistern of
Pecquet), which is situated
upon the fi-ont of the body of
the second lumbar vertebra,
to the right side and behind
the aorta, by the side of the
right crus of the Diaphragm.
It ascends into the thorax
through the aortic opening
in the Diaphragm, and is
placed in the postetrior medias-
tinum in front of the vertebral
column, lying between the
aorta and vena azygos. Op-
posite the fourth dorsal ver-
tebra it inclines towards the
left side and ascends behind
the arch of the aorta, on the
left side of the oesophagus,
and behind the first portion
of the left subclavian artery,
to the upper orifice of the
thorax. Opposite the upper
border of the seventh cervical
vertebra it curves down-
wards above the subclavian
artery, and in front of the
Scalenus muscle, so as to form
an arch; and terminates near
the angle of junction of the
left internal jugular and sub-
clavian veins. The thoracic
duct, at its commencement, is
about equal in size to the dia-
meter of a goose-quill, dimi-
nishes considerably in its
calibre in the middle of the
thorax, and is again dilated
just before its termination.
It is generally flexuous in its
course, and constricted at in-
tervals so as to present a
varicose appearance. The
thoracic duct not unfrequently
divides in the middle of its
course into two branches of unequal size which soon re-unite, or into several
branches which form a plexiform interlacement. It occasionally bifurcates, at
its upper part, into two branches, the left terminating in the usual manner,
the right opening into the left subclavian vein, in connection with the right
Luiiiicti- Gla.ncis
428 LYMPHATICS.
lymphatic duct. The thoracic duct has numerous valves throughout its whole
course, but they are more numerous in the upper than in the lower part; at its
termination it is provided with a pair of valves, the free borders of which are
turned towards the vein, so as to prevent the regurgitation of venous blood into
the duct.
Branches. The thoracic duct at its commencement receives four or five large
trunks from the abdominal lymphatic glands, and also the trunk of the lacteal
vessels. Within the thorax, it is joined by the lymphatic vessels from the left
half of the wall of the thoracic cavity; and the lymphatics from the sternal and
intercostal glands, those of the left lung, left side of the heart, trachea, and 03so-
phagus; and just before its termination, receives the lymphatics of the left side of
the head and neck, and left upper extremity.
The Right Lymphatic Duct is a short trunk, about an inch in length, and a
line or a line and a half in diameter, which receives the lymph from the right side
of the head and neck, the right upper extremity, and right side of the thorax;
and terminates at the angle of union of the right subclavian and right internal
jugular veins. Its orifice is guarded by two semilunar valves, which prevent the
entrance of blood from the veins.
Branches. In addition to those already mentioned, it receives the lymphatics of
the right lung and right side of the heart, and some from the convex surface of
the liver.
Lymphatics of the Head, Face, and Neck.
The Superficial Lymphatic Glands of the Head (fig. 228) are of small size, few
in number, and confined to its posterior region. They are the occipital, placed at the
back of the head along the attachment of the Occipito-frontalis; and the posterior
auricular, near the upper end of the Sterno-mastoid. These glands become con-
siderably enlarged in cutaneous affections and other diseases of the scalp. Li the
face, the superficial lymphatic glands are more numerous: they are the, parotid,
some of which are superficial and others deeply placed in its substance; the zygo-
matic, situated under the zygoma; the buccal, on the surface of the buccinator
muscle; and the submaxillary, the largest, beneath the body of the lower jaw.
The Superficial Lymphatics of the Head are divided into an anterior and a
posterior set, which follow the course of the temporal and occipital vessels. The
tempoi-al set accompany the temporal artery in front of the ear, to the parotid
lymphatic glands, from which they proceed to the lymphatic glands of the neck.
The occipital set follow the course of the occipital artery, descend to the occipital
and posterior auricular lymphatic glands, and from thence join the cervical glands.
The Superficial Lymphatics of the Face are more numerous than those of the
head. They commence over its entire surface, those from the frontal region accom-
panying the frontal vessels; they then pass obliquely across the face, accompanying
the facial vein, pass through the buccal glands on the surface of the Buccinator
muscle, and join the submaxillary lymphatic glands. These glands receive the
lymphatic vessels from the lips, and are often found enlarged in cases of malignant
disease of this part.
The Deep Lymphatics of the Face are derived from the pituitary mem-
brane of the nose, the mucous membrane of the mouth and pharynx, and the
contents of the temporal and orbital fosso3; they accompany the branches of the
internal maxillary artery, and terminate in the deep parotid and cervical lymphatic
glands.
The Deep Lymphatics of the Cranium consist of two sets, the menin-
geal and cerebral. The meningeal lymphatics accompany the meningeal vessels,
escape through foramina at the base of the skull, and join the deep cervical lym-
phatic glands. The cerebral lymphatics are described by Fohmann as being
situated between the arachnoid and pia mater, as well as in the choroid plexuses
of the lateral ventricles; they accompany the trunks of the carotid and vertebral
arteries, and probably pass through foramina at the base of the skull, to terminate
OF THE HEAD, FACE, AND NECK.
429
in the deep cervical glands. They have not at present been demonstrated in the
dura mater, or in the substance of the brain.
The Lymphatic Glands of the Neck are divided into two sets, superficial and
deep.
The superficial cervical glands are placed in the course of the external jugular
vein, between the Platysma and Sterno-mastoid. They are most numerous at the
root of the neck, in the triangular interval between the clavicle, the Sterno-mas-
toid, and the Trapezius, where they are continuous with the axillary glands. A
few small glands are also found on the front and sides of the larynx.
228. — The Superficial Lymphatics and Glands of the Head, Face, and Neck.
The deep cervical glands (fig. 229) are numerous and of large size; they form
an uninterrupted chain along the sheath of the carotid artery and internal jugular
vein, lying by the side of the pharynx, oesophagus, and trachea, and extending
from the base of the skull to the thorax, where they communicate with the lym-
phatic glands in this cavity.
The Superficial and Deep Cervical Lymphatics are a continuation of those
already described on the cranium and face. After traversing the glands in those
regions, they pass through the chain of glands which lie along the sheath of
the carotid vessels, being joined by the lymphatics from the pharynx, oesopha-
gus, larynx, trachea, and thyroid gland. At the lower part of the neck, after
receiving some lymphatics from the thorax, they unite into a single trunk, which
430 LYMPHATICS.
terminates on the left side, in the thoracic duct; on the right side, in the right
lymphatic duct.
229. — The Deep Lymphatics and Glands of the Neck and Thorax.
Lymphatics of the Upper Extremity.
The Lymphatic Glands of the upper extremity (fig. 230) may be subdivided into
two sets, superficial and deep.
The superficial lymphatic glands are few, and of small size. There are occa-
sionally two or three in front of the elbow, and one or two above the internal
condyle of the humerus, near the basilic vein.
The deep lymphatic glands are also few in number. In the fore- arm a few
small ones are occasionally found in the course of the radial and ulnar vessels;
and in the arm, there is a chain of small glands along the inner side of the brachial
artery.
The Axillary Glands are of large size, and usually ten or twelve in number.
A chain of these glands surrounds the axillary vessels imbedded in a quantity of
loose areolar tissue; they receive the lymphatic vessels from the arm: others are
dispersed in the areolar tissue of the axilla: the remainder are arranged in two
series, a small chain running along the lower border of the Pectoralis major, as
far as the mammary gland, receiving the lymphatics from the front of the chest
and mamma; and others are placed along the lower margin of the posterior wall
OF THE UPPER EXTREMITY.
431
of the axilla, which receive the lymphatics from the integument of the back.
Two or three subclavian lymphatic glands are placed immediately beneath the
clavicle; it is through these that the axillary and deep cervical glands communi-
cate with each other. One is figured by Mascagni near the umbilicus. In
malignant diseases, tumours or other affections implicating the upper part of the
back and shoulder, the front of the chest and mamma, the upper part of the front
and side of the abdomen, or the hand, fore-arm, and arm, these glands are usually
found enlarged.
230. — The Superficial Lymphatics and Glands of the Upper Extremity,
AxtJIctrtj Glce/ids.^
I
The Superficial Lymphatics of the upper extremity arise from the skin of the
- hand, and run along the sides of the fingers chiefly on the dorsal surface of the
hand; they then pass up the fore-arm, and subdivide into two sets, which take
the course of the subcutaneous veins. Those from the inner border of the hand
accompany the ulnar veins along the inner side of the fore-arm to the bend of
the elbow, where they join with some lymphatics from the outer side of the fore-
arm, follow the course of the basilic vein, communicate with the glands imme-
432
LYMPHATICS.
231. — The Superficial Lymphatics and
Glands of the Lower Extremity.
S umerfociofPi
diately above the elbow, and terminate
in the axillary glands, joining with the
deep lymphatics. The superficial lym-
phatics from the outer and back part of
the hand accompany the radial veins to
the bend of the elbow, being less nume-
rous than the preceding. Here the greater
number join the basilic group; the rest
ascend with the cephalic vein on the outer
side of the arm, some crossing obliquely
the upper part of the Biceps to terminate
in the axillary glands, whilst one or two
accompany the cephalic vein in the cel-
lular interval between the Pectoralis ma-
jor and Deltoid, and enter the subclavian
lymphatic glands.
The Deep Lymphatics of the upper
extremity accompany the deep blood-ves-
sels. In the fore-arm they consist of
three sets, corresponding with the radial,
ulnar, and interosseous arteries; they
pass through the glands occasionally
found in the course of these vessels, and
communicate at intervals with the super-
ficial lymphatics. In their ascent up-
wards, gome of them pass through the
glands which lie upon the brachial artery;
they then enter the axillary and subcla-
vian glands, and at the root of the neck
terminate, on the left side in the thoracic
duct, and on the right side in the right
lymphatic duct.
Lymphatics of the Lower Extre-
mity.
The Lymphatic Glands of the lower
extremity may be subdivided into two
sets, superficial and deep.
The superficial lymphatic glands
of the lower extremity are confined to
the inguinal region.
The superficial inguinal glands,
placed immediately beneath the integu-
ment, are of large size, and vary from
eight to ten in number. They are divi-
sible . into two groups; an upper, dis-
posed irregularly along Poupart's liga-
ment, receiving the lymphatic vessels
from the integument of the scrotum,
penis, parietes of the abdomen, peri-
nteum, and gluteal regions; and an
inferior group^ which surround the sa-
phenous opening in the fascia lata, a
few being sometimes continued along
the saphena vein to a variable extent.
These receive the superficial lymphatic
OF THE LOWER EXTREMITY. 433
vessels from the lower extremity. These glands frequently become enhirged in
diseases imjilicating the parts from which their efferent lymphatics originate.
Thus, in malignant or syphilitic affections of the prepuce and penis, the labia
majora in the female, in cancer scroti, in abscess in the pcrinajum, or in any other
disease affecting the integument and superficial structures in these parts, or the
sub-umbilical part of the abdomen or gluteal region, the upper chain of glands is
almost invariably enlarged, the lower chain being implicated in diseases affecting
the lower limb.
The Deep Lymphatic Glands are the anterior tibial, popliteal, deep inguinal,
gluteal, and ischiatic.
The Anterior Tibial Gland is not constant in its existence. It is generally
found by the side of the anterior tibial artery, upon the interosseous membrane at
the upper part of the leg. Occasionally two glands are found in this situation.
The Deep Popliteal Glands, four or five in number, are of small size; they
surround the popliteal vessels, imbedded in the cellular tissue and fat of the popli-
teal space.
The Deep Inguinal Glands are placed beneath the deep fascia around the
femoral artery and vein. They are of small size, and communicate with the
superficial inguinal glands through the saphenous opening.
The Gluteal and Ischiatic Glands are placed, the former above, the latter
below the Pyriformis muscle, resting on their corresponding vessels as they pass
out of the great sacro-sciatic foramen.
The Lymphatics of the lower extremity, like the veins, may be divided into
two sets, superficial and deep.
The Superficial Lymphatics are placed between the integument and superficial
fascia, and are divisible into two groups, an internal group, which follow the
course of the internal saphena vein, and an external group, which accompany the
external saphena.
The internal group, the largest, commence on the inner side and dorsum of the
foot; they pass, some in front and some behind the inner ankle, ascend the leg
with the internal saphenous vein, pass with it behind the inner condyle of the
femur, and accompany it to the groin, where they terminate in the group of
inguinal glands which surround the saphenous opening. Some of the efferent
vessels from these glands pierce the cribriform fascia and sheath of the femoral
vessels, and terminate in a lymphatic gland contained in the femoral canal, thus
establishing a communication between the lymphatics of the lower extremity and
those of the trunk; others pierce the fascia lata, and join the deep inguinal
glands.
The external group arise from the outer side of the foot, ascend in front of the
anterior region of the leg, and just below the knee cross the tibia from without
inwards, to join the lymphatics on the inner side of the thigh. Others commence
on the outer side of the foot, pass behind the outer malleolus, and accompany
the extei-nal saphenous vein along the back of the leg, where they enter the
popliteal glands.
The Deep Lymphatics of the lower extremity are few in number, and accom-
pany the deep blood-vessels. In the leg they consist of three sets, the anterior
tibial, peroneal, and posterior tibial, which accompany the corresponding vessels,
being two or three in number to each: they ascend with the blood-vessels, and
enter the lymphatic glands in the popliteal space: the efferent vessels from these
glands accomjDany the femoral vein, and join the deep inguinal glands; from these
the vessels pass beneath Poupart's ligament, and communicate with the chain of
glands surrounding the external iliac vessels.
The deep lymphatics of the gluteal and ischiatic regions follow the course of the
blood-vessels, and join the gluteal and ischiatic glands at the great sacro-sciatic
foramen.
434
LYMPHATICS
Lymphatics of the Pelvis and Abdomen.
The Deep Lymphatic Glands in the Pelvis are the external iliac, the internal
iliac, and the sacral. Those of the abdomen are the lumbar glands.
The External Iliac Glands form an uninterrupted chain around the external
232. — The Deep Lymphatic Vessels and Glands of the Abdomen and Pelvis.
Saeral Glai/cfs
J[nfer7?aT
\ Tlinc ainni/s
Exter-nal
Iliac Glands
Desj,
InquiHol
iliac vessels, three being placed around the commencement of the vessel just
behind the crural arch. They communicate by one extremity with the femoral
lymphatics, and by the other with the lumbar glands.
The Internal Iliac Glands surround the internal iliac vessels; they receive the
lymphatics corresponding to the branches of the internal iliac artery, and commu-
nicate with the lumbar glands.
OF THE PELVIS AND ABDOMEN. 435
The Sacral Glands occupy the sides of the anterior surface of the sacrum, some
being situated in the folds of the meso-rectum. These and the internal iliac glands
become greatly enlarged in malignant disease of the bladder, rectum, or uterus.
The Lumbar Glands are very numerous; they are situated on the front of
the lumbar vertebrae, surrounding the common iliac vessels, the aorta, and vena
cava; they receive the lymphatic vessels from the lower extremities and pelvis, as
well as from the testes and some of the abdominal viscera: the efferent vessels
from these glands unite into a few large trunks, which, with the lacteals, form the
commencement of the thoracic duct. In some cases of malignant disease, these
glands become enormously enlarged, completely surrounding the aorta and vena
cava, and occasionally greatly contracting the calibre of these vessels. Li all
cases of malignant disease of the testis, and in malignant disease of the lower
limb, before any operation is attempted, careful examination of the abdomen
should be made in order to ascertain if any enlargement exists, and if any should
be detected, all operative measures are fruitless.
The Lymphatics of the Pelvis and Abdomen may be divided into two sets,
superficial and deep.
The Superficial Lymphatics of the walls of the abdomen and pelvis follow the
course of the superficial blood-vessels. Those derived from the integument of
the lower part of the abdomen below the umbilicus, follow the course of the
superficial epigastric vessels, and converge to the superior group of the superficial
inguinal glands, the deep set accompany the deep epigastric vessels, and com-
municate with the external iliac glands. The superficial lymphatics from the
sides and lumbar part of the abdominal wall wind round the crest of the ilium,
accompanying the superficial circumfiex iliac vessels, to join the superior group of
the superficial inguinal glands; the greater number, however, accompany the ilio-
lumbar and lumbar vessels backwards to join the lumbar glands.
The Superficial T^ymphatics of the Gluteal Region turn horizontally round the
Outer side of the nates, and join the superficial inguinal glands.
The Superficial Lymphatics of the Scrotum and Perinceum follow the course of
the external pudic vessels, and terminate in the superficial inguinal glands.
The Superficial Lymphatics of the Penis occupy the sides and dorsum of the
organ, the latter receiving the lymphatics from the skin covering the gians penis;
they all converge to the superior group of the superficial inguinal glands. The
deep lymphatic vessels of the penis follow the course of the internal pudic vessels,
and join the internal iliac glands.
In the female, the lymphatic vessels of the mucous membrane of the labia,
nymphae, and clitoris, terminate in the superior group of the inguinal lymphatic
glands.
The Deep Lymphatics of the Pelvis and Abdomen take the course of the prin-
cipal blood-vessels. Those of the parietes of the pelvis, which accorajDany the
gluteal, ischiatic, and obturator vessels, follow the course of the internal iliac
artery, and ultimately join the lumbar lymphatics.
The efferent vessels from the inguinal glands enter the pelvis beneath Poupart's
ligament, where they lie in close relation with the femoral vein; they then pass
through the chain of glands surrounding the external iliac vessels, and finally
terminate in the lumbar glands. They receive the deep epigastric, circumflex
ilii, and ilio-lumbar lymphatics.
The Lymphatics of the Bladder arise from the entire surface of the organ ; the
greater number run beneath the peritoneum on its posterior surface, and, after
passing through the lymphatic glands in this situation, join with those from the
prostate and vesiculje seminales, and enter the internal iliac glands.
The Lymphatics of the Rectum are of lai'ge size; after passing through some
small glands that lie upon its outer wall and in the meso-rectum, they pass to the
sacral or lumbar glands.
The L.ymphatics of the Uterus consist of two sets, superficial and deep; the
former being placed beneath the peritoneum, the latter in the substance of the
F F 2
436 LYMPHATICS
organ. The lymphatics of the cervix uteri, together with those from the
vagina, enter the internal iliac and sacral glands: those from the body and fundus
of the uterus pass outwards in the broad ligaments, and being joined by the lym-
phatics from the ovaries, broad ligaments, and Fallopian tubes, ascend with the
ovarian vessels to open into the lumbar glands. In the unimpregnated uterus
they are small, but during gestation they become very greatly enlarged.
The Lymphatics of the Testicle consist of two sets, superjficial and deep;
the former commence on the surface of the tunica vaginalis, the latter in the
epididymis and body of the gland. They form several large trunks, which
ascend with the spermatic cord, and accompanying the spermatic vessels into the
abdomen, open into the lumbar glands; hence the enlargement of these glands in
malignant disease of this organ.
The Lymphatics of the Kidney arise on the surface, and also in the interior of
the organ; they unite together at the hilus, and after receiving the lymphatic
vessels from the ureters and supra-renal capsules, open into the lumbar glands.
The Lymphatics of the Liver are divisible into two sets, superficial and deep.
The foi'mer arise in the sub-peritoneal areolar tissue over the entire surface of the
organ. Those on the convex surface may be divided into four groups: I. Those
which pass from behind forwards, consisting of three or four trunks, which
ascend in the longitudinal ligament, and unite to form a single trunk, which passes
up bet\v^een the fibres of the Diaphragm, behind the ensiform cartilage, to enter
the anterior mediastinal glands, and finally ascend to the root of the neck, to
terminate in the right lymphatic duct. 2. Another group, which also incline
from behind forwards, are reflected over the anterior margin of the liver to its
concave surface, and from thence pass along the longitudinal fissure to the glands
in the gastro-hepatic omentum. 3. A third group incline outwards to the right
lateral ligament, and uniting into one or two large trunks, pierce the Diaphragm,
and run along its upper surface to enter the anterior mediastinal glands; or, in-
stead of entering the thorax, turn inv\^ards across the crus of the Diaphragm,
and open into the commencement of the thoracic duct. 4. The fourth group in-
cline outwards from the surface of the left lobe of the liver to the left lateral
ligament, pierce the Diaphragm, and passing forwards, terminate in the glands in
the anterior mediastinum.
The Superficial Lymphatics on the under surface of the Liver may be divided
into three sets: i. Those on the right side of the gall-bladder enter the lumbar
glands. 2. Those surrounding the gall-bladder form a remarkable plexus, which
accompanies the hepatic vessels, and open into the glands in the gastro-hepatic
omentum. 3. Those on the left of the gall-bladder pass to the oesophageal
glands, and to those placed along the lesser curvature of the stomach.
The Deep Lymphatics accompany the branches of the portal vein and the
hepatic artery and duct through the substance of the gland; passing out at the
transverse fissure, they enter the lymphatic glands along the lesser curvature of
the stomach and behind the pancreas, or join with one of the lacteal vessels pre-
vious to its termination in the thoracic duct.
The Lymphatic Glands of the Stomach are of small size; they are placed
along the lesser and greater curvatures, some within the gastro-splenic omentum,
whilst others surround its cardiac and pyloric orifices.
The Lymphatics of the Stomach consist of two sets, superficial and deep; the
former originating in the subserous, and the latter in the submucous coats. They
follow the course of the blood-vessels, and may consequently be arranged into
three groups. The^r*; group accompany the coronary vessels along the lesser
curvature, receiving branches from both surfaces of the organ, and pass to the
glands ai'ound the pylorus. The second groxip pass from the great end of the
stomach, accompany the vasa brevia, and enter the splenic lymphatic glands.
The third group run along the greater curvature with the right gastro-epiploic
vessels, and terminate at the root of the mesentery in one of the principal lacteal
vessels.
OF THE THORAX.
437
The Lymphatic Glands of the Spleen occupy the hllus. Its lymphatic vessels
consist of two sets, superficial and deep; the former being placed beneath its peri-
toneal covering, the latter in the substance of the organ: tliey accomj^any the
blood-vessels, passing through a series of small glands, and after receiviiig those
derived from the pancreas, ultimately pass into the thoracic duct.
The Lymphatic System of the Intestines.
The Lymphatic Glands of the Small Intestines are placed between the layers
of the mesentery, occupying the meshes formed by the suj)erior mesenteric vessels,
and hence called mesenteric glands. They vary in number from a hundred and
thirty to. about a hundred and fifty, and are about the size of an almond. These
glands are most numerous, and largest, superiorly near the duodenum, and infe-
riorly opposite the termination of the ileum in the colon. This latter group
becomes greatly enlarged and infiltrated with deposit in cases of fever accom-
panied with ulceration of the intestines.
The Lymphatic Glands of the Large Intestine are much less numerous than
the mesenteric glands; they are situated along the vascular arches formed by the
arteries previous to their distribution, and even sometimes upon the intestine itself.
They are fewest in number along the transverse colon, where they form an unin-
terrupted chain with the mesenteric glands.
The Lymphatics of the Small Intestine are called lacteals, from the
milk-white fluid they usually contain: they consist of two sets, superficial and
deep; the former lie beneath the peritoneal coat, taking a longitudinal course
along the outer side of the intestine; the latter occupy the submucous tissue, and
course transversely round the intestine, accompanied by the branches of the
mesenteric vessels: they pass between the layers of the mesentery, enter the
mesenteric glands, and fiivally unite to form two or three large trunks, which
terminate in the thoracic duct.
The Lymphatics of the Great Intestine consist of two sets: those of the coecum,
ascending and transverse colon, which, after passing through their proper glands,
enter the mesenteric glands; and those of the descending colon and rectum, which
pass to the lumbar glands.
The Lymphatics of the Thokax.
The Deep Lymphatic Glands of the Thorax are the intercostal, intei'nal mam-
maiy, anterior mediastinal, and posterior mediastinal.
The Intercostal Glands are small, ii-regular in number, and situated on each
side of the spine, near the costo-vertebral articulations, some being placed be-
tween the two planes of intercostal muscles.
The Internal Mammary Glands are placed at the anterior extremity of each
intercostal space, by the side of the internal mammary vessels.
The Anterior Mediastinal Glands are placed in the loose areolar tissue of the
anterior mediastinum, some lying upon the Diaphragm in front of the pericardium,
and others around the great vessels at the base of the heart.
The Posterior Mediastinal Glands are situated in the areolar tissue in the
posterior mediastinum, forming a continuous chain by the side of the aorta and
oesophagus; they communicate on each side with the intercostal, below with the
lumbar glands, and above with the deep cervical.
The Superficial Lymphatics of the front of the Thorax run across the great
Pectoral muscle, and those on the back part of this cavity lie upon the Trapezius
and Latissimus dorsi; they all converge to the axillary glands. The lymphatics
.from the mamma run along the lower border of the Pectoralis major, through a
chain of small lymphatic glands, and communicate with the axillary glands.
The Deep Lymphatics of the Thorax are the intercostal, internal mammary,
and diaphragmatic.
The Intercostal Lijmphatics follow the course of the intercostal vessels, recaiving
lymphatics from the Intercostal muscles and pleura; they pass backwards to the
438 LYMPHATICS.
spine, and unite with lymphatics from the back part of the thorax and spinal
canal. After traversing the intercostal glands, they incline down the spine, and
terminate in the thoracic duct.
The Internal Mammary Lymphatics follow the course of the internal mam-
mary vessels: they commence in the muscles of the abdomen above the umbilicus,
communicating with the epigastric lymphatics, ascend between the fibres of the
Diaphragm at its attachment to the ensiform appendix, and in their course behind
the costal cartilages are joined by the intercostal lymphatics, terminating on the
right side in the right lymphatic duct, on the left side in the thoracic duct.
The Lymphatics of the Diaphragm follow the course of their corresponding
vessels, and terminate, some in front in the inferior mediastinal and internal mam-
mary glands, some behind in the intercostal and hepatic lymphatics.
The Bronchial Glands are situated around the bifurcation of the trachea and
roots of the lungs. They are ten or twelve in number, the largest being placed
opposite the bifurcation of the trachea, the smallest around the bronchi and their
primary divisions for some little distance within the substance of the lungs. In
infancy, they present the same appearance as lymphatic glands in other situations,
in the adult they assume a brownish tinge, and in old age a deep black colour.
Occasionally they become sufficiently enlarged to compress and narrow the canal
of the bronchi; and they are often the seat of tubercle or deposits of phosphate
of lime.
The Lymphatics of the Lung consist of two sets, superficial and deep: the
former are placed beneath the pleura, forming a minute plexus, which covers the
outer surface of the lung; the latter accompany the blood-vessels, and run along
the bronchi: they both terminate at the root of the lungs in the bronchial glands.
The efferent vessels from these glands, two or .three in number, ascend upon the
trachea to the root of the neck, traverse the tracheal and oesophageal glands, and
terminate on the left side in the thoracic duct, on the right side in the right
lymphatic duct.
The Cardiac Lymphatics consist of two sets, superficial and deep; the former
arise in the subserous areolar tissue of the surface, and the latter beneath the
internal lining membrane of the heart. They follow the course of the coronary
vessels ; those of the right side unite into a trunk at the root of the aorta, which,
ascending across the arch of that vessel, passes backwards to the trachea, upon
which it ascends, to terminate at the root of the neck in the right lymphatic
duct. Those of the left side unite into a single vessel at the base of the organ,
which passing along the pulmonary artery, and traversing some glands at the root
of the aorta, ascends on the trachea to terminate in the thoracic duct.
The Thymic Lymphatics arise from the spinal surface of the thymus gland,
and terminate on each side in the internal jugular veins.
The Thyroid Lymphatics arise from either lateral lobe of this organ; they
converge to form a short trunk, which terminates, on the right side in the right
lymphatic duct, on the left side in the thoracic duct.
The Lymphatics of the (Esophagus form a plexus around that tube, traverse
the glands in the posterior mediastinum, and, after communicating with the pul-
monary lymphatic vessels near the root of the lungs, terminate in the thoracic
duct.
T
NervoQS System.
HE Nervous System consists of a series of connected central organs, called,
J- collectively, the cerebro-spinal centre or axis, of the ganglia, and of the
nerves.
The Cerebro- Spinal Axis consists of two portions, the brain or encephalon, which
is contained within the cranium, and the spinal cord, continuous with the brain,
which is enclosed in the spinal canal. The cerebro-spinal centre consists of two
lateral symmetrical halves, which correspond in their structure in every respect;
they are partially separated by longitudinal fissures, and connected together by
broad transverse bands of nervous substance, called commissures.
The cerebi'o- spinal axis consists of two substances, which differ from each
other in density and colour; they are called the grey cineritious or cortical sub-
stance, and the white or medullary.
The grey or cortical substance is disposed in the form of a thin layer upon the
outer surface of the convolutions of the cerebrum and laminas of the cerebellum ;
it is not confined, however, to the external surface, for it exists in the interior of
the spinal cord throughout its entire length, and from this part may be traced up
through the medulla oblongata, pons Varolii, and crura cerebri, to the central
parts of the hemispheres, the optic thalami, and corpora striata. It also forms at
the base of the brain, the lamina cinerea, the tuber cinereum, and the grey matter
in the anterior and posterior perforated spaces. The grey matter may be traced
from the anterior perforated space into the olfactory nerve as far as the bulb, and
from the posterior space as forming part of the infundibulum and pituitary body.
The grey matter in this situation is continued upon the sides of the thalami,
forms the soft commissure, surrounds the anterior pillars of the fornix, enters
below into the substance of the corpus albicans; and, above, forms part of the
lateral walls of the septum lucidum. It is also found in the centre of each of the
corpora quadrigemina, in the pineal gland, and corpora geniculata. It forms also
the corpus dentatum in the centre of each lateral lobe of the cerebellum.
The white or medullary portion of the cerebro-spinal axis consists of fibres,
which are arranged chiefly in a longitudinal direction, or interlace at various
angles with transverse fibres ; they may be arranged into three classes, ascending,
transverse, and longitudinal. The ascending fibres pass up from the medulla
oblongata, increase in number as they ascend through the pons, the optic thalami,
and striated bodies, and then diverge to every part of the surface of the hemi-
spheres. They were called by Grail the diverging fibres. The transverse or com-
missural fibres commence at the surface of the hemispheres, and proceed inwards
towards the centre, connecting the two hemispheres together; these were named
by Gall the converging fibres. The longitudinal fibres, also commissural, connect
together different parts of the same hemisphere, being confined to the same side
of the middle line.
Chemical Composition. The following analysis by Lassaigne represents the
relative proportion of the different constituents composing the grey and white
matter of the brain.
Grey. White.
Water 85'2 . 73*0
Albuminous matter 7*5 . 9*9
Colourless fat I'O . I3'9
Red fat ... 37 • ^'9
Osmazome and lactates .... 1*4 . I'O
Phosphates i'2 . i'3
lOO'O . 100*0
440 NERVOUS SYSTEM.
It appears from this analysis, that the cerebral substance consists of albumen,
dissolved in water, combined with fatty matters and salts. The fatty matters,
according to Fremy, consist of cerebric acid, which is most abundant, cholesterin,
oleophosphoric acid, and olein, margarin, and traces of their acids. The same
analyst states, that the fat contained in the brain is confined almost exclusively
to the white substance, and that its colour becomes lost when the fatty matters
are removed. According to Vauquelin, the cord contains a larger projDortion of
fat than the brain; and according to L'Heritier, the nerves contain more albumen
and more soft fat than the brain.
The Ganglia may be regarded as separate and independent nervous centres, of
smaller size and less complex structure than the brain, connected with each other,
with the cerebro-spinal axis, and with the nerves in various situations. They are
found on the posterior root of each of the spinal nerves; on the posterior or
sensory root of the fifth cranial nerve; on the seventh nerve; on the two sensory
divisions of the eighth pair (the glosso-pharyngeal and pneumogastric); in a
connected series along each side of the vertebral column, forming the trunk of the
sympathetic; on the branches of this nerve in the head, neck, thorax, and abdo-
men; or at the point of junction of branches of this nerve with the cerebro-
spinal nerves. On section, they are seen to consist of a reddish grey substance,
traversed by numerous white nerve-fibres: they vary considerably in form and
size; the largest are those found in the cavity of the abdomen; the smallest, the
microscopic ganglia, which exist in considerable numbers upon the nerves distri-
buted to the different viscera. The ganglia are invested by a smooth and firm
closely-adhering membranous envelope, consisting of dense areolar tissue; this
sheath is continuous with the neurilemna of the nerves, and sends numerous pro-
cesses into the interior of the ganglia, which support the blood-vessels supplying
its substance.
The Nerves are round or flattened white cords, communicating on the one hand
with the cerebro-spinal centre or the ganglia, and by the other distributed to the
various textures of the body, forming the medium of communication between the
two. One class of nerve-fibres, the afferent or centripetal, serve to convey im-
pressions to the brain, the great centre of sensation and volition, where they are
rendered cognizable to the mind; whilst another class of nerve-fibres, the efferent
or centrifugal, convey the stimulus of volition to the organs of motion. The
brain and spinal cord are also capable of receiving impressions by means of
the afferent nerve-fibres, which results in a motorial stimulus being propagated
along the efferent nerves, quite independent of the efforts of volition, and without
even consciousness. The movements of this kind are called reflex or excito-motory.
The nerves are subdivided into two great classes, the cerebro-spinal, which
proceed from the cerebro-spinal axis, and the sympathetic or ganglionic nerves,
which proceed from the sympathetic ganglia; the cerebro-spinal are the nerves of
animal life, being distributed to the organs of the senses, the skin, and to the
active organs of locomotion, the muscles. The sympathetic or ganglionic nerves
are distributed chiefiy to the viscera and blood-vessels, and are termed the nerves
of organic life.
The cerebro-spinal nerves consist of numerous nerve-fibres, collected together
and enclosed in a membranous sheath. A small. bundle of primitive fibres enclosed
in a tubular sheath is called a funiculus: if the nerve is of small size, it may
consist only of a single funiculus, but if large, the funiculi are collected together
into larger bundles or fasciculi; and one or more fasciculi bound together in a
common membranous investment, termed the sheath, constitutes a nerve. In
structure, the common sheath investing the whole nerve, as well as the septa
given off" from it, which separates the fasciculi, consists of areolar tissue, com-
posed of the white and yellow elastic fibres, the latter existing in greatest abun-
dance. The tubular sheath of the funiculi, or neurilemma, consists of a fine
smooth transparent membrane, which may be easily separated, in the form of a
tube, froHj the fibres it encloses; in structure, it is, for the most part, a simple
GENERAL ANATOMY. 441
and homogeneous transparent film, occasionally composed of numerous minute
reticular fibres.
The nerve-fibres, as far as is at present known, do not coalesce, but pursue an
uninterrujited course from the centre to the periphery. In dissecting a nerve,
however, into its component funiculi, it may be seen that they do not pursue a
perfectly insulated course, but occasionally join at a very acute angle with other
funiculi proceeding in the same direction; from these again branches are given off,
which join again in like manner with other funiculi. It must be remembered,
however, that in these communications the nerve-fibres do not coalesce, but merely
pass into the sheath of the adjacent nerve, become intei-mixed with the nerve-
fibres, and again pass on to become blended with the nerve-fibres in some adjoining
fasciculus.
The cerebro- spinal nerves consist almost exclusively of the tubular nerve-fibres,
the gelatinous fibres existing in very small proportion.
The blood-vessels supplying a nerve terminate in a minute capillary plexus, the
vessels composing which run, for the most part, parallel with the funiculi; they
are connected together by short transverse vessels, forming narrow oblong meshes,
similar to the capillary system of muscle.
Nerves in their course subdivide into branches, and these frequently commu-
nicate with branches of a neighbouring nerve. In the subdivision of a nerve, the
filaments of which it is composed are continued from the trunk into the branches,
and at their junction with the branches of neighbouring nerves, the filaments pass
to become intermixed with those of the other nerve in their further progress; in
no instance, however, do the separate nerve-fibres either subdivide or inosculate.
The communications which take place between two or more nerves form what
is called a plexus. Sometimes a plexus is formed by the primary branches of the
trunks of the nerves, as the cervical, brachial, lumbar, and sacral plexuses, and
occasionally by the terminal fasciculi, as in the plexuses formed at the periphery
of the body. In the formation of a plexus, the component nerves divide, then
join, and again subdivide in such a complex manner that the individual fasciculi
become interlaced most intricately; so that each branch leaving a plexus may con-
tain filaments from each of the primary nervous trunks which form it. In the
formation also of the smaller plexuses at the periphery of the body, there is a free
interchange of the fasciculi and primitive fibrils. In each case, however, the
individual filaments remain separate and distinct, neither subdividing nor inos-
culating.
Some nerve-fibres have no peripheral termination. Grerber has shewn, that
nerve-fibres occasionally form loops by their junction with a neighbouring fibre in
the same fasciculus, and retui'n to the cerebro-spinal centre without having any
peripheral termination. These he considers to be sentient nerves, appropriated
exclusively to the nerve itself, the nervi nervorum, upon which the sensibility of
the nerve depends, and quite exclusive of the sensation produced by an impression
made at the peripheral end of the nerve. These fibres bear some analogy to those
met with in the posterior part of the optic commissure, where a set of fibres pass
from one optic tract across the commissure to the opposite tract, having no com-
munication with the optic nerve; also in the communications formed between the
cervical nerves and spinal accessory and descendens noni, the nerve-fibres form
an arch connected by each extremity with the cerebro-spinal centre, and have
no peripheral termination.
Again, some nerve-fibres would appear to have no central connection with the
cerebro-spinal centre, as those forming the most anterior part of the optic com-
-missure. These inter-retinal fibres, as they are called, commence in the retina,
pass along the optic nerve, and across the commissure to the optic nerve and
retina of the opposite side.
The point of connection of a nerve with the brain or spinal cord is called, for
convenience of description, its origin or root. If the fasciculi of which the nerve
is composed should all arise at or near one point, or along one tract, the root is
442 NERVOUS SYSTEM.
called single. If, on the contrary, the fasciculi divide into two separate bundles,
which are connected at two different points with any part of the cerebro-spinal
centre, such nerve is said to have a double origin, or to arise by two roots, each
of which may have a separate function, as in the spinal nerves. The point where
the separate fasciculi of a nerve are connected to the surface of the cerebro-spinal
centre is called the apparent origin of a nerve; the term 'reader deep origin
being given to that part of the centre from which a nerve actually springs.
The nerve-fibres at their periphery terminate in a varied manner. Occasionally
the elementary fibres are disposed in terminal loops or plexuses, which, for a con-
siderable period, was supposed to be their usual mode of termination, but later
investigations have shewn that such is not the case. Nerve-fibres most commonly
terminate by blunted and slightly-swollen ends, such as is observed in those which
enter into the Paccinian bodies, or they may become gradually lost to view in
the tissue in which they are distributed, becoming diminished in size, and their
tubular sheath and white substance being wanting. Occasionally the elementary
nerve-fibres, as in the nerves of special sense, may be brought into connection at
their periphery with cells similar to those met with in the grey matter of the
brain and ganglia.
The Sympathetic System consists of numerous parts, which may be arranged
as follows. I. A connected series of ganglia placed along both sides of the spinal
column, from the cranium above to the coccyx below. 2. Branches of commu-
nication passing between the ganglia. 3. Branches of connection between the
ganglia and the cranial and spinal nerves. 4. Primary branches of distribution,
remarkable for their plexiform communications on the vessels, glands, and neigh-
bouring viscera to which they are distributed, or for passing to other larger ganglia,
situated in each of the great cavities of the body,^nd usually placed on the roots of
origin of the larger blood-vessels. 5. Plexuses of nerves proceeding from these
secondary ganglia, accompanying the blood-vessels, and receiving branches from
the spinal or cerebral nerves. The sympathetic nerves consist of tubular and
gelatinous fibres, intermixed with a varying proportion of filamentous areolar
tissue, and enclosed in a sheath formed of fibro-areolar tissue. The tubular fibres
are, for the most part, smaller than those composing the cerebro-spinal nerves;
their double contour is less distinct, and, according to Remak, they present nuclei
similar to those found in the gelatinous nerve-fibres. Those branches of the
sympathetic which present a well-marked grey colour, are composed more espe-
cially of gelatinous nerve-fibres, intermixed with few tubular fibres; whilst those
of a white colour contain more of the tubular fibres, and few gelatinous. Occa-
sionally the grey and white cords run together in a single nerve, without any
intermixture, as in the branches of communication between the sympathetic ganglia
and the spinal nerves, or in the communicating cords between the ganglia.
The Cerebro- Spinal Centre consists of two parts, the spinal cord and the ence-
phalon: the latter may be subdivided into the cerebrum or brain proper, the cere-
bellum or little brain, the tuber annulare or pons Varolii, and the medulla
oblongata.
The Spinal Cord and its Membranes.
Dissection. To dissect the cord and its membrane's, it will be necessary to lay open the
whole length of the spinal canal. For this purpose, the muscles must be separated from
the vertebral grooves, so as to expose the spinous processes and laminse of the vertebrae ;
and the latter must be sawn through on each side, close to the roots of the transverse
processes, from the third or fourth cervical vertebra, above, to the sacrum below. The
vertebral arches having been displaced, by means of a chisel, and the separate fragments
removed, the dura mater will be exposed, covered by a plexus of veins and a quantity of
loose areolar tissue, often infiltrated with serous fiuid. The arches of the upper vertebrae
are best divided by means of a strong pair of forceps.
Membranes of the Cord.
The membranes which envelope the spinal cord are three in number. The
MEMBRANES OF THE CORD.
443
233.
-The Spinal Cord and its
Membranes.
most external is the dura mater, a strong fibrous membrane, which forms a loose
sheath around the cord. The most internal is the pia mater, a cellulo-vascular
membrane, which closely invests the entire surface of the cord. Between
the two, is the arachnoid membrane, an intermediate serous sac, which
envelopes the cord, and is then reflected on the inner surface of the dura
mater.
The Dura Mater of the cord, continuous with that which invests the brain,
is a loose sheath which surrounds it, being sepa-
rated from the bony walls of the spinal canal by a
quantity of loose areolar adipose tissue, and a
plexus of veins. It is attached, above, to the cir-
cumference of the foramen magnum, and extends,
below, as far as the top of the sacrum; but, be-
yond this point, it is impervious, being continued,
in the form of a slender cord, to the back of the
coccyx, where it blends with the periosteum. This
sheath is much larger than is necessary for its con-
tents, and its size is greater in the cervical and
lumbar regions, than in the dorsal. Its inner sur-
face is smooth, being lined by the arachnoid
membrane; and on each side may be seen the
double openings which transmit the two roots of
the corresponding spinal nerve, the fibrous layer of
the dura mater being continued in the form of a
tubular prolongation on them as they issue from
these apertures, and becoming lost upon them.
These prolongations of the dura mater are short
in the upper part of the spine, but become gradu-
ally longer below, forming a number of tubes of
fibrous membrane, which enclose the sacral nerves,
and are contained in the spinal canal.
The chief peculiarities of the dura mater of the
cord, as compared with that investing the brain,
are the following:
The dura mater of the cord is not adherent to the bones of the spinal canal,
which have an independent periosteum.
It does not send partitions into the fissures of the cord, as in the brain.
Its fibrous laminge do not separate, to form venous sinuses, as in the brain.
Structure. The dura mater consists
234. — Transverse Section of the Spinal Cord
and its Membranes.
of white fibrous tissue, arranged in
bands, which intersect one another. It
is sparingly supplied with vessels, as
compared with the dura mater of the
brain; and no nerves have as yet been
traced into it.
The Arachnoid is exposed by slitting
up the dura mater, and reflecting this
membrane on either side (fig. 233). It is
a thin, delicate, serous membrane, which
invests the outer surface of the cord, and
is then reflected upon the inner surface
of the dura mater, to which it is intimately adherent. That portion which
surrounds the cord, is called the visceral layer of the arachnoid ; and that which
lines the inner surface of the dura mater, the parietal layer ; the interval between
the two, is called the cavity of the arachnoid. The visceral layer forms a loose
^lieath around the cord, so as to leave a considerable interval between the two,
which is called the sub-arachnoidean space. This space is largest at the lower
444 NERVOUS SYSTEM.
part of the spinal canal, and encloses the mass of nerves which form the cauda
equina. It contains an abundant serous secretion, the cerebro-spinal fluid, and
usually communicates with the general ventricular cavity of the brain, by means
of an opening in the fibrous layer of the inferior boundary of the fourth ven-
tricle. This secretion is sufficient in amount to expand the arachnoid membrane,
so as to completely fill up the whole of the space included in the dura mater.
The sub-arachnoidean space is crossed, at the back part of the cord, by numerous
fibrous bands, which stretch from the arachnoid to the pia mater, especially in the
cervical region, and is partially sub-divided by a longitudinal membranous parti-
tion, which serves to connect the arachnoid with the pia mater, opposite the
posterior median fissure. This partition is incomplete, and cribriform in struc-
ture, consisting of bundles of white fibrous tissue, interlacing with each other.
The visceral layer of the arachnoid surrounds the spinal nerves where they
arise from the cord, and encloses them in a tubular sheath as far as their
point of exit from the dura mater, where it becomes continuous with the parietal
layer.
The arachnoid is not very vascular. No nerves have as yet been traced into
this membrane.
The Pia Mater of the cord is exposed on the removal of the arachnoid (fig. 233).
It is less vascular in structure than the pia mater of the brain, with which it is
continuous, being thicker, more dense in structure, and composed of fibrous tissue,
arranged in longitudinal bundles. It covers the entire surface of the cord, to
which it is very intimately adherent, forming its neurilemma, and sends a process
downwards into its anterior fissure, and another, extremely delicate, into the
posterior fissure. It also forms a sheath for each of the filaments of the spinal
nerves, and invests the nerves themselves. A longitudinal fibrous band extends
along the middle line on its anterior surface, called by Haller, the linea splendens;
and a somewhat similar band, the ligamentum denticulatum, is situated on each
side. At the point where the cord terminates, the pia mater becomes contracted,
and is continued down as a long, slender filament, which descends through
the centre of the mass of nerves forming the cauda equina, and is blended with
the impervious sheath of dura mater (before mentioned), on a level with the top
of the sacral canal. It assists in maintaining the cord in its position during the
movements of the trunk, and is, from this circumstance, called the central liga-
ment of the spinal cord. It contains a little nervous substance, which may be
traced for some distance into its upper part, and is accompanied by a small artery
and vein.
Structure. The pia mater of the cord, though less vascular than that which
invests the brain, contains a network of delicate vessels in its substance. It is
also supplied with nerves, which, according to Purkinje, are derived from the
sympathetic; but Remak states that they are chiefly supplied from the posterior
roots of the spinal nerves. At the upper part of the cord, it presents a greyish,
mottled tint, which is owing to yellowish or brown pigment cells being scattered
within its tissue.
The Ligamentum Denticulatum (fig, 233) is a narrow, fibrous band, situated on
each side of the spinal cord, throughout its entire length, and separating the ante-
rior from the posterior roots of the spinal nerves, having received its name from the
serrated appearance which it presents. Its inner border is continuous with the pia
mater, at the side of the cord. Its outer border presents a series of triangular,
dentated serrations, the points of which are fixed, at intervals, to the dura mater,
serving to unite together the two layers of the arachnoid membrane. These
serrations are about twenty in number, on each side, the first being attached to
the dura mater, opposite the margin of the foramen magnum, between the verte-
bral artery and the hypoglossal nerve; and the last corresponds to nearly the
lower end of the cord. Its use is to support the cord in the fluid by which it is
surrounded.
SPINAL CORD.
445
The Spinal Cord.
The spinal cord {medulla spinalis) is that elongated part of the cerebro-
spinal axis, which is contained in the spinal canal. It weighs, when divested
of its membranes and nerves, about one ounce and a half, its i^roportion to
the encephalon being about i to 33. It does not nearly fill the canal in
which it is contained, its investing membranes being separated from the bony-
walls of the canal by areolar tissue and a plexus of veins. It occupies, in the
adult, the upper two-thirds of the spinal canal, extending from the foramen maf-
num to the lower border of the body of the first lumbar vertebra, where it
terminates in a jDointed extremity which is concealed among the leash of nerves
forming the cauda equina. In the foetus, before the third month, it reaches to
the bottom of the vertebral canal; but, after this period, it gradually recedes from
below, as the growth of the bones composing the canal is more rapid in propor-
tion than the cord; so that, in the child at birth, it extends as far as the third
lumbar vertebra. Its position varies according to the degree of curvature of the
spinal column, being raised somewhat in flexion of the spine forwards. Its length
varies from fifteen to eighteen inches, and it presents a difference in its diameter
in different parts, being marked by two enlargements, an upper or cervical, and a
lowei', or lumbar. The cervical enlargement, which is the larger, extends from
the third cervical to the first dorsal vertebra: its greatest diameter is in the
transverse direction, and it corresponds with the origin of the nerves which
supply the upper extremities. The lower, or lumbar enlargement, is situated
opposite the last dorsal vertebra, its greatest diameter being from before back-
wards. It corresponds with the origin of the nerves which supply the lower
extremities. In form, the spinal cord is a flattened cylinder. Its anterior surface
presents, along the middle line, a longitudinal fissure, the anterior median fissure;
and, on its posterior surface, another fissure exists, which also extends along the
entire length of the cord, the posterior median fissure. These fissures serve to
divide the cord into two equal and symmetrical portions, which are connected
together throughout their entire length, by a transverse band of nervous sub-
stance, the commissure.
The Anterior median Jis sure is wider, but of less
depth than the posterior, extending into the cord for
about one-third of its thickness, and is deepest at
the lower part of the cord. It contains a prolonga-
tion from the pia mater; and its floor is formed by
the anterior white commissure, which is perforated by
numerous blood-vessels, which pass to the centre of
the cord.
The Posterior median fissure is much more deli-
cate than the anterior, and more distinct at the upper
part of the cord and below. It extends into the
cord to about one half of its depth. It contains a
very slender process of the pia mater and numerous
blood-vessels, and its floor is formed by a thin layer
of white substance, the posterior white commissure.
Some anatomists state, that the bottom of this fissure
corresponds to the grey matter, except in the cervical
corresponding to the enlargement in the lumbar region.
On either side of the anterior median fissure, a linear series of foramina may be
observed, indicating the points where the anterior roots of the spinal nerves emerge
from the cord. This is called, by some anatomists, the anterior Mteral fissure of
the cord, although no actual fissure exists in this situation. And on either side of
the posterior median fissure, along the line of attachment of the posterior roots of
the nerves, a delicate fissure may be seen, leading down to the grey matter which
approaches the surface in this situation: this is called the posterior lateral fissure
235. — Spinal Cord. Side View.
Plan of the Fissures and
Columns.
region, and at a point
446 NERVOUS SYSTEM.
of the spinal cord. On the posterior surface of the spinal cord, on either side of
the posterior median fissure, is a slight longitudinal furrow, marking off two
slender tracts, the posterior median columns. These are most distinct in the
cervical region, but are stated by Foville to exist throughout the whole length of
the cord. The fissures divide each half of the spinal cord into four columns, an an-
terior column, a lateral column, a posterior column, and a posterior median column.
The Anterior column includes all the portion of the cord between the anterior
median fissure and the anterior lateral fissure, from which the anterior roots of
the nerves arise, and is continuous with the anterior pyramid of the medulla
oblongata.
The Lateral column, the largest segment of the cord, includes all the portion
between the anterior and posterior lateral fissures. It is continuous with the
lateral column of the medulla. By some anatomists, the anterior and lateral
columns are included together, under the name of the antero-lateral column,
which forms rather more than two-thirds of the entire circumference of the cord.
The Posterior column is situated between the posterior median and poste-
rior lateral fissures. It is continued, above, into the restiform body of the
medulla.
The Posterior median column is that narrow segment of the cord which is seen
on each side of the posterior median fissure, usually included with the preceding,
as the posterior column.
If a transverse section of the spinal cord be made, it will be seen to consist of
white and grey nervous matter. The white matter is situated at the circum-
ference, the grey matter in the interior.
The Grey matter presents two crescentic masses, placed one in each lateral half
of the cord, with their convexities towards one another, and joined by a transverse
band of grey matter, the grey commissure. Each crescentic mass has an anterior
and postei'ior horn.
The posterior horn is long and narrow, and approaches the surface at the pos-
terior lateral fissurej near which it presents a slight enlargement. The grey matter,
in this situation, is pale and soft, and was called by Rolando, the substantia
cinerea gelatinosa, being surrounded by a layer of reddish-brown substance.
The anterior horn is short and thick, and does not quite reach the surface, but
extends towards the point of attachment of the anterior roots of the nerves. Its
margin presents a dentate, or stellate appearance. Owing to this peculiar arrange-
ment of the grey matter, the anterior and posterior horns projecting towards the
surface, each half of the cord is divided, more or less completely, into three
columns, anterior, middle, and posterior; the anterior and middle being joined, as
the anterior horn does not quite reach the surface, to form the antero-lateral
column.
The Grey commissure, which connects the two crescentic masses of grey
matter, is separated from the bottom of the anterior median fissure by a thick
layer of white substance, the anterior white commissure; and, from the bottom of
the posterior fissure by the posterior white commissure. The existence of the
latter commissure is doubted by some anatomists. The grey commissure con-
sists of a transverse band of grey matter, and of white fibres, derived from
the opposite half of the cord and the posterior roots of the nerves. The white
commissure is formed, partly of fibres from the anterior column, and partly
from the fibrils of the anterior roots of the spinal nerves, which decussate
as they pass across from one to the other side.
The mode of arrangement of the grey matter, and its amount in proportion to
the white, vary in different parts of the cord. Thus, the posterior horns are long
and narrow, in the cervical region; short and narrower, in the dorsal; short, but
wider, in the lumbar region. In the cervical region, the crescentic portions are
small, the white matter more abundant than in any other region of the cord. In
the dorsal region, the grey matter is least developed, the white matter being also
small in quantity. In the lumbar region, the grey matter is more abundant than
MEMBRANES OF THE BRAIN. 447
in any other region of the cord. Towards the lower end of the cord, the white
matter gradually ceases. The crescentic portions of the grey matter gradually
blend into a single mass, which forms the only constituent of its extreme
point.
The tvhite matter of the cord forms about seven-eighths of its entire substance.
It is composed of parallel fibres collected into compressed, longitudinal bundles
between which blood-vessels, supported by a deli-
cate pi-ocess of pia mater, pass transversely into the ^3(5. Transverse Sections of
substance of the cord. ^^^ ^°'"'^-
hi the fcetus, until after the sixth month, a canal,
continuous with the general ventricular cavity of
the brain, extends throughout the entire length of
the spinal cord, formed by the closing-in of a pre-
\ ox Opposite^ Middle of Cervical fea:"
viously open groove. -'■■
In the adult, this canal can only be seen at the
upper part of the cord, extending from the point
of the calamus scriptorius, in the floor of the fourth
ventricle, for about half an inch down the centre
of the cord, where it terminates in a cul de sac, « ^ xr-u? ^ r> 7
' , ' OjjpusLte MLdAlc ap Doraal regit
the remnant of the canal being just visible in- a
section of the cord, as a small, pale spot, corre-
sponding to the centre of the grey commissure, its
cavity having become obliterated. In some cases
this canal remains pervious throughout the whole ,, .^ ^T~^^
i- o Uppositt Lumbar region/
length of the cord.
The Brain and its Membranes.
Dissection. To examine the brain with its membranes, the skull cap should first be
removed. This may be eff'ected by sawing through the external table, commencing, in
front, about an inch above the margin of the orbit, and extending, behind, to a level with
the occipital protuberance. The internal table must then be broken through with the
chisel and hammer to prevent injury to the investing membi-anes or brain, and after having
been loosened, it should be forcibly detached, when the dura mater will be exposed. The
adhesion between the bone and the dura mater is very intimate, and much more so in the
young subject than in the adult.
The membranes of the brain are the dura mater, arachnoid membrane, and pia
mater.
Dura Mater.
The dura mater is a thick and dense inelastic fibrous membrane, which lines the
interior of the skull. Its outer surface is rough and fibrillated, and adheres closely
to the inner surface of the bones, forming their internal periosteum; this adhesion
being more intimate opposite the sutures and at the base of the skull, where it is
attached to the margin of the foramen magnum, and is here continuous with the
dura mater lining the spinal canal. Its inner surface is smooth and epithe-
liated, being lined by the parietal layer of the arachnoid. The dura mater is
therefore a fibro-serous membrane, composed of an external fibrous lamella,
and an internal serous layer. It sends numerous processes inwards, into
the cavity of the skull, for the support and protection of the different parts
of the brain; it is also prolonged to the outer surface of the skull, through the
various foramina which exist at its base, where it is continuous with the peri-
cranium, and its fibrous layer forms sheaths for the nerves which pass through
these apertures. At the base of the skull, it sends a fibrous prolongation into the
foramen caecum ; it lines the olfactory groove, and sends a series of tubular pro-
longations around the filaments of the olfactory nerves as they pass through the
cribriform foramina; a prolongation is also continued through the sphenoidal
fissure into the orbit, and another is continued into the same cavity through the
optic foramen, forming a sheath for the optic nerve, which is continued as far as
448 NERVOUS SYSTEM.
the eye-ball. In certain situations in the skull already mentioned, the fibrous
layer of this membrane subdivides into two, to form the sinuses for the passage of
venous blood. Upon the upper surface of the dura mater, in the situation of the
longitudinal sinus, may be seen numerous small whitish bodies, the glandulas
Pacchioni.
Structure. The dura mater consists of white fibrous and elastic tissues, arranged
in fiattened laminae, which intersect one another in every direction.
Its arteries are very numerous, but are chiefly distributed to the bones. Those
found in the anterior fossa, are the anterior meningeal, from the anterior and pos-
terior ethmoidal, and internal carotid. In the middle fossa are the middle and
small meningeal, from the internal maxillary, and a third branch from the ascending
pharyngeal, which enters the skull through the foramen lacerum basis cranii. In
the posterior fossa, are the posterior meningeal branch of the occipital, which
enters the skull through the jugular foramen, the posterior meningeal, from the
vertebral, and occasionally meningeal branches from the ascending pharyngeal,
which enter the skull, one at the jugular foramen, the other at the anterior condy-
loid foramen.
The veins which return the blood from the dura mater and partly from the
bones, anastomose with the diploic veins. These vessels terminate in the various
sinuses, with the exception of two which accompany the middle meningeal artery:
these pass from the skull at the foramen spinosum.
The tierves of the dura mater, are the recurrent branch of the fourth, and fila-
ments from the Gasserian ganglion, the ophthalmic nerve, and sympathetic.
The so-called Glandulas Pacchioni are numerous small whitish granulations,
usually collected into clusters of variable size, which are found in the following
situations: I. Upon the outer surface of the dura mater, in the vicinity of the
superior longitudinal sinus, being received into little depressions on the inner sur-
face of the calvarium. 2. On the inner surface of the dura mater. 3. In the supe-
rior longitudinal sinus. 4. On the pia mater near the margin of the hemispheres.
These bodies are not glandular in structure, but consist of a fibro-cellular matrix
originally developed from the pia mater: by their growth they produce absorption
or separation of the fibres of the dura mater; in a similar manner they make their
way into the superior longitudinal sinus, where they are covered by the lining
membrane. The cerebral layer of the arachnoid in the situation of these growths
is usually thickened and opaque, and adherent to the parietal portion.
These bodies are not found in infancy, and very rarely until the third year.
They are usually found after the seventh year; and from this period they increase
in number as age advances. Occasionally they are wanting.
Processes of the Dura Mater.
The processes of the dura mater, sent inwards into the cavity of the skull, are
three in number, the falx cerebri, the tentorium cerebelli, and the falx cerebelli.
The/a/a? cerebri, so named from its sickle-like form, is a strong arched process
of the dura mater, which descends vertically in the longitudinal fissure between
the two hemispheres of the brain. It is narrow in front, where it is attached to
the crista galli process of the ethmoid bone, and broad behind, where it is con-
nected with the upper surface of the tentorium. Its upper margin is convex, and
attached to the inner surface of the skull as far back as the internal occipital pro-
tuberance. In this situation it is broad, and contains the superior longitudinal
sinus. Its lower margin is free, concave, and presents a sharp curved edge which
contains the inferior longitudinal sinus.
The tentorium cerebelli, so named from its tent-like form, is a roof of dura mater,
elevated in the middle, and inclining downwards towards its circumference. It
covers the upper surface of the cerebellum, supporting the posterior lobes of the
brain, and preventing their pressure upon it. It is attached behind, by its convex
border, to the transverse ridges upon the inner surface of the occipital bone, and
there encloses the lateral sinuses; in front, to the superior margin of the petrous
MEMBRANES OF THE BRAIN.
449
portion of the temporal bone, enclosing the superior petrosal sinuses, and from the
apex of this bone, on each side, is continued into the anterior and posterior clinoid
processes. Along the middle line of its upper surface, the posterior border of the
falx cerebri is attached, the straight sinus being placed at their point of junction.
Its anterior border is free and concave, and presents a large oval opening for the
transmission of the crura cerebri.
The falx cei'ehelli is a small triangular process of dura mater, received into
the indentation between the two lateral lobes of the cerebellum behind. Its
base is attached, above, to the under and back part of the tentorium; its posterior
margin, to the lower division of the vertical crest on the inner surface of the
occipital bone. As it descends, it sometimes divides into two smaller folds, which
are lost on the sides of the foramen magnum.
Arachnoid Membrane.
The arachnoid {apayyit]^ €l8o<;, like a spider's web), so named from its extreme
thinness, is the serous membrane which envelopes the brain, and is then reflected
on the inner surface of the dura mater. Like other serous membranes, it is a
shut sac, and consists of a parietal and a visceral layer.
The parietal layer covers the inner surface of the dura mater, to which it is
very intimately adherent, and gives this membrane the smooth and polished surface
which it presents; it is also reflected over those processes which separate the hemi-
spheres of the brain and cerebellum.
The visceral layer invests the brain more loosely, being separated from direct
contact with the cerebral matter by the pia mater, and a quantity of loose areolar
tissue, the sub-arachnoidean. On the upper surface of the cerebrum the arachnoid
is thin and transparent, and may be easily demonstrated by injecting a stream of
air beneath it by means of a blowpipe; it passes over the convolutions without
dipping down into the sulci betv/een them. At the base of the brain, the arach-
noid is thicker, and slightly opaque towards the central part; it covers the ante-
rior lobes, is extended across between the two middle lobes, so as to leave a
considerable interval between it and the brain, the anterior suh-arachnoidean
space; it is closely adherent to the pons and under surface of the cerebellum, but
between the hemisj)heres of the cerebellum and the medulla oblongata another
considerable interval is left between it and the brain, called the posterior
sub-arachnoidean space. These two spaces communicate together across the
crura cerebri. The arachnoid membrane surrounds the nerves which arise from
the brain, and encloses them in loose sheaths as far as their point of exit from the
skull, where it becomes continuous with the parietal layer.
The Sub-arachnoid Space is the interval left between the arachnoid and pia
mater: this space is narrow on the surface of the hemispheres, but at the base of
the brain a wide interval is left between the two middle lobes, and behind, be-
tween the hemisj^heres of the cerebellum and the medulla oblongata. This space
is the seat of an abundant serous secretion, the cerebro-spinal fluid, which fills up
the interval between the arachnoid and pia mater. The sub-arachnoid space
usually communicates with the general ventricular cavity of the brain, by means
of an opening in the inferior boundary of the fourth ventricle.
The sac of the arachnoid also contains serous fluid; this is, however, small in
quantity compared with the cerebro-spinal fluid.
Structure. The arachnoid consists of bundles of white fibrous and elastic
tissues intimately blended together. The visceral portion is covered with a layer
of scaly epithelium. It is almost destitute of vessels, and the existence of nerves
in it has not been satisfactorily demonstrated.
' The Cerebro-spinal Fluid fills up the sub-arachnoid space, keeping the opposed
surfaces of the arachnoid membrane in contact. It is a clear limpid fluid, having
a saltish taste, and a slightly alkaline reaction. According to Lassaigne, it con-
sists of 98*5 parts of water, the remaining 1*5 per cent, being solid matters,
animal and saline. It varies in quantity from two to ten ounces, being most abun-
G G
450 NERVOUS SYSTEM.
dant in old persons, and is quickly reproduced. Its chief use is probably to afford
mechanical protection to the nervous centres, and to prevent the effects of concus-
sion communicated from without.
PiA Mater.
The pia mater is a vascular membrane, and derives its blood from the internal
carotid and vertebral arteries. It consists of a minute plexus of blood-vessels,
held together by an extremely fine areolar tissue. It invests the entire surface
of the brain, dipping down between the convolutions and laminae, and is prolonged
into the interior, forming the velum interpositum and choroid plexuses of the
fourth ventricle. Upon the surface of the hemispheres, where it covers the grey
matter of the convolutions, it is very vascular, and gives off from its inner sur-
face a multitude of minute vessels, which extend perpendicularly for some distance
into the cerebral substance. At the base of the brain, in the situation of the sub-
stantia perforata and locus perforatus, a number of long straight vessels are given
off, which pass through the white matter to reach the grey substance in the inte-
rior. On the cerebellum, the membrane is more delicate, and the vessels from its
inner surface are shorter. Upon the crura cerebri and pons Varolii its characters
are altogether changed; it here presents a dense fibrous structure, marked only
by slight traces of vascularity.
According to Fohmann and Arnold, this membrane contains numerous lym-
phatic vessels. Its nerves are derived from the sympathetic, and also from the
third, sixth, seventh, eighth, and accessorius. They accompany the branches of
the arteries.
The Brain.
The brain {encephalon) is that portion of the cerebro- spinal axis that is con-
tained in the cranial cavity. It is divided into four principal parts: viz., the
cei-ebrum, the cerebellum, the pons Varolii, and medulla oblongata.
The Cerebrum forms the largest portion of the encephalic mass, and occupies
a considerable part of the cavity of the cranium, resting in the anterior and
middle foss^ of the base of the skull, and separated posteriorly from the cere-
bellum by the tentorium cerebelli. About the middle of its under surface is a
narrow constricted portion, part of which, the crura cerebri, is continued onwards
into -the pons Varolii below, and through it to the medulla oblongata and spinal
cord; whilst another portion, the crura cerebelli, pass down into the cerebellum.
The Cerebellum (little brain or after brain) is situated in the inferior occipital
fossae, being separated from the under surface of the posterior lobes of the cere-
brum by the tentorium cerebelli. It is connected to the rest of the encephalic
mass by means of connecting bands, called crura; of these, two ascend to the
cerebrum, two descend to the medulla oblongata, and two blend together in front,
forming the pons Varolii.
The Pons Varolii is that portion of the encephalic mass which rests upon the
upper part of the basilar process. It constitutes a sort of centre to the various
segments above named, receiving, above, the crura from the cerebrum; at the
sides, the crura from the cerebellum; and, being connected, below, with the medulla
oblongata.
The Medulla Oblongata extends from the lower border of the pons Varolii to
the upper part of the spinal cord. It lies beneath the cerebellum, resting on the
lower part of the basilar groove of the occipital bone.
JVeight of the Encephalon. The average weight of the brain in the adult male
is 49^ oz., or a little more than 3 lb. avoirdupois, that of the female 44 oz., the
average difference between the two being from 5 to 6 oz. The prevailing
weight of the brain in the male ranges between 46 oz. and 53 oz., and in the
female, between 41 oz. and 47 oz. In the male, the maximum weight out of
278 cases was 65 oz., and the minimum weight 34 oz. The maximum weight of
the adult female brain, out of 191 cases, was 56 oz,, and the minimum weight
MEDULLA OBLONGATA.
451
3 1 oz. It appears that the weight of the brain increases rapidly up to the seventh
year, more slowly to between sixteen and twenty, and still more slowly to between
thirty and forty, when it reaches its maximum. Beyond this period, as age ad-
vances and the mental faculties decline, the brain diminishes slowly in weight
about an ounce for each subsequent decennial period. These results apply alike
to both sexes.
The size of the brain appears to bear a general relation to the intellectual capa-
. city of the individual. Cuvier's brain weighed rather more than 64 oz., that of
the late Dr. Abercrombie 63 oz., and that of Dupuytren 62|- oz. On the other
hand, the brain of an idiot seldom weighs more than 23 oz.
The human braiti is heavier than that of all the lower animals excepting
the elephant and whale. The brain of the former weighs from 8 lb. to i o lb.,
and that of the whale, in a specimen seventy-five feet long, weighed rather more
than 5 lb.
Medulla Oblongata.
The medulla oblongata is the upper enlarged part of the spinal cord, and ex-
tends from the upper border of the atlas to the lower border of the pons Varolii.
It is directed obliquely downwards and backwards, its anterior surface resting on
the basilar groove of the occipital bone, its posterior surface being received into
the fossa between the hemispheres of the cerebellum, forming the floor of the
fourth ventricle. It is pyramidal in form, its broad extremity directed up-
wards, its lower end being narrow at its point of connection with the cord. It
measures an inch and a quarter in length, three quarters of an inch in breadth at
its widest part, and half an inch in thickness. Its surface is marked in the
median line, in front and behind, by an anterior and posterior median fissure,
which are continuous with those of the spinal cord. The anterior fissure contains
a fold of pia mater, and terminates below the pons in a cul-de-sac, the foramen
caecum. The posterior is a deep but narrow fissure, continued upwards along the
floor of the fourth ventricle, where it is finally lost. These two fissures divide
the medulla into two symmetrical halves, each lateral half being subdivided by
minor grooves into four columns, which, from before backwards, are named, the
anterior pyramid, lateral tract and olivary body, the restiform body, ihQ posterior
pyramid.
The Anterior Pyramids are two
pyramidal- shaped bundles of white
matter, placed one on either side of
the anterior median fissure, and sepa-
rated from the olivary body, which is
external to them, by a slight depres-
sion. At the lower border of the
pons they are somewhat constricted;
they then become enlarged, and taper
slightly as they descend, being con-
tinuous below with the anterior co-
lumns of the cord. On separating the
pyramids below, it will be observed
that the innermost fibres of the two
form from four to five bundles on each
side, which decussate with one another;
this decussation, however, is not form-
ed entirely of fibres from the pyramids,
but mainly from the deep portion of
the lateral columns of the cord which
pass forwards to the surface between
the diverging anterior columns. The
outermost fibres do not decussate ; they
237.-
-Medulla Oblongata and Pons Varolii.
Anterior Surface.
G o 2
452
NERVOUS SYSTEM.
are derived from the anterior columns of the cord, and are continued directly up-
wards through the pons Varolii.
Lateral Tract and Olivary Body. The lateral tract is continuous with the
lateral column of the cord. Below, it is broad, and includes that part of the
medulla between the anterior pyramid and restiform body; but, above, it is
pushed a little backwards, and narrowed by the projection forwards of the olivary
body.
The Olivary Bodies are two prominent, oval masses, situated behind the ante-
rior pyramids, from which they are separated by slight grooves. They equal, in
breadth, the anterior pyramids, are a little broader above than below, and are
about half an inch in length, being separated, above, from the pons Varolii, by a
slight depression. Numerous white fibres {JibrcB arciformes) are seen winding
around the lower end of each body; sometimes crossing their surface.
The Restiform Bodies are the largest columns of the medulla, and continuous,
below, with the posterior columns of the cord. They are two rounded, cord-like
eminences, placed between the lateral tracts, in front, and the posterior pyramids,
behind; from both of which they are separated by slight grooves. As they ascend,
they diverge from each other, assist in forming the lateral boundaries of the fourth
ventricle, and then enter the corresiDonding hemisphere of the cerebellum, forming
its inferior peduncle.
The Posterior Pyramids {fasciculi graciles^ are two narrow, white cords, placed
one on each side of the posterior median fissure, and separated from the restiform
bodies by a narrow groove. They consist entirely of white fibres, and are con-
tinuous with the posterior median columns of the spinal cord. These bodies lie
at first, in close contact. Opposite the apex 238.— Posterior Surface of Medulla
of the fourth ventricle, they form an en- Oblongata.
largement {processus clavatus), and then,
diverging, are lost in the corresponding
restiform body. The upper part of the
posterior pyramids form the lateral bounda-
ries of the calamus scriptorius.
The Posterior surface of the Medulla
Oblongata forms part of the floor of the
fourth ventricle. It is of a triangular form,
bounded on each side by the diverging pos-
terior pyramids, and is that part of the
ventricle which, from its resemblance to the
point of a pen, is called the calamus scrip-
torius. The divergence of these columns,
and the restiform bodies, opens to view the
grey matter of the medulla, which is con-
tinuous, below, with the grey commissure of
the cord. In the middle line is seen a
longitudinal furrow, continuous with the
posterior median fissure of the cord, termi-
nating, below, at the point of the ventricle,
in a cul-de-sac, the ventricle of Arantius,
which descends into the medulla for a slight
extent. It is the remains of a canal, which, in the fcctus, extends throughout the
the entire length of the cord.
Structure. The columns of the cord are directly continuous with those of the
medulla oblongata, below; but, higher up, both the white and grey constitu-
ents are re-arranged before they are continued upwards to the cerebrum and
cerebellum.
The Anterior Pyramid is composed of fibres derived from the anterior column
of the cord of its own side, and from the lateral column of the opposite half of
the cord, and is continued upwards into the cerebrum and cerebellum. The
1
STRUCTURE OF MEDULLA OBLONGATA.
453
239. — Transverse Section of
Medulla Oblongata.
Fusctculi Teretea
Tosferuir Ft -itrr
cerebellar fibres form a superficial and deep layer, which pass beneath the
olive to the restiform body, and spread out into the structure of the cerebellum.
A deeper fasciculus encloses the olivary body, and, receiving fibres from it,
enters the pons as the olivaiy fasciculus or
fillet; but the chief mass of fibres from the
pyramid, the cerebral fibres, enter the pons
in their passage upwards to the cerebrum.
The anterior pyramids contain no grey
matter.
The Lateral Tract is continuous, be-
low, with the lateral column of the cord.
Its fibres pass in three different directions.
The most external join the restiform body,
and pass to the cerebellum. The internal, more numerous, pass forwards,
pushing aside the fibres of the anterior column, and form part of the opposite
anterior pyramid. The middle fibres ascend, beneath the olivary body, to the
cerebrum, passing along the back of the pons, and form, together with fibres from
the restiform body, ihe fasciculi teretes, in the floor of the fourth ventricle.
AnterLor Flss^LTl
fflivrtrij Body
A-ntertoT FyrnrwCS
240. — The Columns of the Medulla Oblongata, and their Connection with the
Cerebrum and Cerebellum.
e b r I,
^/^ Medulla Oblongata
Olivary Body. It a transverse section is made through either olivary body,
it will be found to be a small ganglionic mass, deeply imbedded in the medulla,
partly appearing on the surface as a smooth, olive-shaped eminence (fig. 239). It
consists, externally, of white substance; and internally, of a grey nucleus, the corpus
dentatum. The grey matter is arranged in the form of a hollow capsule, open
at its upper and inner part^ and presenting a zig-zag, or dentated outline. White
fibres originate from the interior of this body, by the aperture in the posterior
part of the capsule. They join with those fibres of the anterior column which
ascend on the outer side, and beneath the olive, to form the olivary fasciculus,
which ascends to the cerebrum.
The Restiform. Body is formed chiefly of fibres from the posterior column of the
454 NEEVOUS SYSTEM.
cord; but it receives some from the lateral column, and a fasciculus from the
anterior, and is continued, upwards, to the cerebrum and cerebellum. On enter-
ing the pons, it divides into two fasciculi, above the point of the fourth ventricle.
The most external one enters the cerebellum : the inner one joins the posterior
pyramid, is continued up along the fourth ventricle, and, joining the fasciculi
teretes, passes up to the cerebrum.
Septum of the Medulla Oblongata. Above the decussation of the anterior
pyramids, numerous white fibres extend, from behind forwards, in the median
line, forming a septum, which subdivides the medulla into two lateral halves.
Some of these fibres emerge at the anterior median fissure, and form a band which
curves around the lower border of the olivary body, or passes transversely across
it, and round the sides of the medulla, forming the arciform fibres of Rolando.
Others appear in the floor of the fourth ventricle, issuing fi'om the posterior
median fissure, and form the white strife in that situation.
Grey Matter of the Medulla Oblongata. The grey matter of the medulla, is a
continuation of that contained in the interior of the spinal cord, besides a series
of special deposits, or nuclei.
In the lower part of the medulla the grey matter is arranged as in the cord,
but, at the upper part, it becomes more abundant, and is disposed with less
apparent regularity, becoming blended with all the white fibres, except the
anterior pyramids. The part corresponding to the transverse grey commissure of
the cord, is exposed to view in the floor of the medulla oblongata, by the diverg-
ence of the restiform bodies, and posterior pyramids, becoming blended with the
ascending fibres of the lateral column, and thus forming the fasciculi teretes.
The lateral crescentic portions but especially the posterior horns, become enlarged,
blend with the fibres of the restiform bodies, and form the tuberculo cinereo of
Rolando.
Special deposits of grey matter are found both in the anterior and posterior
parts of the medulla; in the former situation, forming the corpus dentatum
within the olivary body, and in the latter, a series of special masses, or nuclei,
connected with the roots of origin of the spinal accessory, vagus, glosso-pharyn-
geal, and hypo-glossal nerves.
Pons Varolii.
The pons Varolii {mesocephale, Chaussier) is the bond of union of the various
segments of the encephalon, connecting the cerebrum above, the medulla oblongata
below, and the cerebellum behind. It is situated above the medulla oblongata,
below the crura cerebri, and between the hemisj)heres of the cerebellum.
Its under surface presents a broad transverse band of white fibres, which arches
like a bridge across the upper part of the medulla, extending between the two
hemispheres of the cerebellum. This surface projects considerably beyond the
level of these parts, is of a quadrangular form, rests upon the basilar groove of
the occipital bone, and is limited before and behind by very prominent mai'gins.
It presents along the middle line a longitudinal groove, Avider in front than behind,
which lodges the basilar artery; numerous transverse stria3 are also observed on
each side, which indicate the course of its superficial fibres.
Its upper surface forms part of the floor of the fourth ventricle, and at each side
it becomes contracted into a thick rounded cord, the crus cerebelli, which enters
the substance of the cerebellum, constituting its middle peduncle.
Structure. The pons Varolii consists of alternate layers of transverse and longi-
tudinal fibres intermixed with grey matter (fig. 240).
The transverse fibres connect together the two lateral hemispheres of the cere-
bellum, and constitute its great transverse commissure. They consist of a super-
ficial and a deep layer. The superficial layer passes uninterrui^tedly across the
surface of the pons, forming a uniform layer, consisting of fibres derived from the
crus cerebelli on each side, which meet in the median line. The deep layer of
PONS VAROLII. 455
transverse fibres decussate with the longitudinal fibres continued up from the
medulla; they also connect the hemisplieres of the cerebellum.
The longitudinal Jibres are continued up through the pons, I. From the ante-
rior pyramidal body. 2. From the olivary body. 3. From tlie lateral and
IDOstei'ior columns of the cord, receiving special fibres from the grey matter of the
pons itself.
1. The fibres from the anterior pyramid ascend through the pons, embedded
between two layers of transverse fibres, being subdivided in their course into
smaller bundles; at the upper border of the pons they enter the crus cerebri,
forming its fasciculated portion.
2. The olivary fasciculus divides in the pons into two bundles, one of which
ascends to the corpora quadrigemina; the other is continued to the cerebrum with
the fibres of the lateral column.
3. The fibres from the lateral and posterior columns of the cord, with a bundle
from the olivary fasciculus, are intermixed with much grey matter, and appear in
the floor of the fourth ventricle as the fasciculi teretes, they ascend to the deep or
cerebral part of the crus cerebri.
Septum. The pons is subdivided into two lateral halves by a median septum,
which extends through its posterior half. The septum consists of antero-posterior
and transverse fibres. The former are derived from the floor of the fourth ven-
tricle and from the transverse fibres of the pons, which bend backwards before
passing across to the opposite side. The latter are derived from the floor of the
fourth ventricle, they pierce the longitudinal fibres, and are then continued across
from one to the other side of the medulla, piercing the antero-posterior fibres.
The two halves of the pons, in front, are connected together by transverse com-
misural fibres.
Cerebrum. Upper -^ Surface.
The cerebrum, in man, constitutes the largest portion of the encephalon. Its
upper surface is of an ovoidal form, broader behind than in front, convex in its
general outline, and divided into two lateral halves or hemispheres, right and left,
by the great longitudinal fissure. This fissure extends throughout the entire
length of the cerebrum in the middle line, reaching down to the base of the brain
in front and behind, but interrupted in the middle by a broad transverse com-
missure of white matter, the corpus callosum, which connects the two hemi-
spheres together. This fissure lodges the falx cerebri, and indicates the original
development of the brain by two lateral halves.
Each hemisphere presents an outer surface, which is convex to correspond with
the vault of the cranium; an inner surface, flattened, and in contact with the oppo-
site hemisphere, the two forming the sides of the longitudinal fissure; and an
under surface or base, of more irregular form, which rests, in front, in the anterior
and middle fossae at the base of the skull, and behind, upon the tentorium.
Convolutions. If the pia mater is removed with the forceps, the entire surface
of each hemisphere will present a number of convoluted eminences, the convolu-
tions, separated from each other by depressions {sulci') of various depths. The
outer surface of each convolution, as well as the sides and bottom of the sulci
between them, are composed of grey matter, which is here called the cortical
substance. The interior of each convolution is composed of white matter, white
fibres also blend with the grey matter at the sides and bottom of the sulci. By
this arrangement the convolutions are admirably adapted to increase the amount
of grey matter without occupying much additional space, and also afibrd a greater
extent of surface for the fibres to terminate in it. On closer examination, however,
the grey matter of the cortical substance is found subdivided into four layers, two
of which are composed of grey and two of white substance. The most external
is an outer white stratum, not equally thick over all parts of the brain, being most
marked on the convolutions in the longitudinal fissure and on the under part of
the brain, especially on the middle lobe, near the descending horn of the lateral
456
NERVOUS SYSTEM.
ventricle. Beneath the latter is a thick reddish grey lamina, and then another thin
white stratum; lastly, a thin stratum of grey matter, which lies in close contact
with the white fibres of the hemispheres: consequently white and grey laminas
alternate with one another in the grey matter of the convolutions. In certain
convolutions, however, the cortical substance consists of no less than six layers,
three grey and three white, an additional white stratum dividing the most super-
ficial grey one into two; this is especially marked in those convolutions which
are situated near the corpus callosum.
A perfect resemblance between the convolutions does not exist in all brains, nor
are they symmetrical on the two sides of the same brain. Occasionally the free
borders or the sides of a deep convolution present a fissured or notched ap-
pearance.
The sulci are generally an inch in depth; they also vary in different brains, and
in different parts of the same brain; they are usually deepest on the outer convex
24.T. — Upper Surface of the Brain, the Pia Mater having been removed.
Great J^oni/iludiiiaZ Fissure
surface of the hemispheres; the deepest is situated on the inner surface of the
hemisphere, on a level with the corpus callosum, and corresponds to the projection
in the posterior horn of the lateral ventricle, the hippocampus minor.
The number and extent of the convolutions, as well as their depth, appear to
bear a close relation to the intellectual power of the individual, as is shown in
their increasing complexity of aiTangement as we ascend from the lowest mam-
malia up to man. Thus they are absent in some of the lower orders of this class,
and they increase in number and extent through the higher orders. In man they
BASE OF THE BRAIN. 457
present tlie most complex arrangement. Again, in tlie child at birth before the
intellectual faculties are exercised, the convolutions have a very simple arrange-
ment, presenting few undulations; and the sulci between them are less deep
than in the adult. In old age, when the mental faculties have diminished in
activity, the convolutions become much less prominently marked.
Those convolutions which are the largest and most constantly present, are the
convolution of the corpus callosum, the convolution of the longitudinal fissure, the
supra-orbital convolution, and the convolutions of the outer surface of the hemi-
sphere.
The Convolution of the Corpus Callosum {gyrus fornicatus) is always well
marked. It lies parallel with the upper surface of the corpus callosum, com-
mencing, in front, on the under surface of the brain in front of the anterior per-
forated space; it winds round the curved border of the corpus callosum, and
passes along its upper surface as far as its posterior extremity, where it is
connected with the convolutions of the posterior lobe; it then curves downwards
and forwards, embracing the cerebral peduncle, passes into the middle lobe, forming
the hippocampus major and terminates just behind the point from whence it
arose.
The Supra-orbitar Convolution on the under surface of the anterior lobe is
well marked.
The Convolution of the Longitudinal Fissure bounds the margin of the fissure
on the upper surface of the hemisphere. It commences on the under surface of
the brain, at the anterior perforated spot, passes forwards along the inner margin of
the anterior lobe, being here divided by a deep sulcus, in which the olfactory nerve
is received; it then curves over the anterior and upper surface of the hemisphere,
along the margin of the longitudinal fissure, to its posterior extremity, where it
curves forwards along the under surface of the hemisphere as far as the middle
lobe.
The convolutions on the outer convex surface of the hemisphere, the general
direction of which is more or less oblique, are the largest and the most complicated
convolutions of the brain, frequently becoming branched like the letter Y in their
course upwards and backwards towards the longitudinal fissure: these convolutions
attain their greatest development in man, and are especially characteristic of the
human brain. They are seldom symmetrical on the two sides.
Cerebrum. Under Surface or Base.
The under surface of each hemisphere presents a subdivision, as already men-
tioned, into three lobes, named, from their position, anterior, middle, and pos-
terior.
The anterior lobe, of a triangular form, with its apex backwards, is somewhat
concave, and rests upon the convex surface of the roof of the orbit, being sepa-
rated from the middle lobe by the fissure of Sylvius. The middle lobe, which is
more prominent, is received into the middle fossa of the base of the skull. The
posterior lobe rests upon the tentorium, its extent forwards being limited by the
anterior margin of the cerebellum.
The various objects exposed to view on the under surface of the cerebrum in
the middle line are here arranged in the order in which they are met with from
before backwards.
Longitudinal fissure. Tuber cinereum.
Corpus callosum and its peduncles. Infundibulum.
Lamina cinerea. Pituitary body.
Olfactory nerve. Corpora albicantia.
Fissure of Sylvius. Posterior perforated space.
Anterior perforated space. Crura cerebri.
Optic commissure.
The Longitudinal Fissure separates the two hemispheres from one another; it
458
NERVOUS SYSTEM.
divides the two anterior lobes in front; and on raising the cerebellum and pons, it
will be seen completely separating the two posterior lobes, the intermediate por-
tion of the fissure being arrested by the great transverse band of white matter,
the corpus callosum. Of these two portions of the longitudinal fissure, that which
separates the posterior lobes is the longest. In the fissure between the two ante-
rior lobes the anterior cerebral arteries may be seen ascending to the corpus
callosum; and at the back part of this portion of the fissure, the anterior curved
portion of the corpus callosum descends to the base of the brain.
24.2. — Base of the Brain.
The Corpus Callosum terminates at the base of the brain by a concave margin,
which is connected with the tuber cinereum through the intervention of a thin
layer of grey substance, the lamina cinerea. This may be exposed by gently
raising and drawing back the optic commissure. A broad white band may be
observed on each side, passing from the under surface of the corpus callosum in
front, backwards and outwards, to the commencement of the fissure of Sylvius;
these bands are called the peduncles of the corpus callosum. Laterally, the
corpus callosum extends into the anterior lobe.
The Lamina Cinerea is a thin layer of grey substance, extending backwards
from the termination of the corpus callosum above the optic commissure to the
tuber cinereum; it is continuous on either side with the grey matter of the ante-
BASE OF THE BRAIN.
459
rior perforated space, and forms the anterior part of the inferior boundary of the
third ventricle.
The Olfactory Nerve, with its bulb, is seen on either side of the longitudinal
fissure, upon the under surface of each anterior lobe.
The Fissure of Sylvius separates the anterior and middle lobes, and lodges the
middle cerebral artery. At its entrance is seen a point of medullary substance,
corresponding to a subjacent band of white fibres, connecting the anterior and
middle lobes, and called the fasciculus unciformis; on following this fissure out-
wards, it divides into two branches, which enclose a triangular- shaped prominent
cluster of isolated convolutions, the island of Reil. These convolutions, from
being covered in by the sides of the fissure, are called the gyri operti.
The Anterior Perforated Space is situated at the inner side of the fissure of
Sylvius. It is of a triangular shape, bounded in front by the convolution of
the anterior lobe and roots of the olfactory nerve; behind, by the optic tract; ex-
ternally, by the middle lobe and commencement of the fissure of Sylvius; internally,
it is continuous with the lamina cinerea, and crossed by the peduncle of the corpus
callosum. It is of a greyish colour, and corresponds to the under surface of the
corpus striatum, a large mass of grey matter, situated in the interior of the brain;
it has received its name from being perforated by numerous minute apertures for
the transmission of small straight vessels into the substance of the corpus striatum.
The Optic Commissure is situated in the middle line, immediately behind the
lamina cinerea. It is the point of junction between the two optic nerves.
Immediately behind the diverging optic tracts, and between them and the
peduncles of the cerebrum (crura cerebri) is a lozenge -shaped interval, the inter-
peduncular space, in which are found the following parts, arranged in the following
order from before backwards: the tuber cinereum, infundibulum, pituitary body,
corpora albicantia, and the posterior perforated space.
The Tuber Cinereum is an eminence of grey substance, situated between the
optic tracts and the corpora albicantia; it is connected with the surrounding parts
of the cerebrum, forms part of the floor of the third ventricle, and is continuous
with the grey substance in that cavity. From the middle of its under surface, a
conical tubular process of grey matter, about two lines in length, is continued
downwards and forwards to be attached to the posterior lobe of the pituitary
body; this is the infundibulum. Its canal, funnel-shaped in form, communicates
with that of the third ventricle.
The Pituitary Body is a small reddish-grey vascular mass, weighing from five
to ten grains, and of an oval form, situated in the sella Turcica, in connection with
which it is retained by the dura mater which forms the inner wall of the cavernous
sinus. It is very vascular, and consists of two lobes, separated from one another
by a fibrous lamina. Of these, the anterior is the larger, of an oblong form, and
somewhat concave behind, where it receives the posterior lobe, which is round.
The anterior lobe consists externally of firm yellowish-grey substance, and inter-
nally of a soft pulpy substance of a yellowish-white colour. The posterior lobe is
darker than the anterior. In the foetus it is larger proportionally than in the
adult, and contains a cavity which communicates through the infundibulum with
the third ventricle. In the adult it is firmer and more solid, and seldom contains
any cavity. Its structure, especially the anterior lobe, is similar to that of the
ductless glands.
The Corpora Albicantia are two small round white masses, each about the
size of a pea, placed side by side immediately behind the tuber cinereum. They
are formed by the anterior crura of the fornix, hence called the bulbs of the
^fornix, which, after descending to the base of the brain, are folded upon them-
selves, before passing upwards to the thalami optici. They are composed exter-
nally of white substance, and internally of grey matter; the grey matter of the
two being connected by a transverse commissure of the same material. At an
early period of foetal life they are blended together into one lai-ge mass, but
become separated about the seventh month.
46o NERVOUS SYSTEM.
The Posterior Perforated Space {Pons Tarini) corresponds to a whitish-grey
substance, placed between tlie corpora albicantia in front, the pons Varolii behind,
and the crura cerebri on either side. It forms the back part of the floor of the
third ventricle, and is perforated by numerous small orifices for the passage of
blood-vessels, to the thalami optici.
The Crura Cerebri {Peduncles of the Cerehrurn) are two thick cylindrical
bundles of white matter, which emerge from the anterior border of the pons, and
diverge as they pass forwards and outwards to enter the under part of either
hemisphere. ' Each crus is about three-quarters of an inch in length, and some-
what broader in front than behind. They are marked upon their surface with
longitudinal strige, and each is crossed, just before entering the hemisphere, by a
flattened white band, the optic tract, which is adherent by its upper border to the
peduncle. In its interior is contained a mass of dark grey matter, called locus
niger. The third nerves may be seen emerging from the inner side of either
crus; and the fourth nerve winding around its outer side from above.
Each crus consists of a superficial and deep layer of longitudinal white fibres,
continued upwards from the pons, separated by a mass of grey matter, the locus
niger.
The Superficial Longitudinal Fibres are continued upwards, from the anterior
pyramids to the cerebrum. They consist of coarse fasciculi, which form the free
part of the crus, and have received the name of the fasciculated portion of the
peduncle, or crust.
The Deep Layer of Longitudinal Fibres are continued upwards, to the cere-
brum, from the lateral and posterior columns of the medulla, and from the olivary
fasciculus, these fibres consisting of some derived from the same, and others from
the opposite lateral tract of the medulla. More deeply, are a layer of finer fibres,
mixed with grey matter, derived from the cerebellum, blended with the former.
The cerebral surface of the crus cerebri is formed of these fibres, and is named the
tegmentum.
The Locus Niger is a mass of grey matter, situated between the superficial
and deep layer of fibres above described. It is placed nearer the inner than the
outer side of this body.
The posterior lobes of the cerebrum are concealed from view by the upper
surface of the cerebellum, and pons Varolii. When these parts are removed, the
two hemispheres are seen to be separated by the great longitudinal fissure, this
fissure being arrested, in front, by the posterior rounded border of the corpus
callosum.
General Arrangement of the Parts composing the Cerebrum.
As the peduncles of the cerebrum enter the hemispheres, they diverge from
one another, so as to leave an interval between them, the interpeduncular space.
As they ascend, the component fibres of each pass through two large masses of
grey matter called the ganglia of the brain, the thalami optici, and corpora
striata, which project as rounded eminences from the upper and inner side of each
peduncle. The hemispheres are connected together, above these masses, by the
great transverse commissure, the corpus callosum, and the interval left between
its under surface, the upper surface of the ganglia, and the parts closing the
interpeduncular space, forms the general ventricular cavity. The upper part of
this cavity is subdivided into two, by a vertical septum, the septum lucidum; and
thus the two lateral ventricles are formed. The lower part of this cavity forms
the third ventricle, which communicates with the lateral ventricles, above, and
with the fourth ventricle, behind. The fifth ventricle is the interval left between
the two layers composing the septum lucidum.
Interior of the Cerebrum.
If the upper part of either hemisphere is removed with a scalpel, about half an
CORPUS CALLOSUM.
461
inch above the level of the corpus callosum, its internal white mattei* will be
exposed. It is an oval-shaped centre, of white substance, surrounded on all sides
by a narrow, convoluted margin of grey matter, which presents an equal thickness
in nearly every part. This white, central mass, has been called the centrum ovale
minus. Its surface is studded with numerous minute red dots {puncta vasculosci),
produced by the escape of blood from divided blood-vessels. In inflammation, or
great congestion of the brain, these are very numerous, and of a dark colour. If
the remaining portion of the hemispheres are slightly separated from one another,
a broad band of white substance will be observed connecting them, at the bottom
of the longitudinal fissure: this is the corpus callosum. The margins of the
hemispheres, which overlap this portion of the brain, are called the labia cerebri.
It is a part of the convolution of the corpus callosum {gyrus fornicatus), already
described; and the space between it and the upper surface of the corpus callosum,
has been termed the ventricle of the corpus callosum.
The hemispheres should now be sliced oif, to a level with the corpus callosum,
when the white substance of that structure will be seen connecting together both
hemispheres. The large expanse of medullary matter now exposed, surrounded
by the convoluted margin of grey substance, is called the centrum ovale majus of
Vieussens.
243. — Section of the Brain. Made on a Level with the Corpus Callosum.
The Corpus Callosum is a thick stratum of transverse fibres, exposed at the
bottom of the longitudinal fissure. It connects the two hemispheres of the brain,
forming their great transverse commissure; and forms the roof of a space in the
interior of each hemisphere, the lateral ventricle. " It is about four inches in
length, extending to within an inch and a half of the anterior, and to within two
462
NERVOUS SYSTEM.
inches and a half of the posterior, part of the brain. It is somewhat broader
behind than in front, and it is thicker at either end than in its central part, being
thickest behind. It presents a somewhat arched form, from before backwards,
terminating anteriorly in a rounded border, which curves downwards and back-
wards, between the anterior lobes to the base of the brain. In its course, it forms
a distinct bend, named the knee, or genu, and the reflected portion, named the
heak (rostrum), becoming gradually narrower, is attached to the anterior cerebral
lobe, and is connected, through the lamina cinerea, with the optic commissure.
The reflected portion of the corpus callosum gives oiF, near its termination, two
bundles of white substance, which, diverging from one another, pass backwards,
across the anterior perforated space, to the entrance of the fissure of Sylvius.
They are called the peduncles of the corpus callosum. Posteriorly, the corpus
callosum forms a thick, rounded fold, which is fr^e for a little distance, as it
curves forwards, and is then continuous with the fornix. On its upper surface,
its fibrous structure is very apparent to the naked eye, being collected into coarse,
transverse bundles. Along the middle line, is a linear depression, the raphe, bounded
laterally by two or more slightly elevated longitudinal bands, called the strice
longitudinales, or nerves of Lancisi; and, still more externally, other longitudinal
stride are seen, beneath the convolution, which rests on the corpus callosum. These
are the strise longitudinales laterales. The under surface of the corpus callosum
244. — The Lateral Ventricles of the Brain.
is continuous behind with the fornix, being separated from it in front by the sep-
tum lucidum, which forms a vertical partition between the two ventricles. On
LATERAL VENTRICLES. 463
either side, the fibres of the corpus callosum penetrate into the substance of the
hemispheres, and connect together the anterior, middle, and part of the posterior
lobes. It is tlie increased aggregation of fibres derived from the anterior and
posterior lobes, which explains the great thickness of the two extremities of this
commissure.
An incision should now be made through the corpus callosum, on either side of the
raphe, when two large irregular cavities will be exposed, which extend throughout the
entire length of each hemisphere. These are the lateral ventricles.
The Lateral Ventricles are serous cavities, formed by the upper part of the
general ventricular space in the interior of the brain. They are lined by a thin
diaphanous lining membrane, covered with ciliated epithelium, and moistened by a
serous fluid, which is sometimes, even in health, secreted in considerable quantity.
These cavities are two in number, one in each hemisphere, and they are sepa-
rated from each other by a vertical septum, the septum lucidum.
Each lateral ventricle consists of a central cavity, or body, and three smaller
cavities, or cornua, which extend from it in different directions. The anterior
cornu, curves forwards and outwards, into the substance of the anterior lobe. The
posterior cornu, called the digital cavity, curves backAvards into the posterior lobe.
The middle cornu, descends into the middle lobe.
The Central Cavity, or body of the lateral ventricle, is triangular in form. It
is bounded, above, by the under surface of the corpus callosum, which forms the
roof of the cavity. Internally, is a vertical partition, the septum lucidum, which
separates it from the opposite ventricle, and connects the. under surface of the
corpus callosum with the fornix. Its floor is formed by the following parts,
enumerated in their order of position, from before backwards, the corpus striatum,
taenia semicircularis, thalamus opticus, choroid plexus, corpus fimbriatum, and
fornix.
The Anterior Cornu is triangular in form, passing outwards into the anterior
lobe, and curving round the anterior extremity of the corpus striatum. It is
bounded, above and in front, by the corpus callosum; behind, by the corpus
striatum.
The Posterior Cornu, or digital cavity, curves backwards into the substance of
the posterior lobe, its direction being backwards and outwards, and then inwards.
On its floor is seen a longitudinal eminence, which corresponds with a deep sulcus
between two convolutions: this is called the hippocampus minor. Between the
middle and posterior horns, a smooth eminence is observed, which varies con-
siderably in size in different subjects. It is called the eminentia collateralis.
The Corpus Striatum (superior ganglion of the cerebrum), has received its
name from the striated appearance which its section presents, from white fibres
diverging through its substance. The intra-ventricular portion is a large pear-
shaped mass, of a grey colour externally; its broad extremity is directed forwards,
into the fore-part of the body, and anterior cornu of the lateral ventricle; its
narrow end is directed outwards and backwards, being separated from its fellow
by the thalami optici; it is covered by the serous lining of the cavity, and crossed
by some veins of considerable size. The extra-ventricular portion is imbedded
in the white substance of the hemisphere.
The Tcenia Semicircularis is a narrow, whitish, semi-transparent band, of
medullary substance, situated in the depression between the corpus striatum and
thalamus opticus. Anteriorly, it descends in connexion with the anterior pillar
of the fornix; behind, it is continued into the descending horn of the ventricle,
where it becomes lost. Its surface, especially at its fore-part, is transparent, and
dense in structure, and was called by Tarinus the horny band. It consists of
longitudinal white fibres, the deepest of which run between the corpus striatum
and thalamus opticus. Beneath it is a large vein {vena corporis striati), which
receives numerous smaller veins from the surface of the corpus striatum, and
thalamus opticus, and terminates in the venjB Galeni.
464
NERVOUS SYSTEM.
The Choroid Plexus is a highly vascular, fringe-like membrane, occupying the
margin of the fold of pia mater {velum interpositum), in the interior of the brain.
It extends, in a curved direction, across the floor of the lateral ventricle. In front,
where it is small and tapering, it communicates with the choroid plexus of the
opposite side, through a large oval aperture, the foramen of Monro. Poste-
riorly, it descends into the middle horn of the lateral ventricle, where it joins with
the pia mater through the transverse fissure. In structure, it consists of minute,
and highly vascular villous processes, the villi being covered by a single layer of
epithelium, composed of large, round corpuscles, containing, besides a central
nucleus, a bright yellow spot. The arteries of the choroid plexus enter the ven-
tricle at the descending cornu, and, after ramifying through its substance, send
branches into the substance of the brain. The veins of the choroid plexuses ter-
minate in the venae Galeni.
The Corpus Fimbriatum, or Tcenia Hippocampi, is a narrow, white, tape-like
band, situated immediately behind the choroid plexus. It is the lateral edge of
the posterior pillar of the fornix, and is attached along the inner border of the
hippocampus major as it descends into the middle horn of the lateral ventricle.
It may be traced as far as the pes hippocampi.
245, — The Fornix, Velum Interpositum, and Middle or Descending Cornu of
the Lateral Ventricle.
The Thalami Optici and Fornix will be described when more completely ex-
posed, in a later stage of the dissection of the brain.
LATERAL VENTRICLE; MIDDLE CORNU. 465
The middle cornu should now be exposed, throughout its entire extent, by introducing
the little linger gently into it, and cutting through the hemisphere, between it and the
surface, in the direction of the cavity.
The Middle, or Descending Cornu, the largest of the three, traverses the
middle lobe of the brain, forming in its course a remarkable curve round the
back of the optic thalamus. It passes, at first, backwards, outwards, and down-
wards, and then curves around the crus cerebri, forwards and inwards, nearly to
the point of the middle lobe, close to the fissure of Sylvius. Its superior bound-
ary is formed by the medullary substance of the middle lobe, and the under surface
of the thalamus opticus. Its inferior boundary presents for examination the
following parts: The hippocampus major, pes hippocampi, pes accessorius, corpus
fimbriatuni, choroid plexus, fascia dentata, transverse fissure.
The Hippocampus Major, or Cornu Ammonis, so called from its resemblance
to a ram's horn, is a white eminence, of a curved elongate form, extending along
the entire length of the floor of the middle horn of the lateral ventricle. At its
lower extremity it becomes enlarged, and presents a number of rounded elevations
with intervening depressions, which, from presenting some resemblance to the
claw of an animal, is called the pes hippocampi. If a transverse section is made
through the hippocampus major, it will be seen that this eminence is the inner
surface of the convolution of the corpus callosum, doubled upon itself like a horn,
the white convex portion projecting into the cavity of the ventricle; the grey
portion being on the surface of the cerebrum, the edge of which, slightly indented,
forms the fascia dentata. The white matter of the hippocampus major is conti-
nuous through the corpus fimbriatum, with the fornix and corpus callosum.
The Pes Accessorius, or Eminentia Collateralis, has been already mentioned, as
a white eminence, varying in size, placed between the hippocampus major and
minor, at the junction of the posterior with the descending cornu. Like the
hippocampi, it is formed by white matter corresponding to one of the sulci,
between two convolutions protruding into the cavity of the ventricle.
The Corpus Fimbriatum (^Tcznia Hippocampi), is a narrow, tape-like band,
attached along the inner concave border of the hippocampus major, and reaching
down as far as the pes hippocampi. It is a continuation of the posterior pillar of
the fornix, prolonged from the central cavity of the lateral ventricle.
Fascia Dentata. On separating the inner border of the corpus fimbriatum
from the choroid plexus, and raising the edge of the former, a serrated band of
grey substance, the edge of the grey substance of the middle lobe, will be seen
beneath it: this is the fascia dentata. Correctly speaking, it is placed external to
the cavity of the descending cornu.
The Transverse Fissure is seen on separating the corpus fimbriatum from the
thalamus opticus. It is situated beneath the fornix, extending from the middle
line behind, downwards on either side, to the end of the descending cornu, being-
bounded on one side by the fornix and the hemisphere, and on the other by the
thalamus opticus. Through this fissure the pia mater passes from the exterior of
the brain into the ventricles, to form the choroid plexuses. Where the pia mater
projects into the lateral ventricle, beneath the edge of the fornix, it is covered by
a prolongation of the lining membrane, which excludes it from the cavity.
The Septum Lucidum forms the internal boundary of the lateral ventricle. It
is a thin, semi-transparent septum, attached, above, to the under surface of the
corpus callosum; below, to the anterior part of the fornix; and, in front of this,
to the prolonged portion of the corpus callosum. It is triangular in form, broad
in front, and narrow behind, its surfaces looking towards the cavities of the
ventricles. The septum consists of two laminee, separated by a narrow interval,
the fifth ventricle.
Each lamina consists of an internal layer of white substance, covered by the
lining membrane of the fifth ventricle; and an outer layer of grey matter, covered
by the lining membrane of the lateral ventricle. The cavity of the ventricle is
lined by a serous membrane, covered with epithelium, and contains fluid. In the
H \\
466 NERVOUS SYSTEM.
foetus, and in some animals, this cavity communicates, below, with the third
ventricle; but in the adult, it forms a separate cavity. In cases of serous effusion
into the ventricles, the septum is often found softened and partially broken
down.
The fifth ventricle may be exposed by cutting through the septum, and attached portion
of the corpus callosum, with the scissors ; after examining which, the corpus callosum
should be cut across, towards its anterior part, and the two portions carefully dissected,
the one forwards, the other backwards, when the fornix will be exposed.
The Fornix is a longitudinal lamella, of fibrous matter, situated beneath the
corpus callosum, with which it is continuous behind, but separated from it in
front by the septum lucidum. It may be divided along the middle line into two
symmetrical halves, one for either hemisphere. These two portions are joined
together in the middle line, where they form the body, but are separated from one
another in front and behind; in front, foi'ming the anterior crura, and behind,
the posterior crura.
The body of the fornix is triangular in form; narrow in front, broad behind.
Its upper surface is connected, in the median line, to the septum lucidum in front,
and the corpus callosum behind. Its under surface rests upon the velum interpo-
situm, which separates it from the third ventricle, and the inner portion of the
optic thalami. Its lateral edges form, on each side, part of the floor of the lateral
ventricles, and are in contact with the choroid plexuses.
The anterior crura arch downwards towards the base of the brain, separated
from each other by a narrow interval. They are composed of white fibres, which
descend through a quantity of grey matter in the lateral walls of the third ven-
tricle, and are placed immediately behind the anterior commissure. At the base
of the brain, the white fibres of each crus forn; a sudden curve upon themselves,
spread out and form the outer part of the corresponding corpus albicans, from
which point they may be traced upwards into the substance of the corresponding
thalamus opticus. The anterior crura of the fornix are connected in their course
with the optic commissure, the white fibres covering the optic thalamus, the
peduncle of the pineal gland, and the superficial fibres of the taenia semicircu-
laris.
The posterior crura, at their commencement, are intimately connected by
their upper surfaces with the corpus callosum ; diverging from one another,
they pass dowuAvards into the descending horn of the lateral ventricle, being
continuous with the concave border of the hippocampus major. The lateral
thin edges of the posterior crura have received the name corpus Jimbriatum,
already described. On the under surface of the fornix, towards its posterior part,
between the diverging posterior crura, may be seen some transverse lines, and
others longitudinal or oblique. This appearance has been termed the lyra, from
the fancied resemblance it bears to the strings of a harp.
Between the anterior pillars of the fornix and the anterior extremities of the
thalami optici, an oval aperture is seen on each side, the foramen of Monro. The
two openings descend towards the middle line, and joining together, lead into the
upper part of the third ventricle. These openings form a transverse communica-
tion between the lateral ventricles, and below with the third ventricle.
Divide the fornix across anteriorly, and reflect the two portions, the one forwards, the
other backwards, when the velum interpositum will be exposed.
The Velum Interpositum is a vascular membrane, reflected from the pia mater
into the interior of the brain through the transverse flssure, passing beneath the
posterior rounded border of the corpus callosum and fornix, and above the corpora
quadrigemina, pineal gland, and optic thalami. It is of a triangular fonn, and
separates the under surface of the body of the fornix from the cavity of the third
ventricle. Its posterior border forms an almost complete investment for the pineal
gland. Its anterior extremity, or apex, is bifid; each bifurcation being continued
into the corresponding lateral ventricle, behind the anterior crura of the fornix,
THIRD VENTRICLE.
467
forming the anterior extremity of tlie choroid plexus. On its under surface are
two vascular fringes, which diverge from each other behind, and project into the
cavity of the third ventricle. These are the choroid plexuses of the third ven-
tricle. To its lateral margins are connected the choroid plexuses of the lateral
ventricles. The arteries of the velum interpositum enter from behind, beneath
the corpus callosum. Its veins, the venae Galeni, two in number, run along its
under surface; they are formed by the vente corporis striati and the venaB plexus
choroides: the vena3 Galeni unite posteriorly into a single trunk, which terminates
in the straight sinus.
The velum interpositum should now be removed. This must be effected carefully,
especially at its posterior part, where it invests the pineal gland ; the thalami optici will
then be exposed with the cavity of the third ventricle between them (fig. 246).
246.— The Third and Fourth Ventricles.
The Thalami Optici {Superior Ganglia of the Cerebrum) are two large
oblong masses, placed between the diverging portions of the corpora striata; they
are of a white colour superficially, internally they are composed of white fibres
intermixed with grey matter. Each thalamus rests upon its corresponding crus
cerebri, which it embraces. Externally, it is bounded by the corpus striatum and
taenia semicircularis, and is continuous with the hemisphere. Internally, it forms
the lateral boundary of the third ventricle; and running along its uj^per border is
seen the peduncle of the pineal gland. Its upper sicrfaee is free, being partly
seen in the lateral ventricle; it is partly covered by the fornix, and marked in
Hii 2
468 NERVOUS SYSTEM.
front by an eminence, the anterior tubercle. Its under surface forms the roof of
the descending cornu of the lateral ventricle; into it the crus cerebri passes. Its
posterior and inferior part, which projects into the descending horn of the lateral
ventricle, presents two small round eminences, the internal and external geniculate
bodies. Its anterior extremity, which is narrow, forms the posterior boundary of
the foramen of Monro.
The Third Ventricle is the narrow oblong fissure placed between the thalami
optici, and extending to the base of the brain. It is bounded above by the under
surface of the velum interpositum, from which are suspended the choroid plexuses
of the third ventricle, and laterally by two white tracts, one on either side, the
peduncles of the pineal gland. Its floor, somewhat oblique in its direction, is
foi'med, from before backwards, by the parts which close the interpeduncular
space, viz., the lamina cinerea, the tuber cinereum and infundibulum, the corpora
albicantia, and the locus perforatus; its sides, by the optic thalami; in front, by
the anterior crura of the fornix and part of the anterior commissure; behind, by
the posterior commissure and the iter a tertio ad quartum ventriculum.
The cavity of the third ventricle is crossed by three commissures, named, from
their position, anterior, middle, and posterior.
The Anterior Commissure is a rounded cord of white fibres, placed in front of
the anterior criara of the fornix. It perforates the corpus striatum on either side,
and spreads out into the substance of the hemispheres, over the roof of the de-
scending horn of the lateral ventricle.
The 3'Iiddle or Soft Commissure consists almost entirely of grey matter. It
connects together the thalami optici, and is continuous with the grey matter lining
the anterior part of the third ventricle.
The Posterior Commissure, smaller than the anterior, is a flattened white band
of fibres, connecting together the two thalami optici posteriorly. It bounds the
third ventricle posteriorly, and is placed in front of and beneath the pineal gland,
above the opening leading to the fourth ventricle.
The third ventricle has four openings connected with it. In front are two oval
apertures, one on either side, the foramina of Monro, through which the third
communicates with the lateral ventricles. Behind, is a third opening leading into
the fourth ventricle by a canal, the aqueduct of Sylvius, or iter a tertio ad quartum
ventriculum. The fourth, situated in the anterior part of the fioor of the ven-
tricle, is a deep pit, which leads downwards to the funnel-shaped cavity of the
infundibulum {iter ad infundibulum).
The lining membrane of the lateral ventricles is continued through the foramina
of Monro into the third ventricle, and extends along the iter a tertio into the
fourth ventricle; at the bottom of the iter ad infundibulum it ends in a cul-de-sac.
Grey Matter of the Third Ventricle. A layer of grey matter covers the greater
part of the surface of the third ventricle. In the floor of this cavity it exists in
great abundance, and is prolonged upwards on the sides of the thalami, extending
across the cavity as the soft commissure; below, it enters into the corpora albi-
cantia, surrounds in part the anterior pillars of the fornix, and ascends on the
sides of the septum lucidum.
Behind the third ventricle, and in front of the cerebellum, are the corpora
quadrigemina, and resting upon these the pineal gland.
The Pineal Gland (Conarium), so named from its peculiar shape (pinus, the
fruit of the fir), is a small reddish-grey body, conical in form, placed immediately
behind the posterior commissure, and between the nates, upon which it rests. It
is retained in its position by a duplicature of pia mater, derived from the under
surface of the velum interpositum, which almost completely invests it. The pineal
gland is about four lines in length, and from two to three in width at its base, and is
said to be larger in the child than in the adult, and in the female than in the male.
Its base is connected with the cerebrum by some transverse commissural fibres
derived from the posterior commissure, and by four slender peduncles, formed of
medullary fibres. Of these, the two superior pass forwards upon the upper and
COEFORA QUADKIGEMINA; VALVE OF VIEUSSENS. 469
inner margin of the oi^tic thalami, to the anterior crura of the fornix, with which
they become blended. The inferior peduncles pass vertically downwards from
the base of the pineal body, along the back part of the inner surface of the thalami,
and are only seen on a longitudinal vertical section through the gland. The
pineal gland is very vascular, and consists chiefly of grey matter, with a few
medullary fibres. In its base is a small cavity, said by some to communicate with
that of the third ventricle. It contains a transparent viscid fluid, and occasion-
ally a quantity of sabulous matter, named acervulus cerebri, composed of phos-
phate and carbonate of lime, phosphate of magnesia and ammonia, with a little
animal matter. These concretions are almost constant in their existence, and are
found at all periods of life. When this body is solid, the sabulous matter is found
upon its surface, and occasionally upon its peduncles.
On the removal of the pineal body and adjacent portion of pia mater, the corpora
quadrigemiua are exposed.
The Corpora or Tubercula Quadrigemina {optic lobes) are four rounded
eminences placed in pairs, two in front, two behind, and separated from another
by a crucial depression. They are situated immediately behind the third ventricle
and posterior commissure, beneath the posterior border of the corpus callosum, and
above the iter a tertio ad quartum ventriculum. The anterior pah*, the nates, are
the larger, oblong from before backwards, and of a grey colour. The posterior
pair, the testes, are hemispherical in form, and lighter in colour than the preceding.
They are connected on each side with the thalamus opticus and commencement of
the optic tracts, by means of two white prominent bands, termed brachia. Those
connecting the nates with the thalamus {brachia anteriora) are the larger, and pass
obliquely outwards. Those connecting the testes with the thalamus, are called
the brachia posteriora. Both pairs, in the adult, are quite solid, being composed
of white matter externally, and grey matter within. These bodies are larger in
the lower animals than in man. In fishes, reptiles, and birds, they are only two
in number, and called the optic lobes, from their connection with the optic nerves ;
and are hollow in their interior; but in mammalia they are four in number, as in
man, and quite solid. In the human foetus they are developed at a very early
period, and form a large proportion of the cerebral mass ; at first they are only two
in number, as in the lower mammalia, and hollow in their interior.
These bodies, from below, receive white fibres fron* the olivary fasciculus or
fillet; they are also connected with the cerebellum, by means of a lai*ge white cord
on each side, the processus ad testes, or superior peduncles of the cerebellum,
from the corpora quadrigemina, these tracts pass upwards to the thalami.
The Valve of Vieussens is a thin translucent lamina of medullary substance,
stretched between the two processus e cerebello ad testes; it covers in the canal
leading from the third to the fourth ventricle, forming part of the roof of the lat-
ter cavity. It is narrow in front, where it is connected with the testes; and broader
behind, at its connection with the vermiform process of the cerebellum. A slight
elevated ridge (the frenulum) descends upon the upper part of the valve from the
corpora quadrigemina, and on either side of it may be seen the fibres of origin of
the fourth nerve. Its lower half is covered by a thin transversely grooved lobule
of grey matter prolonged from the anterior border of the cerebellum ; this is called
the linguetta laminosa.
The Corpora Geniculata are two small flattened oblong masses, placed on the
outer side of the corpora quadrigemina, and on the under and back part of each
optic thalamus, and are named from their position, corpus geniculatum externum
and internum. They are placed one on the outer and one on the inner side of
each optic tract. In this situation, the optic tract may be seen dividing into two
bands, one of which is connected with the external geniculate body and nates, the
other being connected with the internal geniculate body and testis.
Structure of the Cerebrum. The white matter of each hemisphere consists of
three kinds of fibres, i. Diverging or peduncular fibres, which connect the hemi-
470 NERVOUS SYSTEM.
sphere with the cord and medulla oblongata. 2. Transverse commissural fibres
which connect together the two hemispheres. 3. Longitudinal commissural fibres,
which connect distant parts of the same hemisphere.
The diverging or peduncular Jibres consist of a main body and of certain acces-
sory fibres. The main body originate in the columns of the cord and medulla
oblongata, and enter the cerebrum through the crus cerebri, where they are
arranged in two bundles, separated by the locus niger. Those fibres which form
the inferior or fasciculated portion of the crus are derived from the pyramid, and
ascending, pass mainly through the centre of the striated body ; those on the oppo-
site surface of the crus, which form the tegmentum, are derived from the posterior
pyramid and fasciculi teretes; ascending, they pass, some through the under part of
the thalamus, and others through both thalamus and corpus striatum, decussating
in these bodies with each other and with the fibre's of the corpus callosum. The
optic thalami also receive accessory fibres from the processus ad testes, the olivary
fasciculus, the corpora quadrigemina, and corpora geniculata. Some of the
diverging fibres end in the cerebral ganglia, whilst others pass through and receive
additional fibres fi*om them, and as they emerge, radiate into the anterior, middle,
and posterior lobes of the hemisphere, decussating again with the fibres of the
corpus callosum, before passing to the convolutions.
The transverse commissural fibres connect together the two hemispheres across
the middle line. They are fonned by the corpus callosum and the anterior and
posterior commissures.
The longitudinal commissural fibres connect together distant parts of the same
hemisphere, the fibres being disposed in a longitudinal direction. They form the
fornix, the ttenia semicircularis, and peduncles of the pineal gland, the stride longi-
tudinales, the fibres of the gyrus fornicatus, and' the fasciculus uncinatus.
The Cerebellum.
The cerebellum or little brain, is that portion of the encephalon which is con-
tained in the inferior occipital fossae. It is situated beneath the posterior lobes of the
cerebrum, from which it is separated by the tentorium. Its average weight in the
male is 5 oz. 4 drs. It attains its maximum weight between the twenty-fifth and
fortieth years; its increase in weight after the fourteenth year being relatively
greater in the female than in the male. The proportion between the cerebellum
and cerebrum is, in the male, as i to 8f, and in the female, as i to 8-^-. In the
infant, it is proportionally much smaller than in the adult, the relation between
them being, according to Chaussier, between i to 13, and i to 26; by Cruvelhier
it was found to be i to 20. In form the cerebellum is oblong, flattened from
above downwards, its greatest diameter being from side to side. It measures
from three and a half to four inches transversely, from two to two and a half
inches from before backwards, being about two inches thick in the centre, and
about six lines at its circumference, the thinnest part. It consists of grey and
white matter, the former, darker than that of the cerebrum, occupies the surface;
the latter, the interior. The surface of the cerebellum is not convoluted like the
cerebrum, but traversed by numerous curved furrows or sulci, which vary in depth
at different parts, and correspond to the intervals between the laminge of which its
exterior is composed.
Its upper surface {^g. 247) is somewhat elevated in the median line, and depressed
towards its circumference; it consists of two lateral hemispheres, connected together
by an elevated median portion or lobe, the superior vermiform process. The
median lobe is the fundamental part, and in some animals, as fishes and reptiles,
the only part which exists, the hemispheres being additions, and attaining their
maximum in man. The hemispheres are separated in front by a deep notch, the
incisura cerebelli anterior, which encircles the corpora quadrigemina behind; they
are also separated by a similar notch behind, the incisura cerebelli posterior, in
which is received the upper part of the falx cerebelli. The superior vermiform
process (upper part of the median lobe of the cerebellum), extends from the notch
CEREBELLUM.
471
on the anterior to that on the posterior border. It is divided into thi-ee lobes ; the
lobulus centralis, a small lobe, situated in the incisura anterior; the monticulus
cerebelli, the central projecting part of the process; and the commissura simplex,
a small lobe near the incisura posterior.
247. — Upper Surface of the Gei-ebellum.
The under surface of the cerebellum (fig. 248) is subdivided into two well marked
convex lateral hemispheres by a depression, the valley, which extends from before
backwards in the middle line. The lateral hemispheres are lodged in the inferior
occipital fossae; the median depression, or valley, receives the back part of the
medulla oblongata, is broader in the centre than at either extremity, and has, pro-
jecting from its floor, part of the median lobe of the cerebellum, called the inferior
vermiform process. The parts entering into the composition of this body are,
248. — Under Surface of the Cerebellum.
from behind forwards, the commissura brevis, situated in the incisura posterior;
in front of this, a laminated conical projection, the pyramid; more anterior, a
larger eminence, the uvula; placed between the two rounded lobes which occupy
the sides of the valley, the amygdalae; and connected with them by a commissure
of grey matter, indented on the surface, and callexl i\\Qr furroiaed band. In front
of the uvula is the nodulus; it is the anterior pointed termination of the inferior
472
NERVOUS SYSTEM.
vermiform process, and projects into the cavity of the fourth ventricle; it has been
named by Malacarne the laminated tubercle. On each side of the nodule is a
thin layer of white substance, attached externally to the flocculus, and internally
to the nodule, and to a corresponding part on the opposite side; they form to-
gether the posterior medullary velum, or commissure of the flocculus. They are
usually covered in and concealed by the amygdalae, and cannot be seen until these
are drawn aside. This band is of a semilunar form on each side, its anterior
margin being free and concave, its posterior being attached just in front of the
fiu'rowed band. Between it and the nodulus and uvula behind, is a deep fossa,
called the swalloio's nest {nidus hirundinis).
Lobes of the Cerebellum. Each hemisphere is divided into an upper and a
lower portion by the great horizontal fissure, which commences in front at the
pons, and passes horizontally round the free margin of either hemisphere, back-
wards to the middle line. From this primary fissure numerous secondary fissures
pi'oceed, which separate the cerebellum into lobes.
Upon the upper surface of either hemisphere there are two lobes, separated from
each other by a fissure. These are the anterior or square lobe, which extends as
far back as the posterior edge of the vermiform process, and the posterior or semi-
lunar lobe, which passes from the termination of the preceding to the great hori-
zontal fissure.
Upon the under surface of either hemisphere there are five lobes, separated by
sulci; these are from before backwards; the Jlocculus or sub-peduncular lobe, a
prominent tuft, situated behind and below the middle peduncle of the cerebellum;
its surface is composed of grey matter, subdivided into a few small laminse: it is
sometimes called the pneumogastric lobule, from being situated behind the pneu-
mogastric nerve. The amygdala or tonsil is sityiated on either side of the great
median fissure or valley, and projects into the fourth ventricle. The digastric
lobe is situated on the outside of the tonsil, being connected in part with the
pyramid. Behind the digastric is the slender lobe, Avhich is connected with the
back part of the pyramid and the conmiissura brevis: and most posteriorly is the
inferior posterior lobe, which also joins the commissura brevis in the valley.
Fourth Ventricle.
The fourth ventricle, or ventricle of the cerebellum, is the space between the
posterior surface of the medulla oblongata and pons in front, and the cerebellum
behind. It is lozenge-shaped, being contracted above and below, and broadest
across its central part. It is bounded laterally by the processus e cerebello ad
testes above, and by the diverging posterior pyramids and restiform bodies below.
The roof IS arched; it is formed by the valve of Vieussens and the under sur-
face of the cerebellum, Avhich presents in this situation four small eminences or
lobules, two occupying the median line, the nodulus and uvula, the remaining two,
the amygdala, being placed on either side of the uvula.
The anterior boundary, ov floor, is formed by the posterior surface of the me-
dulla oblongata and pons. In the median line is seen the posterior median fissure;
it becomes gradually obliterated above, and terminates below in the point of the
calamus scriptorius, formed by the convergence of the posterior pyramids. At
this point is the orifice of a short canal termina;ting in a cul-de-sac, the remains of
the canal which extends in foetal life through the centre of the cord. On each
side of the median fissure are two slightly convex longitudinal eminences, the
fasciculi teretes; they extend the entire length of the floor, being indistinct below
and of a greyish colour, but well marked and whitish above. Each eminence con-
sists of fibres derived from the lateral tract and restiform body, which ascend to the
cerebrum. Opposite the crus cerebelli, on the outer side of the fasciculi teretes, is
a small eminence of dark grey substance, which presents a blueish tint through the
thin stratum covering it; this is called the locus cceruleus; and a thin streak of the
same colour continued up from this on either side of the fasciculi teretes, as far
as the top of the ventricle, is called the tcetiia violacea. The lower part of the
STRUCTURE OF CEREBELLUM.
473
floor of the ventricle is crossed by several white transverse lines, linece transversce;
they emerge from the posterior median fissure; some enter the crus cerebelli,
others enter the roots of origin of the auditory nerve, whilst some pass upwards
and outwards on the floor of the ventricle.
The Lining Membrane of the fourth ventricle is continuous with that of the
third, through the aqueduct of Sylvius, and its cavity communicates below with
the sub-arachnoid space of the brain and cord through an aperture in the layer of
pia mater extending between tlie cerebellum and medulla oblongata. Laterally,
this membrane is reflected outwards a short distance between the cerebellum and
medulla.
The Choroid Plexuses of the fourth ventricle are two in number; they are
delicate vascular fringes, which project into the ventricle on each side, passing
from the point of the inferior vermiform process to the outer margin of the resti-
form bodies.
The Grey Matter in the floor of the ventricle consists of a tolerably thick
stratum, continuous below with the grey commissure of the cord, and extending
up as high as the aqueduct of Sylvius, besides some special deposits connected
with the roots of origin of certain nerves. In the upper half of the ventricle is
a projection situated over the nucleus, from which the sixth and facial nerves
take a common origin. In the lower half are three eminences on each side for
the roots of origin of the eighth and ninth nerves.
Structure. If a vertical section is made through either hemisphere of the cere
bellum, midway between
its centre and the superior 2+9.— Vertical Section of the Cerebellum.
vermiform process; it will
be found to consist of a
central stem of white mat-
ter, which contains in its
interior a dentate body.
From the surface of each
hemisphere, a series of
plates of medullary matter
are detached, which, co-
vered with grey matter,
form the laminae; and from
its anterior part arise three
large processes or pedun-
cles, superior, middle, and
inferior, by which it is con-
nected with the rest of the
encephalon.
The Lamina are about
ten or twelve in number, including those on both surfaces of the organ, those
in front being detached at a right angle, and those behind at an acute angle; as
each lamina proceeds outwards, other secondary laminae are detached from it, and
from these tertiary laminae. The arrangement thus described gives to the cut
surface of the organ a foliated appearance, to which the name arbor vitcB has been
given. Each lamina consists of white matter, covered externally by a layer of
grey substance.
The white matter of each lamina is derived partly from the central stem; in
addition to which white fibres pass from one lamina to another.
The grey matter resembles somewhat the cortical substance of the convolu-
tions, consisting of two layers, the external one, soft and of a greyish colour, the
internal one, firmer and of a rust colour.
The Corpus Dentatum, or Ganglion of the Cerebellum, is situated a little to
the inner side of the centre of the stem of white matter. It consists of an open
bag or capsule of grey matter, the section of which presents a grey dentated out-
474
NEEVOUS SYSTEM.
line, being open at its anterior part. It is surrounded by white fibres; white
fibres are also contained in its interior, which issue from it to join the superior
peduncles.
The Peduncles of the cerebellum, superior, middle, and inferior, serve to con-
nect it with the rest of the encephalon.
The Superior Peduncles {Processus e Cerebello ad Testes) connect the cere-
bellum with the cerebrum; they pass forwards and upwards to the testes, beneath
which they ascend to the crura cerebri and optic thalami, forming part of the
diverging cerebral fibres: each peduncle forms part of the lateral boundary of the
fourth ventricle, and is connected with its fellow of the opposite side by the valve
of Vieussens. Behind, it is continuous with the folia of the inferior vermiform
process, and with the white fibres in the interior of the corpus dentatum. Beneath
the corpora quadrigemina, the innermost fibres of each peduncle decussate with
each other, so that some fibres from the right half of the cerebellum are continued
to the left half of the cerebrum.
The Inferior Peduncles {Processus ad Medullarn), connect the cerebellum with
the medulla oblongata. They pass downwards, to the back part of the medulla,
and form part of the restiform bodies. Above, the fibres of each process are con-
nected chiefly with the laminae, on the upper surface of the cerebellum; and below,
they are connected with all three tracts of the half of the medulla, and, through
these, with the corresponding half of the cord, excepting the postei'ior median
columns.
The Middle Peduncles {Processus ad Ponteni), the largest of the three, connect
together the two hemispheres of the cerebellum, forming their great transverse
commissure. They consist of a mass of curved fibres, which arise in the lateral
parts of the cerebellum, and pass across to the same points on the opposite side.
They form the transverse fibres of the pons Varolii.
Cranial Nerves.
THE Cranial Nerves, nine in number on each side, include all those which arise
from some part of the cerebro- spinal centre, and are transmitted through
foramina in the base of the cranium. They have been named numerically,
according to the order in which they pass out of this cavity. Their names are
also derived from the part to which each is distributed, or from the special
function appropriated to each. Taken in their order, from before backwards,
they are as follows:
1st. Olfactory. , j Facial (Portio dura).
2nd. Optic. ' ' I Auditory (Portio mollis).
3rd. Motores oculorum. ( Glosso-pharyngeal.
4th. Pathetic. 8th. J Pneumogastric, or Par vagum.
5th. Trifacial, Trigemini. ( Spinal accessory.
6th. Abducentes. 9th. Hypo-glossal.
The cranial nerves may be subdivided into three groups, according to the
peculiar function possessed by each, viz., nerves of special sense; nerves of
motion; and compound nerves, that is, the function of which is both motor and
sensitive. These groups may be thus arranged:
Nerves of Special Sense. Nerves of Motion.
1st. Olfactory. 3rd. Motores oculorum.
2nd. Optic. 4th. Pathetic.
7th. Auditory (Portio mollis). 6th. Abducentes.
7th. Facial (Portio dura).
9th. Hypo-glossal.
Compound Nerves.
5th. Trifacial.
{Glosso-pharyngeal.
Pneumogastric.
Spinal accessory.
All the cranial nerves are connected to some part of the surface of the brain.
This is termed their superficial, or apparent origin. But the fibres may, in all
cases, be traced deeply into the substance of the organ. This would form their
deep, or real origin.
Nerves of Special Sense.
The First, or Olfactory Nerve, the special nerve of the sense of smell, may
be regarded as a portion of the cerebral substance, pushed forward in direct
relation with the organ to which it is distributed. It arises by three roots.
The external, or long root, is a narrow, white, medullary band, which passes
outwards across the fissure of Sylvius, into the substance of the middle lobe of the
cerebrum. Its deep origin may be traced to the corpus striatum*, the superficial
fibres of the optic thalamus f, the anterior commissure |, and the convolutions of
the island of Reil.
The middle, or grey root, arises from a papilla of grey matter (caruncula
mammillaris), imbedded in the anterior lobe. This root is prolonged into the
nerve from the adjacent part of the brain, and contains white fibres in its interior,
which are connected with the corpus striatum. .
The internal, or short root, is composed of white fibres, which arise from the
* Vieussens, Winslow, Monro, Mayo. f Valentin. t Cruvelhier. >-
476
CRANIAL NERVES.
inner and back part of the anterior lobe, being connected, according to Foville,
with the longitudinal fibres of the gyrus fornicatus.
These three roots unite and form a flat band, narrower in the middle than at either
extremity, and its section of a somewhat prismoid form. It is of soft texture, and
contains a considerable amount of grey matter in its substance. As it passes for-
wards, it is contained in a deep sulcus, between two convolutions, lying on the
under surface of the anterior lobe, on either side of the longitudinal fissure, and is
retained in position by the arachnoid membrane which covers it. On reaching the
cribriform plate of the ethmoid bone, it expands into an oblong mass of greyish-
white substance, the olfactory bulb. From the under part of this bulb are given
off numerous filaments, about twenty in number, which pass through the cribriform
foramina, and are distributed to the mucous membrane of the nose. Each fila-
ment is surrounded by a tubular prolongation from the dura mater, and pia mater,
the former being lost on the periosteum lining the nose; the latter, in the neuri-
lemma of the nerve. The filaments, as they enter the nares, are divisible into
three groups, an inner group, larger than those on the outer wall, spread out over
the upper third of the septum; a middle set, confined to the roof of the nose; and
an outer set, which are distributed over the superior and middle turbinated bones,
and the surface of the ethmoid in front of them. As the filaments descend, they
unite in a plexiform network, and become gradually lost in the lining membrane.
Their mode of termination is unknown.
The olfactory differs in structure from other nerves, in containing grey matter
in its interior, being soft and pulpy in structure, and destitute of neurilemma. Its
filaments are deficient in the white substance of Schwann, are not divisible into
fibrillae, and resemble the gelatinous fibres in being nucleated, and of a finely-
granular texture.
Optic Nerve.
The Second, or Optic Nerve, the special nerve of the sense of sight, is
distributed exclusively to the eyeball. The nerves of opposite sides are con-
nected together at the commissure; and from
the back of the commissure they may be
traced to the brain, under the name of the
optic tracts.
The optic tract, at its connection with the
brain, divides into two bands which are con-
tinued into the optic thalami, the corpora
geniculata, and the corpora quadrigemina.
The fibres of origin from the thalamus may
be traced partly from its surface, and partly
from its interior. From this origin, the tract
winds obliquely across the under surface of
the crus cerebri, in the form of a flattened
band, destitute of neurilemma, and is attached
to it by its anterior margin. It now assumes
cylindrical form, and, as it passes forwards,
1 connected with the tuber cinereum, and la-
mina cinerea, from both of which it receives
fibres. According to Foville, it is also con-
nected with the taenia semicircularis, and the
anterior termination ot the gyrus fornicatus. It finally joins with the nerve of
the opposite side to form the optic commissure.
The commissure, somewhat quadrilateral in form, rests upon the olivary pro-
cess of the sphenoid bone, being bounded, in front, by the lamina cinerea; be-
hind, by the tuber cinereum; on either side, by the substantia perforata antica;
Within the commissure, the optic nerves of the two sides undergo a partial
decussation. The fibres which form the inner margin of each tract, are continued
across from one to the other side of the brain, and have no connection with the
250. — The Optic Nerves and Optic
Tracts.
OLFACTORY; OPTIC; AUDITORY. 477
optic nerves. These may be regarded as commissural fibres between the thalami
of opposite sides. Some fibres are continued across the anterior border of the
chiasma, and connect the optic nerves of the two sides, having no relation with
the optic tracts. They may be regarded as commissural fibres between the two
retinjB. The outer fibres of each tract are continued
into the optic nerve of the same side. The centi*al ^S'- — Course of the Fibres
fibres of each tract are continued into the optic nerve ^" ^^^*^ Optic Commiasure.
of the opposite side, decussating in the commissure
with similar fibres of the opposite tract.
The optic nerves arise from the fore part of the
commissure, and, diverging from one another, become
rounded in form, firm in texture, and are enclosed in
a sheath derived from the arachnoid. As each nerve
passes through the corresponding optic foramen, it receives a sheath from the
dura mater; and as it enters the orbit, this sheath subdivides into two layers, one
of which becomes continuous with the periosteum of the orbit; the other forms a
sheath for the nerve, and becomes lost in the sclerotic. The nerve passes through
the cavity of the orbit, pierces the sclerotic and choroid coats at the back part of
the eyeball, a little to the nasal side of its centre, and expands into the retina. A
small artery, the arteria centralis retinae, perforates the optic nerve a little behind
the globe, and runs along its interior in a tubular canal of fibrous tissue. It sup-
plies the internal surface of the retina, and is accompanied by corresponding veins.
Auditory Nerve.
The Auditory Nerve (portio mollis of the seventh pair), is the special nerve
of the sense of hearing, being distributed exclusively to the internal ear. The
hard portion of the seventh pair (portio dura), or facial nerve, is the motor nerve
of the face. It will be described with the motor cranial nerves.
The auditory nerve arises from numerous white stria3, the lineae transversae,
which emerge from the posterior median fissure in the anterior wall, or flooi', of
the fourth ventricle. It is also connected with the grey matter of the medulla,
which corresponds to the locus casruleus. According to Foville, the roots of this
nerve are connected, on the under surface of the middle peduncle, with the
grey substance of the cerebellum, with the flocculus, and with the grey matter at
the borders of the calamus scriptorius. The nerve winds round the restiform
body, from which it receives fibres, and passes forwards across the posterior
border of the crus cerebelli, in company with the facial nerve, from which it is
partially separated by a small artery. It then enters the meatus auditorius, in
company with the facial nerve, and, at the bottom of the meatus, divides into two
branches, cochlear and vestibular. The auditory nerve is very soft in texture,
(hence the name, portio mollis), destitute of neurilemma, and within the meatus,
receives one or two filaments from the facial.
The Motor Cranial Nerves.
The Third Nerve {Motor Oculi), is the chief motor nerve of the muscles of
the eyeball. It is a rather large nerve, of rounded form and firm texture, having
its apparent origin from the inner surface of the crus cerebri, immediately in
front of the pons Varolii.
The deep origin may be traced into the substance of the crus, where some of
its fibres are connected with the locus niger; others run downwards, among the
longitudinal fibres of the pons ; whilst others ascend, to be connected with the
tubercula quadrigemina, and valve of Vieussens. According to Stilling, the
fibres of the nerve pierce the peduncle and locus niger, and arise from a grey
nucleus in the floor of the aqueduct of Sylvius. On emerging from the brain, it
is invested in a sheath of pia mater, and enclosed in a prolongation from the
arachnoid. It then pierces the dura mater on the outer side of the anterior
clinoid process, where its serous covering is reflected from it, and passes along
the outer wall of the cavernous sinus, above the other orbital nerves, I'eceiving
in its course one or two filaments from the cavernous plexus of the sympathetic.
478
CRANIAL NERVES.
It then divides into two brandies, which enter the orbit through the sphenoidal
fissure, between the two
252, — Nerves of the Orbit. Seen from above.
]3tfra3jrachleoa*7r\
Recurrent Fllain^nt
( to J) II ra -Mater
heads of the External rec-
tus muscle. On passing
through this fissure, this
nerve is placed below the
fourth, and the frontal and
lachrymal branches of the
ophthalmic nerve.
The superior division,
the smaller, passes inwards
across the optic nerve, and
supplies the Superior rectus
and Levator palpebras.
The inferior division,
the larger, divides into
three branches. One passes
beneath the optic nerve to
the Internal rectus; another
to the Inferior rectus; and
the third, the largest of the
three, passes forwards be-
tween the Inferior and Ex-
ternal recti, to the Inferior
oblique. From the latter, a
short, thick branch is given
oflP to the lower part of the
lenticular ganglion, forming
its inferior root, as well as
two filaments to the Inferior
rectus. All these branches
enter the muscles on their
ocular surface.
Fourth Nerve.
The Fourth, or trochlear nerve, is the smallest of the cranial nerves. It
arises from the upper part of the valve of Vieussens, immediately behind the testis,
and divides beneath the corpora quadrigemina, into two fasciculi ; the anterior one
arising from a nucleus of grey matter, close to the middle line of the floor of the
Sylvian aqueduct; the posterior one from a grey nucleus, at the upper part of the
floor of the fourth ventricle, close to the origin of the fifth nerve. The two nerves
are connected together at their origin, by a transverse band of white fibres, which
crosses the surface of the velum. The nerve winds round the outer side of the
crus cerebri, immediately above the pons Varolii, pierces the dura mater in the
free border of the tentorium cerebelli, near the posterior clinoid process, above the
oval opening for the fifth nerve, and passes forwards through the outer wall of the
cavernous sinus, below the third; but, as it enters the orbit, through the sphe-
noidal fissure, it becomes the highest of all the nerves. In the orbit, it passes
inwards, above the origin of the Levator palpebrse, and finally enters the orbital
surface of the Superior oblique muscle.
In the outer wall of the cavernous sinus, this nerve receives some filaments
from the carotid plexus of the sympathetic. It is not unfrequently blended with
the ophthalmic division of the fifth; and occasionally gives off a branch to assist
in the formation of the lachrymal nerve. It also gives off a recurrent branch,
which passes backwards between the layers of the tentorium, dividing into two
or three filaments, which may be traced as far back as the wall of the lateral
sinus.
THIRD; FOURTH; SIXTH.
479
Sixth Nerve.
The Sixth Nerve (Abducens), takes its apparent origin by several filaments
from the constricted part of the corpus pyramidale, close to the pons, or from the
lower border of the pons itself.
The deep origin of this nerve has been traced, by Mayo, between the fasciculi
of the corpus pyramidale, to the posterior part of the medulla, where Stilling
has shown its connection with a grey nucleus in the floor of the fourth ventricle.
The nerve pierces the dura mater, immediately below the posterior clinoid pro-
cess, lying in a groove by the side of the body of the sphenoid bone. It passes
forwards through the cavernous sinus, lying on the outer side of the internal
carotid artery, where it is joined by several filaments from the carotid plexus, by
one from Meckel's ganglion (Bock), and another from the ophthalmic nerve. It
enters the orbit through the sphenoidal fissure, and lies above the ophthalmic
vein, from which it is separated by a lamina of dura mater. It then passes be-
tween the two heads of the External rectus, and is distributed to that muscle on
its ocular surface.
253. — Nerves of the Orbit and Ophthalmic Ganglion. Side view.
The above-mentioned nerves, as well as the ophthalmic division of the fifth, as
they pass to the orbit, bear a certain relation to each other in the cavernous
sinus, at the sphenoidal fissure, and in the cavity of the orbit, which will be now
described.
In the Cavernous Sinus, the third, fourth, and ophthalmic division of the fifth,
are placed in the dura mater, forming the outer wall of the sinus in numerical
order, both from above downwards, and from within outwards. The sixth nerve
lies at the outer side of the internal carotid artery. As these nerves pass forwards
to the sphenoidal fissure, the third and fifth nerves become divided: the sixth
approaches the rest; so that their relative position becomes considerably changed.
In the Sphenoidal Fissure, the fourth, and the frontal and lachrymal divisions
of the ophthalmic, lie upon the same plane, the former being most internal, the
latter external; and they enter the cavity of the orbit above the muscles. The
remaining nerves enter that cavity between the two heads of the External rectus.
The superior division of the third is the highest; beneath this, the nasal branch
of the fifth; then the inferior division of the third; and the sixth lowest of all.
In the Orbit, the fourth, and the frontal and lachrymal divisions of the ophthalmic,
lie on the same plane immediately beneath the periosteum, the fourth nerve being
internal and resting on the Superior oblique, the frontal resting on the Levator
480
CRANIAL NERVES.
palpebras, and the lachrymal on the External rectus. Next in order comes the
superior division of the third nerve lying immediately beneath the Superior rectus,
and then the nasal division of the fifth crossing the optic nerve from the outer to
the inner side of this cavity. Beneath these is found the optic nerve, surrounded
in front by the ciliary nerves, and having the lenticular ganglion on its outer
side, between it and the External rectus. Below the optic is the inferior division
of the third, and the sixth, which lies on the outer side of the cavity.
Facial Nerve.
The Facial Nerve, the hard portion of the seventh pair, is the motor nerve of
the face. It arises from the lateral tract of the medulla oblongata, in the groove
between the olivary and restiform bodies. Its deep origin may be traced to the
floor of the fourth ventricle, where it is connected with the same nucleus as the
sixth nerve. This nerve is situated a little nearer to the middle line than the
portio mollis, close to the lower border of the pons Varolii, from which some of
its fibres are derived.
Connected with this nerve, and lying between it and the portio mollis, is
a small fasciculus {portio inter duram et mollem of Wrisberg). This accessory
portion arises from the lateral column of the cord.
The nerve passes forwards and outwards upon the crus cerebelli, and enters the
internal auditory meatus with
254. — The Course and Connections of the Facial Nerve
in the Temporal Bone.
Sonalli Pcfrosnl
III I It Tnesac nlia, Gangirfovmls
lAudtfnry
the auditory nerve. Within
the meatus, the facial nerve
lies first to the inner side of,
and then in, a groove upon
the auditory, and is connected
to it by one or two filaments.
At the bottom of the mea-
tus, it enters the aqueductus
Fallopii, and follows the ser-
pentine course of that canal
through the petrous portion
of the temporal bone, from its commencement at the internal meatus to its termi-
ation at the stylo-mastoid foramen. It is at first directed outwards towards the
hiatus Fallopii, where it forms a reddish gangliform swelling (intumescentia gan-
glioformis), and is joined by several nerves; bending suddenly backwards, it runs in
the internal wall of the cavity of the tympanum, above the fenestra ovalis, and at
the back of this cavity passes vertically downwards to the stylo-mastoid foramen.
On emerging from this aperture, it runs forwards in the substance of the parotid
gland, crosses the external jugular vein and external carotid artery, and divides
behind the ramus of the lower jaw into two primary branches, temporo-facial and
cervico-facial, from which numerous ofiTsets are distributed over the side of the head,
face, and upper part of the neck, supplying the superficial muscles in this region.
The communications of the facial nerve may be thus arranged:
In the internal auditory meatus . With the auditory nerve.
With Meckel's ganglion by the large pe-
trosal nerve.
With the otic ganglion by the small pe-
trosal nerve.
With the sympathetic on the middle me-
ningeal by the external petrosal nerve.
With the pneumogastric.
„ glosso-pharyngeal.
„ carotid plexus.
„ auricularis magnus.
„ auriculo-temporal.
On the face .... With the three divisions of the fifth.
In the aqueductus Fallopii
At its exit from the stylo-mastoid
foramen . . . .
FACIAL. 481
In the internal auditory meatus, some minute filaments pass between the facial
and auditory nerves.
Opposite the hiatus Fallopii, the gangliform enlargement on the facial nerve
communicates, by means of the large superficial petrosal nerve, with Meckel's
ganglion; by a filament from the smaller superficial petrosal, with the otic gang-
lion; and by the external superficial petrosal, with the sympathetic filaments
accompanying the middle meningeal artery (Bidder). From the gangliform
enlargement, according to Arnold, a twig is sent back to the auditory nerve.
At its exit from the stylo-mastoid foramen, it sends a twig to the pneumogastric,
another to the glosso-pharyngeal nerve, and communicates with the carotid plexus
of the sympathetic, with the great auricular branch of the cervical plexus, with
the auriculo-temporal branch of the inferior maxillary nerve in the parotid gland,
and on the face with the tei'minal branches of the three divisions of the fifth.
Branches of Distribution.
Within aqueductus Fallopii i ^if 1 ^ '
( Chorda tympani.
A X _^'x D i 1 ^ • 1 ( Posterior auricular.
At e*it irom stylo-mastoid ] ^.
i-_„- '' \ Digastric.
I Stylo-hyoid.
{Temporal.
Malar.
Infra-orbital,
un tne lace . . .<, , c^
I oupra-maxillary.
Cervico-facial \ Infra-maxillary.
(. Cervical.
The Tympanic Branch is a small filament, which supplies the Stapedius muscle.
It arises from the nerve opposite the pyramid.
The Chorda Tympani is given off from the facial as it passes vertically down-
wards at the back of the tympanum, about a quarter of an inch before its exit
from the stylo-mastoid foramen. It ascends from below upwards in a distinct
canal, parallel with the aqueductus Fallopii, and enters the cavity of the tym-
panum through an opening between the base of the pyramid and the attachment
of the membrana tympani, and becomes invested with mucous membrane. It
passes forwards through the cavity of the tympanum, between the handle of the
malleus and vertical ramus of the incus, to its anterior inferior angle, and emerges
from that cavity through a distinct foramen at the inner side of the Glasserian
fissure. It then descends between the two Pterygoid muscles, and meets the
gustatory nerve at an acute angle; after communicating with this nerve, it
accompanies it to the submaxillary gland; it then joins the submaxillary ganglion,
and terminates in the Lingualis muscle.
The Posterior Auricular Nerve arises close to the stylo-mastoid foramen, and
passes upwards in front of the mastoid process, where it is joined by a filament
from the auricular branch of the pneumogastric, and communicates with the deep
branch of the auricularis magnus; as it ascends between the meatus and mastoid
process it divides into two branches. The auricular branch supplies the Retra-
hens aurem, and the integument at the back part of the auricle. The occipital
branch, the larger, passes backwards along the superior curved line of the occi-
pital bone, and supplies the occipital portion of the Occipito-frontalis and the
integument.
The Stylo-hyoid is a long slender branch, which passes inwards, entering the
Stylo-hyoid muscle about its middle; it communicates with the sympathetic fila-
ments on the external carotid artery.
The Digastric Branch usually arises by a common trunk with the preceding;
it divides into several filaments, which supply the posterior belly of the Digastric;
one of these perforates that muscle to join the glosso-pharyngeal nerve.
I I
482
CRANIAL NERVES.
The Temporo-facial, the larger of the two terminal branches, passes upwards
and forwards through the parotid gland, crosses the neck of the condyle of the
jaw, being connected in this situation with the auriculo-temporal branch of the
inferior maxillary nerve, and divides into branches, which are distributed over
the temple and upper part of the face; these may be divided into three sets, tem-
poral, malar, and infra-orbital.
The temporal branches cross the zygoma to the temporal region, supplying
the Attrahens aurem and the integument, and join with the temporal branch of
the superior maxillary, and with the auriculo-temporal branch of the inferior
maxillary. The more anterior branches supply the frontal portion of the Occipito-
255. — The Nerves of the Scalp, Face, and Side of the Neck.
Terminattons
ra-trochlear
■sf Infra -troMeur
if Nasal
frontalis, and the Orbicularis palpebrarum muscle, joining with the supra-orbital
branch of the ophthalmic.
The malar branches pass across the malar bone to the outer angle of the orbit,
where they supply the Orbicularis and Corrugator supercilii muscles, joining with
filaments from the lachrymal and supra-orbital nerves: others supply the lower
eyelid, joining with filaments of the malar branches of the superior maxillary
nerve.
The mfra-orbital, of larger size than the rest, pass horizontally forwards to
NINTH, OR HYPO-GLOSSAL. 483
be distributed between the lower margin of the orbit and the mouth. The super-
ficial branches run beneath the skin and above the superficial muscles of the
face, which they supply, being distributed to the integument and hair follicles;
some supply the lower eyelid and Pyramidalis nasi, joining, at the inner angle
of the orbit, with the infra-trochlear and nasal branches of the ophthalmic.
The deep branches pass beneath the Levator labii superioris, supply it and the
Levator anguli oris, and form a plexus (infra-orbital) by joining with the infra-
orbital branch of the superior maxillary nerve.
The Cervico-facial, the other division of the facial nerve, passes obliquely
downwards and forwards through the parotid gland, where it is joined by branches
from the great auricular nerve; opposite the angle of the lower jaw it divides into
branches, which are distributed on the lower half of the face and upper part of
the neck. These may be divided into three sets, buccal, supra-maxillary, and
infra-maxillary.
The buccal branches cross the Masseter muscle, join the infra-orbital branches
of the cervico-facial division of the nerve, and with filaments of the buccal branch
of the inferior maxillary nerve. They supply the Buccinator and Orbicularis
oris.
The supra-maxillary branches pass forwards beneath the Platysma and De-
pressor anguli oris, supplying the muscles and the integument of the lip and chin,
anastomosing with the mental branch of the inferior dental nerve.
The infra-maxillary branches run forward beneath the Platysma, and form a
series of arches across the side of the neck over the supra-hyoid region. One of
these branches descends vertically to join with the superficial cervical nerve
from the cervical plexus; others supply the Platysma and Levator labii supe-
rioris.
Ninth, oe Hypo-glossal Nerve.
The Ninth Nerve {Hypo- glossal) is the motor nerve of the tongue. It arises
by several filaments, from ten to fifteen in number, from the groove between the
pyramidal and olivary bodies, in a continuous line with the anterior roots of the
spinal nerves. According to Stilling, these roots may be traced to a grey nucleus
in the floor of the medulla oblongata, between the posterior median furrow and
the nuclei of the glosso-pharyngeal and vagus nerves. The filaments of this
nerve are collected into two bundles, which perforate the dura mater separately,
opposite the anterior condyloid foramen, and unite together after their passage
through it. The nerve descends almost vertically downwards to a point corre-
sponding with the angle of the jaw. It is at first deeply seated beneath the
internal carotid and jugular vein, and intimately connected with the pneumogastric
nerve; it then passes forwards between the vein and artery, and descending the
neck, becomes superficial below the Digastric muscle. The nerve then loops
round the occipital artery, and crosses the external carotid below the tendon of
the Digastric muscle. It passes beneath the Mylo-hyoid muscle, lying between it
and the Hyo-glossus, and is connected at the anterior border of the latter muscle
with the gustatory nerve; it is then continued forwards into the Genio-hyo-glossus
muscle as far as the tip of the tongue, distributing branches to its substance.
The communicating branches of this nerve are with the
Pneumogastric. First and second cervical nerves.
Sympathetic. Gustatory.
The communication with the pneumogastric takes place close to the exit of the
nerve from the skull, numerous filaments passing between the Hypo-glossal and
second ganglion of the pneumogastric, or both being united so as to form one
mass.
It communicates with the sympathetic opposite the atlas, by branches derived
from the superior cervical ganglion, and in the same situation it is jomed by a
filament with the loop connecting the two first cervical nerves.
I I 2
484
CRANIAL NERVES.
The communication with the gustatory takes place near the anterior border of
the Hyo-glossus muscle by numerous filaments, which ascend upon it.
The branches of distribution are the
Descendens noni. Thyro-hyoid.
Muscular.
The Descendens Noni is a long slender branch, which quits the hypo-glossal
where it turns round the occipital artery. It descends obliquely across the sheath
of the carotid vessels, and joins just below the middle of the neck, to form a loop
256. — Hypo-glossal Nerve, Cervical Plexus, and their Branches.
with the communicating branches from the second and third cervical nerves. From
the convexity of this loop, branches pass foi'wards to supply the Sterno-hyoid,
Sterno-thyroid, and both bellies of the Omo-hyoid. According to Arnold, another
filament descends in front of the vessels into the chest, which joins the cardiac
and phrenic nerves. The descendens noni is occasionally contained in the sheath
of the carotid vessels, being sometimes placed over and sometimes beneath the
internal jugular vein.
The Thyro-hyoid is a small branch, arising from the hypo-glossal near the pos-
terior border of the Hyo-glossvis; it passes obliquely across the great cornu of the
hyoid bone, and supplies the Thyro-hyoid muscle.
The diuscular Branches are distributed to the Stylo-glossus, Hyo-glossus,
FIFTH NERVE. 485
Genio-liyoid, and Genio-hyo-glossus muscles. At tlic under surface of the tongue,
numerous slender branches pass upwards into the substance of the organ.
Compound Cranial Nkrves.
The Fifth Nerve {Trifacial, Trigeminus) is the largest cranial nerve, and is
somewhat analogous to a spinal nerve, in its origin by two roots, and in the
existence of a ganglion on its posterior root. The functions of this nerve are
various. It is a nerve of special sense, of common sensation, and of motion. It is the
nerve of the special sense of taste, the great sensitive nerve of the head and face, and
the motor nerve of the muscles of mastication. It arises by two roots, a posterior
larger or sensory, and an anterior smaller or motor root. Its superficial origin is
from the side of the pons Varolii, a little nearer to its upper than its lower
border. The smaller root consists of three or four bundles; in the larger, the
bundles are more numerous, varying in number from seventy to a hundred: the
two roots are separated from one another by a few of the transverse fibres of the
pons. The deep origin of the larger, or sensory root, may be traced between the
transverse fibres of the pons Varolii to the lateral tract of the medulla oblongata,
immediately behind the olivary body. According to some anatomists, it is con-
nected with the grey nucleus at the back part of the medulla, between the fasciculi
teretes and restiform columns. By others, it is said to be continuous with the
fasciculi teretes and lateral column of the cord; and, according to Foville, some
of its fibres are connected with the transverse fibres of the pons; whilst others
enter the cerebellum, spreading out on the surface of its middle peduncle. The
motor root has been traced by Bell and Retzius to be connected with the pyra-
midal body. The two roots of the nerve pass forwards through an oval opening
in the dura mater, at the apex of the petrous portion of the temporal bone:
here the fibres of the larger root enter a large semilunar ganglion (Gasserian),
while the smaller root passes beneath it without having any connection with it,
and joins outside the cranium with one of the trunks derived from it.
The Gasserian, or Semilunar Ganglion, is lodged in a depression near the
apex of the petrous portion of the temporal bone. It is of a somewhat crescentic
form, with its convexity turned forwards. Its upper surface is intimately adherent
to the dura mater.
Branches. This ganglion receives, on its inner side, filaments from the carotid
plexus of the sympathetic; and from it some minute branches are given off to the
tentorium cerebelli, and the dura mater, in the middle fossa of the cranium.
From its anterior border, which is directed forwards and outwards, three large
branches proceed, the ophthalmic, superior maxillary, and inferior maxillary.
The two first divisions of this nerve consist exclusively of fibres derived from the
larger root and ganglion, and are solely nerves of common sensation. The third,
or inferior maxillary, is composed of fibres from both roots. This, therefore,
strictly speaking, is the only portion of the fifth nerve which is compound, and
which can be said to bear analogy with a spinal nerve.
The Ophthalmic, or first division of the fifth, is a sensory nerve. It supplies
the eyeball, the lachrymal gland, the mucous lining of the eye and nose, and the
integument and muscles of the eyebrow and forehead (fig. 252). It is the smallest
of the three divisions of the fifth, arising from the upper part of the Gasserian
ganglion. It is a short, flattened band, about an inch in length, which passes for-
wards along the outer wall of the cavernous sinus, below the other nerves, and
just before entering the oi-bit, through the sphenoidal fissure, divides into three
branches, frontal, lachrymal, and nasal. The ophthalmic nerve is joined by fila-
ments from the cavernous plexus of the sympathetic, and gives off recurrent
filaments which pass between the layers of the tentorium, with a branch from the
fourth nerve.
Its branches are, the
Lachrymal. Frontal. Nasal.
486 CRANIAL XERYES.
The Lachrymal is the smallest of the three branches of the ophthalmic. Not
unfrequentlv, it arises by two filaments, one from the ophthalmic, the other from
the fourth, and this. Swan considers as the usual condition. It passes forwards
in a separate tube of dura mater, and enters the orbit through the narrowest part
of the sphenoidal fissure. In this cavity, it runs along the tipper border of the
External rectus muscle, with the lachrymal artery, and is connected with the orbital
branch of the superior maxillary nerve. Within the lachrymal gland it gives off
several filaments, which supply it and the conjunctiva. Finally, it pierces the
palpebral ligament, and terminates in the integument of the upper eyelid, joining
with filaments of the facial nerve.
The Frontal (fig. 252"), is the largest division of the ophthalmic, and may be
regarded, both from its size and direction, as the continuation of this nerve. It
enters the orbit above the muscles, through the highest and broadest part of the
sphenoidal fissure, and runs forwards along the middle line, between the Levator
palpebra; and the periostetun. Midway between the apex and base of this cavity,
it divides into vxo branches, supra- trochlear and supra-orbital.
The supra-trocJilear branch, the smaller of the two, passes inwards, above
the pulley of the Sttperior oblique muscle, and gives off a descending filament,
Avhich joins with the infra-trochlear branch of the nasal nerve. It then escapes
from the orbit between the pulley of the Superior oblique and the supra-orbital
foramen, curves up on to the forehead close to the bone, and ascends behind the
Corrugator supercilii, and Occipito-frontalis muscles, to both of which it is distri-
buted. Finally, it is lost in the integument of the forehead.
The supra-orbital branch passes forwards through the supra-orbital foramen,
and gives ofi". in this situation, palpebral filaments to the upper eyelid. It then
ascends upon the forehead, and terminates in muscular, cutaneous, and pericranial
branches. The muscular branches supply the Corrugator supercilii, Occipito-
frontalis, and Orbicularis palpebrarum, joining in the substance of the latter
muscle with the facial nerve. The cutaneous brandies, tn'o in number, an inner
and an outer, supply the integument of the cranium as far back as the occiput.
They are at first situated beneath the Occipito-frontalis. the former perforating
the frontal portion of the muscle, the latter its tendinous aponeurosis. The
pericranial branches are distributed to the pericranium, over the frontal and
parietal bones. They are derived from the ctitaneous branches whilst beneath the
muscle.
The y^asal 2\^erve, is intermediate in size between the frontal and lachrymal,
and more deeply placed than the other branches of the ophthalmic. It enters the
orbit between the two heads of the External rectus, passes obliquely inwards
across the optic nerve, beneath the Levator palpebree and Superior rectus muscles,
to the inner wall of this cavity, where it enters the anterior ethmoidal foramen,
immediately below the Superior oblique. It now enters the cavity of the cranium,
fraverses a shallow groove on the front of the cribriform plate of the ethmoid
bone, and passes down, through the slit by the side of the crista galli, into the
nose, where it divides into two branches, an internal and an external. The
internal branch supplies the mucous membrane near the fore part of the septum
of the nose. The external branch descends in a groove on the inner surface of
the nasal bone, and supplies a few filaments to the mucous membrane covering the
front part of the outer wall of the nares as far as the inferior spongy bone; it
then leaves the cavity of the nose, between the lower border of the nasal bone and
the upper lateral cartilage of the nose, and, passing down beneath the Com-
pressor nasi, supplies the integimient of the ala and tip of the nose, joiniug with
the facial nerve.
The branches of the nasal nerve are, the ganglionic, ciliary, and infra-
trochlear.
The ganglionic is a long, slender branch, about half an inch in length, which
itsually arises from the nasal, between the two heads of the External rectus. It
passes forwards on the outer side of the optic nerve, and enters the superior and
CILIARY GANGLION. 487
posterior angle of the ciliary ganglion, forming its superior, or long root. It is
sometimes joined by a filament from the cavernous plexus of the sympathetic, or
from the superior division of the third nerve.
The long ciliary nerves, two or three in number, are given off from the
nasal as it crosses the optic nerve. They join the short ciliary nerves from the
ciliary ganglion, pierce the posterior part of the sclerotic, and, running forwards
between it and the choroid, are distributed to the Ciliary muscle and iris.
The infra-trochlear branch is given off just as the nasal nerve passes
through the anterior ethmoidal foramen. It runs forwards alono- the upper
border of the Internal rectus, and is joined, beneath the pulley of the Superior
oblique, by a filament from the supra-trochlear nerve. It then passes to the
inner angle of the eye, and supplies the Orbicularis palpebrarum, the integument
of the eyelids, and side of the nose, the conjunctiva, lachrymal sac, and caruncula
lachrymalis.
Ga^'Glia of the Fifth Nerve.
Connected with the three divisions of the fifth nerve are four small ganglia,
which form the whole of the cephalic portion of the sympathetic. With the first
division is connected the ophthalmic ganglion; with the second division, the spheno-
palatine or Meckel's ganglion; and with the third, the otic and sub-maxillary gan-
glia. These ganglia receive sensitive filaments from the fifth, and motor filaments
from other sources; these filaments are called the roots of the ganglia. They are
also connected with each other, and with the cervical portion of the sympathetic.
The OPHTHAiiiic, Lenticular, or Ciliary Ga2s'Gliox (fig-253), is a small
quadrangular flattened ganglion, of a reddish-grey colour, and about the size of
a pin's head, situated at the back part of the orbit between the optic nerve and
the External rectus muscle, generally lying on the outer side of the ophthalmic
artery. It is enclosed in a quantity of loose fat, which makes its dissection some-
what difiicult.
Its branches of communication, or its roots, are three, all of which enter its
posterior border. One, the long root, is derived from the nasal branch of the
ophthalmic, and joins its superior angle. Another branch, the short root, is a
short thick nerve, occasionally divided into two parts; it is derived from that
branch of the third nerve which supplies the Inferior oblique muscle, and is con-
nected with the inferior angle of the ganglion. A third branch, the sympathetic
root, is a slender filament from the cavernous plexus of the sympathetic. This is
occasionally blended with the long root, and sometimes passes to the ganglion
by itself. According to Tiedemann, this ganglion receives a filament of commu-
nication from the spheno-palatine ganglion.
Its branches of distribution are the short ciliary nerves. These consist of from
ten to twelve delicate filaments, which arise from the fore part of the gangKon in
two bundles, connected with its superior and inferior angles; the upper bundle
consisting of four filaments, and the lower of six or seven. They run forwards
with the ciliary arteries in a wavy course, one set above and the other below the
optic nerve, pierce the sclerotic at the back part of the globe, pass forwards in
delicate grooves on its inner surface, and are disfributed to the ciliary muscle and
iris. A small filament is described by Tiedemann, penetrating the optic nerve
with the arteria centralis retinae.
Superior Maxillary Ner^st: (fig. 257).
The superior maxillary, or second division of the fifth, is a sensory nerve. It
is intermediate, both in position and size, between the ophthalmic and inferior
maxillary. It commences at the middle of the Gasserian ganglion as a flattened
plexiform band, passes forwards through the foramen rotundum, where it becomes
more cylindrical in form and firmer in texture. It then crosses the spheno-
maxillary fossa, traverses the infra-orbital canal in the floor of the orbit, emerging
upon the face at the infra-orbital foramen. At its termination, the nerve lies
488
CRANIAL NERVES.
beneath the Levator labii superioris muscle, and divides into a leash of branches,
which spread out upon the side of the nose, the lower eyelid, and upper lip, join-
ing with filaments of the facial nerve.
2 5 7. —Distribution of the Second and Third Divisions of the Fifth Nerve
and Sub-maxillary Ganglion.
The branches of this nerve may be divided into three groups: I. Those given
off in the spheno-maxillai-y fossa. 2. Those in the infra-orbital canal. 3. Those
on the face.
[ Orbital.
Spheno-maxillary fossa ■'. Spheno-palatine.
i Posterior dental.
Anterior dental.
Infra- orbital canal
On the face
{Palpebral.
Nasal.
Labial.
The Orbital Branch arises in the spheno-maxillary fossa, enters the orbit by
the spheno-maxillary fissure, and divides into two branches, temporal and malar.
The temporal branch runs in a groove along the outer wall of the orbit (in
the malar bone), receives a branch of communication from the lachrymal, and
passing through a foramen in the malar bone, enters the temporal fossa. It
ascends between the bone and substance of the Temporal muscle, pierces this
SPHENO-PALATINE GANGLION. 489
muscle and the temporal fascia about an inch above the zygoma, and is distributed
to the integument covering the temple and side of the forehead, communicating
with the facial and auriculo- temporal branch of the inferior maxillary nerve.
The malar branch passes along the external inferior angle of the orbit, emerges
upon the face through a foramen in the malar bone, and perforating the Orbi-
cularis palpebrarum muscle on the prominence of the cheek, joins w^ith the
facial.
The SpJieno-palatine Branches, two in number, descend to the spheno-palatine
ganglion.
The Posterior Dental Branches arise from the trunk of the nerve just as it is
about to enter the infra-orbital canal; they are two in number, posterior and
anterior.
The posterior branch passes from behind forwards in the substance of the
superior maxillary bone, and joins opposite the canine fossa with the ante-
rior dental. Numerous filaments are given off from the lower border of this
nerve, which form a minute plexus in the outer wall of the superior maxillary
bone immediately above the alveolus. From this plexus, filaments are distributed
to the pulps of the molar and bicuspid teeth, the lining membrane of the antrum,
and corresponding portion of the gums.
The anterior branch is distributed to the gums and Buccinator muscle.
The Anterior Dental, of large size, is given oif from the superior maxillary
nerve just before its exit from the infra-orbital foramen; it enters a special canal
in the anterior wall of the antrum, and anastomoses with the posterior dental.
From this branch filaments are distributed to the incisor, canine, and first bicuspid
teeth; others are lost upon the lining membrane covering the front part of the
inferior meatus.
The Palpebral Branches pass upwards beneath the Orbicularis palpebrarum.
They supply this muscle, the integument, and conjunctiva of the lower eyelid,
joining at the outer angle of the orbit with the facial nerve and malar branch of
the orbital.
The Nasal Branches pass inwards; they supply the muscles and integument of
the side of the nose, and join with the nasal branch of the ophthalmic.
The Labial Branches, the largest and most numerous, descend beneath the
Levator labii superioris, and are distributed to the integument and muscles of the
upper lip, the mucous membrane of the mouth, and labial glands.
All these branches are joined, immediately beneath the orbit, by filaments from
the facial nerve, forming an intricate plexus, the infra-orbital.
Spheno-Palatine Ganglion.
The Spheno-Palatine Ganglion (Meckel's) (fig. 258), the largest of the cranial
ganglia, is deeply placed in the spheno-maxillary fossa, close to the spheno-
palatine foramen. It is triangular, or heart-shaped in form, of a reddish-grey
colour, and placed mainly behind the palatine branches of the superior maxillary
nerve, at the point where the sympathetic root joins the ganglion. It conse-
quently does not involve those nerves which pass to the palate and nose. Like
other ganglia, it possesses a motor, a sensory, and a sympathetic root. Its motor
root is derived from the facial, through the Vidian; its sensory root from the
fifth; and its sympathetic root from the carotid plexus, through the Vidian. Its
branches are divisible into four groups: ascending, which pass to the orbit; descend-
ing, to the palate; internal, to the nose; and posterior branches to the pharynx.
The Ascendi7ig Branches are two or three delicate filaments, which enter the
orbit by the spheno-maxillary fissure, and supply the periosteum. Arnold
describes and delineates these branches as ascending to the optic nerve; one, to
the sixth nerve (Bock); and one, to the ophthalmic ganglion (Tiedemann).
The Desceiiding or Palatine Branches are distributed to the roof of the
mouth, the soft palate, tonsil, and lining membrane of the nose. They are almost
490
CRANIAL NERVES.
a dii'ect continuation of the splieno-palatine branches of the superior maxillary
nerve, and are three in number, anterior, middle, and posterior.
The anterior, or large palatine nerve, descends through the posterior palatine
canal, emerges upon the hard palate, at the posterior palatine foramen, and passes
forwards through a groove in the hard palate, extending nearly to the incisor teeth.
258. — The Spheno-Palatine Ganglion and its Branches.
It supplies the gums, the mucous membrane and glands of the hard palate, and com-
municates in front with the termination of the naso-palatine nerve. While in the
posterior palatine canal, it gives off inferior nasal branches, which enter the nose
through openings in the palate-bone, and ramify over the middle meatus, and the
middle and inferior spongy bones; and, at its exit from the canal, a palatine
branch is distributed to both surfaces of the soft palate.
The middle, or external palatine nerve, descends in the same canal as the pre-
ceding, to the posterior palatine foramen, distributing branches to the uvula,
tonsil, and soft palate. It is occasionally wanting.
The posterior, or small palatine nerve, descends with a small artery through
the small posterior palatine canal, emerging by a separate opening behind the
posterior palatine foramen. It supplies the Levator palati muscle, the soft palate,
tonsil, and uvula.
The Internal Branches are distributed to the septum, and outer wall of the
nasal fossse. They are the superior nasal (anterior), and the naso-palatine.
The superior nasal branches (anterior), four or five in number, enter the
back part of the nasal fossa by the spheno-palatine foramen. They supply the
mucous membrane, covering the superior and middle spongy bones, and that lining
the posterior ethmoidal cells, a few being prolonged to the upper and back part of
the septum.
The naso-palatine nerve (Cotunnius), enters the nasal fossa with the other nasal
nerves, and passes inwards across the roof of the nose, below the orifice of the
sphenoidal sinus, to reach the septum; and then obliquely downwards and forwards
along its lower part, lying between the periosteum and pituitary membrane, to the
anterior palatine foramen. It descends to the roof of the mouth by a distinct
INFERIOR MAXILLARY NERVE.
491
canal, which opens below in the anterior palatine fossa; the right nerve, also in a
separate canal, being posterior to the left one. In the mouth, they become united,
supply the mucous membrane behind the incisor teeth, joining with the ante-
rior palatine nerve. It occasionally furnishes a few small filaments to the mucous
membrane of the septum.
The Posterior Branches are the Vidian and pharyngeal (ptery go- palatine).
The Vidian arises from the back part of the spheno-palatine ganglion, passes
through the Vidian canal, enters the cartilage filling in the foramen lacerum
basis cranii, and divides into two branches, the superficial petrosal, and the
carotid. In its course along the Vidian canal, it distributes a few filaments
to the lining membrane at the back part of the roof of the nose and septum,
and that covering the end of the Eustachian tube. These are upper posterior
nasal branches.
The petrosal branch {nervus petrosus siiperjlcialis major), enters the cranium
through the foramen lacerum basis cranii, having pierced the cartilaginous sub-
stance, filling in this aperture. It runs beneath the Gasserian ganglion and dura
mater, contained in a groove in the anterior surface of the petrous portion of the
temporal bone, enters the hiatus Fallopii, and, being continued through it, into the
aqueductus Fallopii, joins the gangliform enlargement on the facial nerve. Pro-
perly speaking, this nerve passes from the facial to the spheno-palatine ganglion,
forming its motor root.
The carotid branch is shorter, but larger than the petrosal, of a reddish-grey
colour, and soft in texture. It crosses the foramen lacerum, surrounded by the
cartilaginous substance which fills in that aperture, and enters the carotid canal, on
the outer side of the carotid artery, to join the carotid plexus.
The Pharyngeal Nerve {jptery go-palatine), is a small branch arising from the
back part of the ganglion, occasionally springing from the Vidian nerve. It
passes through the pterygo-palatine canal with the pterygo-palatine artery, and
is distributed to the lining membrane of the pharynx, behind the Eustachian
tube.
Inferior Maxillary Nerve.
The Inferior Maxillary Nerve distributes branches to the teeth and gums of
the lower jaw, the integument of the temple and external ear, lower part of the
face and lower lip, and the muscles of mastication: it also supplies the tongue
with its special nerve of the sense of taste. It is the largest of the three divisions
of the fifth, and consists of two portions, the larger, or sensory root, proceeding
from the inferior angle of the Gasserian ganglion ; and the smaller, or motor root,
which passes beneath the ganglion, and unites Avith the inferior maxillary nerve,
just after its exit through the foramen ovale. Immediately beneath the base of
the skull, this nerve divides into two trunks, anterior and posterior.
The anterior, and smaller division, which receives nearly the whole of the
motor root, divides into five branches, which supply the muscles of mastication.
They are the masseteric, deep temporal, buccal, and pterygoid.
The Masseteric Branch passes outwards, above the External pterygoid muscle,
in front of the temporo-maxillary articulation, and crosses the sigmoid notch, with
the masseteric artery, to the Masseter muscle, in which it ramifies nearly as far
as its anterior border. It occasionally gives a branch to the Temporal muscle, and
a filament to the articulation of the jaw.
The Deep Temporal Branches, two in number, anterior and posterior, supply
the deep surface of the Temporal muscle. The posterior branch, of small size,
is placed at the back of the temporal fossa. It is sometimes joined with the
masseteric branch. The anterior branch is reflected upwards, at the pterygoid
ridge of the sphenoid, to the front of the temporal fossa. It is occasionally
joined with the buccal nerve.
The Buccal Branch pierces the External pterygoid, and passes downwards be-
neath the inner surface of the coronoid process of the lower jaw, or through the
492 CRANIAL NERVES.
fibres of the Temporal muscle to reach the surface of the Buccinator, upon which
it divides into a superior and an inferior branch. It gives a branch to the External
pterygoid during its passage through this muscle, and a few ascending filaments to
the Temporal muscle, one of which occasionally joins with the anterior branch of the
deep temporal nerve. The upper branch supplies the integument and upper
part of the Buccinator muscle, joining with the facial nerve around the facial
vein. The lower branch passes forwards to the angle of the mouth; supplies
the integument and Buccinator muscle, as well as the mucous membrane lining
its inner surface, joining with the facial nerve.
The Pterygoid Branches are two in number, one for each Pterygoid muscle.
The branch to the Internal pterygoid is long and slender, and passes inwards to
enter the deep surface of the muscle. This nerve is intimately connected at its
origin with the otic ganglion. The branch to the External pterygoid is most
frequently derived from the buccal, but it may be given off* separately from the
anterior trunk of the nerve.
The posterior and larger division of the inferior maxillary nerve also receives
a few filaments from the motor root. It divides into three branches, auriculo-
temporal, gustatory, and inferior dental.
The AuRicuLO-TEMPORAL Nerve generally arises by two roots, between which
passes the middle meningeal artery. It passes backwards beneath the External
pterygoid muscle to the inner side of the articulation of the lower jaw. It then
turns upwards with the temporal artery, between the external ear and condyle of
the jaw, under cover of the parotid gland, and escaping from beneath this struc-
ture, divides into two temporal branches. The posterior temporal, the smaller of
the two, supplies the Attrahens aurem muscle, and is distributed to the upper
part of the pinna and the neighbouring integument. The anterior temporal
accompanies the temporal artery to the vertex of the skull, and supplies the
integument of the temporal region, communicating with the facial nerve.
The auriculo-temporal nerve has branches of communication with the facial
and otic ganglion. Those joining the facial nerve, usually two in number, pass
forwards behind the neck of the condyle of the jaw, and join this nerve at the
posterior border of the Masseter muscle. They form one of the principal branches
of communication between the facial and the fifth nerve. The filaments of com-
munication with the otic ganglion are derived from the commencement of the
auriculo-temporal nerve.
The Auricular Branches are two in number, inferior and superior. The infe-
rior auricular arises behind the articulation of the jaw, and is distributed to the
ear below the external meatus; other filaments twine around the internal maxil-
lary artery, and communicate with the sympathetic. The superior auricular
arises in front of the internal ear, and supplies the integument covering the tragus
and pinna.
Branches to the Meatus Auditorius, two in number, arise from the point of
communication between the temporo-auricular and facial nerves, and are distri-
buted to the meatus.
The Branch to the Temporo-maxillary Articulation is usually derived from
the auriculo-temporal nerve.
The Parotid Branches supply the parotid gland.
The Gustatory or Lingual Nerve (fig. 257), the special nerve of the sense of
taste, supplies the papillae and mucous membrane of the tongue. It is deeply
placed throughout the whole of its course. It lies at first beneath the External
pterygoid muscle, together with the inferior dental nerve, being placed to the
inner side of the latter nerve, and is occasionally joined to it by a branch which
crosses the internal maxillary artery. The chorda tympani also joins it at an acute
angle in this situation. The nerve then passes between the Internal pterygoid
muscle and the inner side of the ramus of the jaw, and crosses obliquely to the
side of the tongue over the Superior constrictor muscle of the pharynx, and be-
tween the Stylo-glossus muscle and deep part of the sub-maxillary gland; the
OTIC GANGLION.
493
nerve lastly runs .icross Wharton's duct, and along the side of the tongue to its
apex, being covered by the mucous membrane of the mouth.
Its branches of communication are with the sub-maxillary ganglion and hypo-
glossal nerve. The branches to the sub-maxillary ganglion are two or three in
number; those connected with the hypo-glossal nerve form a plexus at the anterior
margin of the hyo-glossus muscle.
Its branches of distribution are few in number. They supply the mucous
membrane of the mouth, the gums, the sub-lingual gland, and the conical and
fungiform papillaj and mucous membrane of the tongue, the terminal filaments
anastomosing at the tip of this organ with the hypo-glossal nerve.
The Inferior Dental is the largest of the three branches of the inferior max-
illary nerve. It passes downwards with the inferior dental artery, at first beneath
the External pteiygoid muscle, and then between the internal lateral ligament and
the ramus of the jaw to the dental foramen. It then passes forwards in the dental
canal in the inferior maxillary bone, lying beneath the teeth, as far as the mental
foramen, where it divides into two terminal branches, incisor and mental. The
incisor branch is continued onwards within the bone to the middle line, and sup-
plies the canine and incisor teeth. The mental branch emerges from the bone at
the mental foramen, and divides beneath the Depressor anguli oris into an external
branch, which supplies this muscle, the Orbicularis oris, and the integument, com-
municating with the facial nerve; and an inner branch, which ascends to the
lower lip beneath the Quadratus menti; it supplies this muscle and the mucous
membrane and integument of the lip, communicating with the facial nerve.
The branches of the inferior dental are the mylo-hyoid and dental.
The Mylo-hyoid is derived from the inferior dental just as that nerve is about
to enter the dental foramen. It descends in a groove on the inner surface of the
ramus of the jaw, in which it is retained by a process of fibrous membrane. It
supplies the cutaneous surface of the Mylo-hyoid muscle, and the anterior belly of
the Digastric, occasionally sending one or two filaments to the sub-maxillary
gland.
The Dental Branches supply the molar and bicuspid teeth. They correspond
in number to the fangs of those teeth; each nerve entering the orifice at the
point of the fang, and supplying the pulp of the tooth.
Two small ganglia are connected with, the inferior maxillary nerve: the otic,
with the trunk of the nerve; and the submaxillary, with its lingual branch, the
gustatory.
Otic Ganglion.
The Otic Ganglion (Arnold's) (fig. 259), is a small oval-shaped, flattened ganglion,
of a reddish-grey colour, situated immediately below the foramen ovale, on the inner
surface of the inferior maxillary nerve, and around the origin of the internal
pterygoid nerve. It is in relation, externally, with the trunk of the inferior
maxillary nerve, at the point where the motor root joins the sensory portion;
internally, with the, cartilaginous part of the Eustachian tube, and the origin of
the Tensor palati muscle; behind it, is the middle meningeal artery.
Branches of Communication. This ganglion is connected with the inferior
maxillary nerve, and its internal pterygoid branch, by two or three short, delicate
filaments, and also with the auriculo-temporal nerve: from the former, it obtains
its motor, from the latter its sensory root; its communication with the sympa-
thetic being effected by a filament from the plexus surrounding the middle
meningeal artery. This ganglion also communicates with the glosso-pharyngeal
and facial nerves, through the small petrosal nerve continued from the tympanic
plexus.
Its Branches of Distribution are a filament to the tensor tympani, and one to
the tensor palati. The former passes backwards, on the outer side of the
Eustachian tube; the latter arises from the ganglion, near the origin of the
internal pterygoid nerve, and passes forwards.
494
CRANIAL NERVES.
Submaxillary Ganglion.
The Submaxillary Ganglion {Q.g.2^j), is of small size, circular in form, and
situated above the deep portion of the submaxillary gland, near the posterior
border of the Mylo-hyoid muscle, being connected by filaments with the lower
border of the gustatory nerve.
259. — The Otic Ganglion and its Branches
Branches of Communication. This ganglion is connected with the gustatory
nerve by a few filaments which join it separately, at its fore and back part. It
also receives a branch from the chorda tympani, by which it communicates with
the facial; and communicates with the sympathetic by filaments from the nervi
moUes, surrounding the facial artery.
Branches of Distribution. These are five or six in number; they arise from the
lower part of the ganglion, and supply the mucous membrane of the mouth and
Wharton's duct, some being lost in the submaxillary gland. According to Meckel,
a branch from this ganglion occasionally descends in front of the Hyo-glossus
muscle, and, after joining with one from the hypo-glossal, passes to the Genio-
hyo-glossus muscle.
Eighth Pair.
The Eighth Pair consists of three nerves, the glosso-pharyngeal, pneumo-
gastric, and spinal accessory.
The Glosso-Phartngeal Nerve is dis-
tributed, as its name implies, to the tongue
and pharynx, being the nerve of sensation
to the mucous membrane of the fauces and
root of the tongue; and of motion, to the
Pharyngeal muscles. It arises by three or
four filaments, closely connected together, from
the upper part of the medulla oblongata, im-
mediately behind the olivary body.
Its deep origin may be traced through the
fasciculi of the lateral tract, to a nucleus of
grey matter at the lower part of the floor of
tlio fourth ventricle, external to the fasciculi
teretes. From its superficial origin, it passes outwjirds across the flocculus, and
260,— Origin of the Eighth Pair, their
Ganglia and Communications.
J'uuulnr Gan^i.
Tymjjnnic Itr
Trteumo-fjastr
EIGHTH PAIR.
495
leaves the skull at the central part of the jugular foramen, in a separate sheath
of the dura mater and arachnoid, in front of the pneumogastric and spinal acces-
sory nerves. In its passage through the jugular foramen, it grooves the lower
border of the petrous portion of the temporal bone, and, at its exit from the
skull, passes forwards between the jugular vein and internal carotid artei-y, and
descends in front of
the latter vessel and ^^i. — Course and Distribution of the Eighth Pair of Nerves.
beneath the styloid
process and the mus-
cles connected with
it, to the lower bor-
der of the Stylo-
pharyngeus. The
nerve now curves
inwards, forming an
arch on the side of
the neck, lying upon
the Stylo-pharyn-
geus, and the Mid-
dle constrictor of the
pharynx, above the
superior laryngeal
nerve. It then passes
beneath the Hyo-
glossus, and is finally
distributed to the
mucous membrane of
the fauces, and base
of the tongue, the
mucous glands of the
mouth and tonsil.
In passing through
the jugular foramen,
the nerve presents, in
succession, two gang-
liform enlargements.
The superior one,
the smaller, is called
the jugular gang-
lion, the inferior,
and larger one, the
petrous ganglion, or
the ganglion of An-
dersch.
The Superior, or
Jugular Ganglion,
is situated in the
upper part of the
groove in which the
nerve is lodged dur-
ing its passage
through the jugular
foramen. It is of very
small size, and in-
volves only the outer
side of the trunk of
the nerve, a small fasciculus passing beyond it, which is not connected directly
with it.
496 CRANIAL NERVES.
The Inferior, or Petrous Ganglion, is situated in a depression in the lower
border of tlie petrous portion of tlie temporal bone; it is larger than the foi'mer,
and involves the whole of the fibres of the nerve. From this ganglion arise those
filaments which connect the glosso-pharyngeal with other nerves at the base of
the skull.
Its Branches of Communication are with the pneumogastric, sympathetic, and
facial, and the tympanic branch.
The branches to the pneumogastric, are two filaments, one to its auricular
branch, and one to the upper ganglion of the pneumogastric.
The branch to the sympathetic is connected with the superior cervical
ganglion.
The branch of communication with the facial, perforates the posterior belly of
the digastric. It arises from the trunk of the nerve below the petrous ganglion,
and joins the facial just after its exit from the stylo-mastoid foramen.
The Tympanic Branch (Jacobson's nerve), arises from the petrous ganglion,
and enters a small bony canal on the base of the petrous portion of the temporal
bone. (This opening is placed on the bony ridge which separates the carotid
canal from the jugular fossa). It ascends to the tympanum, enters this cavity by
an aperture in its floor close to the inner wall, and divides into three branches,
which are contained in grooves upon the surface of the promontory.
Its branches of distribution are, one to the fenestra rotunda, one to the fenestra
ovalis, and one to the lining membrane of the Eustachian tube and tympanum.
Its branches of communication are three, and occupy separate grooves on the
surface of the promontory. One of these passes forwards and downwards to the
carotid canal to join the carotid plexus. A second runs vertically upwards to
join the greater superficial petrosal nerve, as it lies in the hiatus Fallopii. The
third branch runs upwards and forwards towards ihe anterior surface of the petrous
bone, and passes through a small aperture in the sphenoid and temporal bones, to
the exterior of the skull, where it joins the otic ganglion. This nerve, in its course
through the temporal bone, passes by the gangliform enlargement of the facial,
and has a connecting filament with it.
The branches of the glosso-pharyngeal nerve are the carotid, pharyngeal, mus-
cular, tonsillitic, and lingual.
The Carotid Branches descend along the trunk of the internal carotid artery
as far as its point of bifurcation, communicating with the pharyngeal branch of
the pneumogastric, and with branches of the sympathetic.
The Pharyngeal Branches are three or four filaments which unite opposite the
Middle constrictor of the pharynx with the pharyngeal branches of the pneumo-
gastric, superior laryngeal, and sympathetic nerves, to form the pharyngeal plexus,
branches from which perforate the muscular coat of the pharynx to supply the
mucous membrane.
The Muscular Branches are distributed to the Stylo-pharyngeus and Con-
strictors of the pharynx.
The Tonsillitic Branches supply the tonsil, forming a plexus (circulus tonsil-
laris) around this body, from which branches are distributed to the soft palate and
fauces, where they anastomose with the palatine nerves.
The Lingual Branches are two in number; one supplies the mucous membrane
covering the surface of the base of the tongue, the other perforates its substance,
and supplies the mucous membrane and papilla? of the side of the organ.
The Spinal Accessory Nerve consists of two parts; one, the accessory
part to the vagus, and the other the spinal portion.
The accessory part, the smaller of the two, arises by four or five delicate fila-
ments from the lateral tract of the cord below the roots of the vagus; these
filaments may be traced to a nucleus of grey matter at the back of the medulla,
below the origin of the vagus. It joins, in the jugular foramen, with the upper
ganglion of the vagus by one or two filaments, and is continued into the vagus
below the second ganglion. It gives branches to the pharyngeal and superior
laryngeal branches of the vagus.
EIGHTH PAIR.
497
The spinal portion, firm in texture, arises by several filaments from the lateral
tract of the cord, as low down as the sixth cervical nerve; the fibres pierce the
tract, and are connected with the anterior horn of the grey crescent of the cord.
This portion of the nerve ascends between the ligamentum denticulatum and the
posterior roots of the spinal nerves, enters the skull through the foramen mag-
num, and is then directed outwards to the jugular foramen, through which it
passes, lying in the same sheath as the pneumogastric, separated from it by a fold
of the arachnoid, and is here connected with the accessory portion. At its exit
from the jugular foramen, it passes backwards behind the internal jugular vein,
and descends obliquely behind the Digastric and Stylo-hyoid muscles to the upper
part of the Sterno-mastoid. It pierces this muscle, and passes obliquely across
the sub-occipital triangle, to terminate in the deep surface of the Trapezius.
This nerve gives several branches to the Sterno-mastoid during its passage
through it, and joins in its substance with branches from the third cervical.
In the sub-occipital triangle it joins with the second and third cervical nerves,
assists in the formation of the cervical plexus, and occasionally of the great
auricular nerve. On the front of the Trapezius, it is reinforced by branches
from the third, fourth, and fifth cervical nerves, joins with the posterior branches
of the spinal nerves, and is distributed to the Trapezius, some filaments ascending
and others descending in its substance as far as its inferior angle.
The Pneumogastric, or Vagus, one of the three divisions of the eighth pair,
has a more extensive distribution than any of the other cranial nerves, passing
through the neck and cavity of the chest to the upper part of the abdomen. It is
composed of both motor and sensitive filaments. It supplies the organs of voice and
respiration with motor and sensitive fibres; and the pharynx, oesophagus, stomach,
and heart with motor influence. Its superficial origin is by eight or ten filaments
from the lateral tract immediately behind the olivary body and below the glosso-
pharyngeal; its fibres may, however, be traced deeply through the fasciculi of the
medulla, to terminate in a grey nucleus near the lower part of the fioor of the
fourth ventricle. The filaments become united, and form a flat cord, which passes
outwards across the flocculus to the jugular foramen, through which it emerges
from the cranium. In passing through this opening, the pneumogastric accom-
panies the spinal accessory, being contained in the same sheath of dura mater
with it, a membranous septum separating it from the glosso-pharyngeal, which
lies in front. The nerve in this situation presents a well-marked ganglionic en-
largement, Avhich is called the ganglion jugulare, or the ganglion of the root of
the pneumogastric : to it the accessory part of the spinal accessory nerve is
connected. After the exit of the nerve from the jugular foramen, a second gangli-
form swelling is formed upon it, called the ganglion inferius, or the ganglion of,
the trunk of the nerve; below which it is again joined by filaments from the
accessory nerve. The nerve descends the neck in a straight direction within the
sheath of the carotid vessels, lying between the internal carotid artery and internal
jugular vein as far as the thyroid cartilage, and then between the same vein and
the common carotid to the root of the neck. Here the course of the nerve be-
comes different on the two sides of the body.
On the right side, the nerve passes across the subclavian artery between it and
the subclavian vein, and descends by the side of the trachea to the back part of the
root of the lung, where it spreads out in a plexiform network (posterior pulmonary),
from the lower part of which two cords descend upon the oesophagus, on which
they divide, forming, with branches from the opposite nerve, the oesophageal
plexus; below, these branches are collected into a single cord, which runs along
the back part of the oesophagus, enters the abdomen, and is distributed to the
posterior surface of the stomach, joining the left side of the caeliac plexus, and
the splenic plexus.
On the left side, the pneumogastric nerve enters the chest, between the left
carotid and subclavian arteries, behind the left innominate vein. It crosses the
K K
498 CRANIAL NERVES.
arch of the aorta, and descends behind the root of the left king and along the
anterior surface of the oesophagus to the stomach, distributing branches over its
anterior surface, some extending over the great cul-de-sac, and others along the
lesser curvature. Filaments from these latter branches enter the gastro-hepatic
omentum, and join the left hepatic plexus.
The Ganglion of the Root is of a greyish colour, circular in form, about
two lines in diameter, and resembles the ganglion on the large root of the fifth
nerve.
Connecting Branches. To this ganglion the accessory portion of the spinal
accessory nerve is connected by several delicate filaments; it also has an anasto-
motic twig with the petrous ganglion of the glosso-pharyngeal, with the facial
nerve by means of the auricular branch, and with the sympathetic by means of an
ascending filament from the superior cervical ganglion.
The Ganglion of the Trunk (inferior) is a ple:^iform cord, cylindrical in form,
of a reddish colour, and about an inch in length; it involves the whole of the
fibres of the nerve, except the portion of the accessory nerve derived from the
spinal accessory, which blends with the nerve beyond the gangl,ion.
Connecting Branches. This ganglion is connected with the hypo-glossal, the
superior cervical ganglion of the sympathetic, and with the loop between the first
and second cervical nerves.
The branches of the Pneumogastrie are
In the jugular fossa . . Auricular.
[ Pharyngeal
In the neck
J Superior laryngeal.
I Recurrent laryngeal.
\ Cervical Cardiac.
( Thoracic Cardiac.
T ,1 ,1 j Anterior pulmonary.
in the thorax . . .\-r^ . ■ ^
I Posterior pulmonary.
[. Oesophageal.
In the abdomen . . Gastric.
The Auricular Branch arises from the ganglion of the root, and is joined soon
after its origin by a filament from the glosso-pharyngeal; it crosses the jugular
fossa to an opening near the root of the styloid process. Traversing the substance
of the temporal bone, it crosses the aqueductus Fallopii about two lines above its
termination at the stylo-mastoid foramen; it here gives ofi" an ascending branch,
which joins the facial, and a descending branch, which anastomoses with the pos-
terior auricular branch of the same nerve: the continuation of the nerve reaches
the surface between the mastoid jarocess and the external auditory meatus, and
supplies the integument at the back part of the pinna.
The Pharyngeal Branch arises from the upper part of the inferior ganglion of
the pneumogastrie, receiving a filament from the accessory portion of the spinal
accessory; it passes across the internal carotid artery (in front or behind), to the
upper border of the Middle constrictor, where it divides into numerous filaments,
which anastomose with those from the glosso-pharyngeal, superior laryngeal, and
sympathetic, to form the pharyngeal plexus,- from which branches are distributed
to the muscles and mucous membrane of the pharynx. As this nerve crosses the
internal carotid, some filaments are distributed, together with those from the
glosso-pharyngeal, upon the wall of this vessel.
The Superior Laryngeal Nerve, larger than the preceding, arises from the
middle of the inferior ganglion of the pneumogastrie. It descends, by the side
of the pharynx, behind the internal carotid, where it divides into two branches,
the external and internal laryngeal
The external larnygeal branch, the smaller, descends by the side of the
larynx, beneath the Sterno-thyroid, to supply the crico-thyroid and the thyroid
BRANCHES OF PNEUMOGASTRIC.
499
gland. It gives branches to the pharyngeal plexus, and the Inferior constrictor,
and communicates with the superior cardiac nerve, behind the common carotid.
The Internal Laryngeal Branch descends to the opening in the thyro-hyoid
membrane, through which it passes with the superior laryngeal artery, and is
distributed to the mucous membrane of the larynx, and the Ai-ytenoid muscle,
anastomosing with the recurrent laryngeal.
The branches to the mucous membrane are distributed, some in front, to the
epiglottis, the base of the tongue, and epiglottidean gland; and others pass back-
wards, in the aryteno-epiglottidean fold, to supply the mucous membrane sur-
rounding the superior orifice of the larynx, as well as the membrane which lines
the cavity of the larynx as low down as the vocal chord.
The filament to the Arytenoid muscle is distributed partly to it, and part to
the mucous lining of the larynx.
'YhQ filament which joins with the recurrent laryngeal, descends beneath the
mucous membrane on the posterior surface of the larynx, behind the lateral part
of the thyroid cartilage, where the two nerves become united.
The Inferior, or Recurrent Laryngeal, so called from its reflected course,
arises, on the right side, in front of the subclavian artery: it winds round this
vessel, and ascends obliquely to the side of the trachea, behind the common
carotid and inferior thyroid arteries. On the left side, it arises in front of the
arch of the aorta, and winds round it at the point where the obliterated remains
of the ductus arteriosus are connected with this vessel, and then ascends to the
side of the trachea. The nerves on both sides ascend in the groove between the
trachea and oesophagus, and, piercing the lower fibres of the Inferior constrictor
muscle, enter the larynx behind the articulation of the inferior cornu of the
thyroid cartilage with the cricoid, being distributed to all the muscles of the
larynx, excepting the Crico-thyroid, and joining with the superior laryngeal.
The recurrent laryngeal, as it winds round the subclavian artery and aorta,
gives ofi" several cardiac filaments, which unite with the cardiac branch from the
pneumogastric and sympathetic. As it ascends the neck, it gives off oesophageal
branches, more numerous on the left than on the right side; tracheal branches to
the posterior membranous portion of the trachea; and some pharyngeal filaments
to the Inferior constrictor of the pharynx.
The Cervical Cardiac Branches, two or three in number, arise from the
pneumogastric, at the upper and lower part of the neck.
The superior branches are small, and communicate with the cardiac branches
of the sympathetic, and with the great cardiac plexus.
The inferior cardiac branches, one on each side, arise at the lower part
of the neck, just above the first rib. On the right side, this branch passes in
front of the arteria innominata, and anastomoses with the superior cardiac nerve.
On the left side, it passes in front of the arch of the aorta, and anastomoses
either with the superior cardiac nerve, or with the cardiac plexus.
The Thoracic Cardiac Branches, on the right side, arise from the trunk of
the pneumogastric, as it lies by the side of the trachea: passing inwards, they
terminate in the deep cardiac plexus. On the left side, they arise from the left
recurrent laryngeal nerve.
The Anterior Pulmonary Branches, two or three in number, and of small size,
are distributed on the anterior aspect of the root of the lungs. They join with
filaments from the sympathetic, and form the anterior pulmonary plexus.
The Posterior Pulmonary Branches, more numerous and larger than the ante-
rior, are distributed on the posterior aspect of the root of the lung: they are joined
by filaments from the third and fourth thoracic ganglia of the sympathetic, and
form the posterior pulmonary plexus. Branches from both plexuses accompany
the ramifications of the air tubes through the substance of the lungs.
The (Esophageal Branches are given off from the pneumo-gastric, both above
and below the pulmonary branches. The latter are the most numerous and
K K 2
500 CRANIAL NERVES.
largest. They form, together with branches from the opposite nerve, the oeso-
phageal plexus.
The Gastric Branches are the terminal filaments of the pneumo-gastric nerve.
The nerve on the right side is distributed to the posterior surface of the stomach,
and joins the left side of the coeliac plexus, and the splenic plexus. The nerve
on the left side is distributed over the anterior surface of the stomach, some
filaments passing across the great cul-de-sac, and others along the lesser curvature.
They unite with branches of the right nerve and sympathetic, some filaments
passing through the lesser omentum to the left hepatic plexus.
The Spinal Nerves.
THE Spinal Nerves are so called, from taking their origin from the spinal cord,
and from being transmitted through the intervertebral foramina on either side
of the spinal column. There are thirty-one pairs of spinal nerves, which are
arranged into the following groups, corresponding to the region of the spine
through which they pass:
Cervical ... 8 pairs.
Dorsal . . . I2 „
Lumbar . . . 5 35
Sacral . . . 5 „
Coccygeal . . . i ,?
It will be observed, that each group of nerves corresponds in number with the
vertebrae in each region, excepting in the cervical and coccygeal.
Each spinal nerve arises by two roots, an anterior, or motor root, and a
posterior, or sensitive root.
Roots of the Spinal Nerves.
The anterior roots arise somewhat irregularly from a linear series of foramina,
on the antero-lateral column of the spinal cord, gradually approaching towards
the anterior median fissure as they descend.
The fibres of the anterior roots pass between the anterior and lateral columns,
and enter the grey matter of ihe anterior horn, where they divide into two
bundles, the larger of which is connected with the lateral column of the same
side, while the smaller bundle passes to the anterior column of the opposite side.
The component fibres of the latter bundle form part of the anterior white com-
missure, and decussate with the roots of the nerve of the opposite side of the
cord.
The posterior roots arise, in a perfectly straight line, from the posterior lateral
fissure, opposite the corresponding horn of grey matter.
The fibres of the posterior roots pass directly into the grey matter of the
posterior horn, at the bottom of the posterior lateral fissure, where they sub-
divide, some passing into the lateral and posterior columns of the same side;
while others enter the grey commissure, and form the transverse commissural
fibres connecting these roots with the opposite side of the cord.
The posterior roots of the nerves are larger, and the individual filaments more
numerous, and thicker, than those of the anterior. As their component fibrils
pass outwards, towards the aperture in the dura mater, they coalesce into two
bundles, receive a tubular sheath from this membrane, and enter the intervertebral
ganglion which is developed upon each root.
The posterior root of the first cervical nerve forms an exception to these
characters. It is smaller than the anterior, has frequently no ganglion developed
upon it, and, when the ganglion exists, it is often situated within the dura mater.
The anterior roots are the smaller of the two, devoid of any ganglionic
enlargement, and their component fibrils are collected into two bundles, near the
intervertebral foramina.
Ganglia of the Spinal Nerves.
A ganglion is developed upon each posterior root of the spinal nerves.
These ganglia are of an oval form, of a reddish colour, bear a proportion in
502 SPINAL NERVES.
size to the nerves upon which they are formed, and are placed in the interver-
tebral foramina, external to the point where the nerves perforate the dura mater.
Each ganglion is bifid internally, where it is joined by the two bundles of the poste-
rior root, the two portions being united into a single mass externally. The ganglia
upon the first and second cervical nerves form an exception to these characters,
being placed on the arches of the vertebras over which they pass. The ganglia,
also, of the sacral nerves are placed within the spinal canal; and that on the
coccygeal nerve, also in the canal about the middle of its posterior root. Imme-
diately beyond the ganglion, the two roots unite, and the trunk thus formed
passes out of the intervertebral foramen, and divides into an anterior branch, for
the supply of the anterior part of the body; and a posterior branch, for the
posterior part.
Anterior Branches op the Spinal Nerves.
The anterior branches of the Spinal Nerves supply the parts of the body
in front of the spine, including the limbs. They are for the most part larger
than the posterior branches; this increase of size being proportioned to the larger
extent of structures they are required to supply. Each branch is connected by
slender filaments with the sympathetic. In the dorsal region, the anterior branches
of the spinal nerves are completely separate from each other, and are uniform in
their distribution; but in the cervical, lumbar, and sacral regions, they form
intricate plexuses previous to their distribution.
Posterior Branches of the Spinal Nerves.
The posterior branches of the Spinal Nerves are generally smaller than the
anterior: they arise from the trunk, resulting from the union of the nerves in the
intervertebral foramina, and, passing backwards, divide into external and internal
branches, which are distributed to the muscles and integument behind the spine.
The first cervical and lower sacral nerves are exceptions to these characters.
Cervical Nerves.
The roots of the Cervical Nerves increase in size from the first to the fifth,
and then maintain the same size to the eighth. The posterior roots bear a pro-
portion to the anterior as 3 to I, which is much greater than in any other region;
the individual filaments being also much larger than those of the anterior roots.
In direction, they are less oblique than those of the other spinal nerves. The
first is directed a little upwards and outwards; the second is horizontal; the
others are directed obliquely downwards and outwards, the lowest being the
most oblique, and consequently longer than the upper, the distance between their
place of origin and their point of exit from the spinal canal, never exceeding the
depth of one vertebra.
The trunk of the first Cervical Nerve {Sub-occipital), leaves the spinal canal,
between the occipital bone and the posterior arch of the atlas; the second between
the posterior arch of the atlas and the lamina of the axis; and the eighth (the
last), between the last cervical and first dorsal vertebrae.
Each nerve, at its exit from the intervertebral foramen, divides into an anterior
and a posterior branch. The anterior branches of the four upper cervical nerves,
form the cervical plexus. The anterior branches of the four lower cervical nerves,
together with the first dorsal, form the brachial plexus.
Anterior Branches of the Cervical Nerves.
The anterior branch of the first, or Sub -occipital Nerve, is of small size. It
escapes from the vertebral canal, through a groove upon the posterior arch of the
atlas. In this groove it lies beneath the vertebral artery, to the inner side of the
Rectus lateralis. As it crosses the foramen in the transverse process of the
CERVICAL PLEXUS.
503
atlas, it receives a filament from the sympathetic. It then descends, in front of
this process, to communicate with an ascending branch from the second cervical
nerve.
Communicating filaments from this nerve join the pneumogastric, the hypo-
glossal and sympathetic, and some branches are distributed to the Rectus lateralis,
and the two Anterior recti. According to Valentin, it also distributes filaments
to the occipito-atloid articulation, and mastoid process of the temporal bone.
The anterior branch of the second Cervical Nerve escapes from the spinal
canal, between the posterior arch of the atlas and the lamina of the axis, and,
passing forwards on the outer side of the vertebral artery, divides in front of the
Intertransverse muscle, into an ascending branch, which joins the first cervical;
and two descending branches which join the third.
The anterior branch of the third Cervical Nerve is double the size of the
preceding. At its exit from the intervertebral foramen, it passes downwards and
outwards beneath the Sterno-mastoid, and divides into two branches. The
ascending branch joins the anterior division of the second cervical, communicates
with the sympathetic and spinal accessory nerves, and subdivides into the super-
ficial cervical, and great auricular nerves. The descending branch passes down
in front of the Scalenus anticus, anastomoses with the fourth cervical nerve, and
becomes continuous with the clavicular nerves.
The anterior branch of the fourth Cervical is of the same size as the pre-
ceding. It receives a branch from the third, sends a communicating branch
to the fifth cervical, and, passing downwards and outwards, divides into numerous
filaments, which cross the posterior triangle of the neck, towards the clavicle and
acromion. It usually gives a branch to the phrenic nerve whilst it is contained
in the intertransverse space.
The anterior branches of the fifth, sixth, seventh, and eighth Cervical-
Nerves, are remarkable for their large size. They are much larger than the
preceding nerves, and are all of equal size. They assist in the formation of
the brachial plexus.
Cervical Plexus.
The cervical plexus (fig. 256) is formed by the anterior branches of the four
upper cervical nerves. It is situated in front of the four upper vertebrae, resting
upon the Levator anguli scapula, and Scalenus medius muscles, and covered in by
the Sterno-mastoid.
Its branches may be divided into two groups, superficial and deep, which may
be thus arranged:
iSuperficialis colli.
Auricularis magnus.
Occipitalis minor
ouperjiciai ^ ^
I
! Sternal.
Clavicular.
Acromial.
( Communicating.
J Muscular.
\ Communicans noni.
Internal
Deep -^ ( Phrenic.
T-, , , ( Communicating.
External < ht i
( Muscular.
Superficial Branches of the Cervical Plexus.
The Superficialis Colli arises from the second and third cervical nerves, turns
round the posterior border of the Sterno-mastoid about its middle, and passing
obliquely forwards behind the external jugular vein to the anterior border of that
muscle, perforates the deep cervical fascia, and diVideSu beneath the Platysma into
two branches, which are distributed to the anterior and lateral parts of the neck.
504 SPINAL NERVES.
The ascending branch gives a filament, which accompanies the external
juguhxr vein; it then passes upwards to the sub-maxillary region, and divides into
branches, some of which form a plexus with the cervical branches of the facial
nerve beneath the Platysma; others pierce this muscle, supply it, and are distri-
buted to the integument of the upper half of the neck, at its fore part, as high up
as the chin.
The descending branch pierces the Platysma, and is distributed to the integu-
ment of the side and front of the neck, as low as the sternum.
This nerve is occasionally represented by two or more filaments.
The Auricularis Magnus is the largest of the ascending branches. It arises
from the second and third Cervical nerves, winds round the posterior border of
the Sterno-mastoid, and, after perforating the deep fascia, ascends upon that
muscle beneath the Platysma to the parotid gland, where it divides into numerous
bi'anches.
The facial branches pass across the parotid, and are distributed to the inte-
gument of the face; others penetrate the substance of the gland, and communi-
cate with the facial nerve.
. The posterior or auricular branches ascend vertically to supply the integu-
ment of the posterior part of the pinna, communicating with the auricular branches
of the facial and pneumogastric nerves.
The mastoid branch joins the posterior auricular branch of the facial, and
crossing the mastoid process, is distributed to the integument behind the ear.
The Occipitalis Minor arises from the second cervical nerve; it curves round
the posterior border of the Sterno-mastoid above the preceding, and ascends ver-
tically along the posterior border of this muscle to the back part of the side of the
head. Near the cranium it perforates the deep _.fascia, and is continued upwards
along the side of the head behind the ear, supplying the integument and Occipito-
frontalis muscle, and communicating with the occipitalis major, auricularis
magnus, and posterior auricular branch of the facial.
This nerve gives off an auricular branch, which supplies the Attollens aurem
and the integument of the upper and back part of the auricle. This branch is
occasionally derived from the great occij)ital nerve. The occipitalis minor varies
in size; it is occasionally double.
The Descending or Supra-clavicular Branches arise from the third and fourth
cervical nerves; emerging beneath the posterior border of the Sterno-mastoid,
they descend in the interval between this muscle and the Trapezius, and divide
into branches, which are arranged, according to their position, into three groups.
The inner or sternal branch crosses obliquely over the clavicular and sternal
attachments of the Sterno-mastoid, and supplies the integument as far as the
median line.
The middle or clavicular branch crosses the clavicle, and supplies the integu-
ment over the Pectoral and Deltoid muscles, communicating with the cutaneous
branches of the upper intercostal nerves. Not unfrequently, the supra-clavicular
nerve passes through a foramen in the clavicle, at the junction of the outer with
the inner two-thirds of the bone.
The external or acromial branch passes obliquely across the outer surface of
the Trapezius and the acromion, and supplies the integument of the upper and
back part of the shoulder.
Deep Branches of the Cervical Plexus. Internal Series.
The Cotnmunicating Branches consist of several filaments, which pass from the
loop between the first and second cervical nerves in front of the atlas to the pneu-
mogastric, hypo-glossal, and sympathetic.
Muscular Branches supply the Anterior recti and Rectus lateralis muscles;
they proceed from the first cervical nerve, and from the loop formed between
it and the second.
COMMUNICANS NONI; PHRENIC. 505
The Communicans Noni (fig. 256) consists usually of two filaments, one being
derived from the second, and the other from the third cervical. These filaments
descend vertically downwards on the outer side of the internal jugular vein, cross
in front of the vein a little below the middle of the neck, and form a loop with
the descendens noni in front of the sheath of the carotid vessels. Occasionally,
the junction of these nerves takes place within the sheath.
The Phrenic Nerve {Internal Respiratory of Bell) arises from the third and
fourth cervical nerves, and receives a communicating branch from the fifth. It
descends to the root of the neck, lying obliquely across the front of the Scalenus
anticus, passes over the first part of the subclavian arteiy, between it and the
subclavian vein, and, as it enters the chest, crosses the internal mammary artery
near its root. Within the chest, it descends nearly vertically in front of the root
of the lung, and by the side of the pericardium, between it and the mediastinal
portion of the pleura, to the Diaphragm, where it divides into branches, which
separately pierce that muscle, and are distributed to its under surface.
The two phrenic nerves differ in their length, and also in their relations at the
upper part of the thorax.
The right nerve is situated more deeply, and is shorter and more vertical
in direction than the left; it lies on the outer side of the right vena innominata
and superior vena cava.
The left nerve is rather larger than the right, from the inclination of the
heart to the left side, and from the Diaphragm being lower in this than on the
opposite side. At the upper part of the thorax, it crosses in front of the arch of
the aorta to the root of the lung.
Each nerve supplies filaments to the pericardium and pleura, and near the
chest is joined by a filament from the sympathetic; by another derived from the
fifth and sixth cervical nerves; and occasionally by one from the union of the
descendens noni with the spinal nerves, which. Swan states, occurs only on the
left side.
From the right nerve, one or two filaments pass to join in a small ganglion
with phrenic branches of the solar plexus; and branches from this ganglion are
distributed to the hepatic plexus, the supra-renal capsule, and inferior vena cava.
From the left nerve filaments pass to join the phrenic plexus, but without any
ganglionic enlargement.
Deep Bkajstches of the Cervical Plexus. External Series.
Communicating Branches. The cervical plexus communicates with the spinal
accessory nerve, in the substance of the Sterno-mastoid muscle, in the sub-occi-
pital triangle, and beneath the Trapezius.
Muscular Branches are distributed to the Sterno-mastoid, Levator anguli
scapulae. Scalenus medius, and Trapezius.
The branch for the Sterno-mastoid is derived from the second cervical; the
Levator anguli scapulse receiving branches from the third; and the Trapezius
branches from the third and fourth.
Posterior Branches of the Cervical Nerves.
The Posterior Branches of the cervical nerves, with the exception of the first
two, pass backwards, and divide, behind the posterior Intertransverse muscles, into
external and internal branches.
The external branches supply the muscles at the side of the neck, viz., the
Cervicalis ascendens, Transversalis colli, and Trachelo-mastoid.
The external branch of the second cervical nerve is the largest; it is often
joined with the third, and supplies the Complexus, Splenius, and Trachelo-
mastoid muscles.
The internal branches, the larger, are distributed differently in the upper and
lower part of the neck. Those derived from the third, fourth, and fifth nerves
pass between the Semi-spinalis and Complexus muscles, and having reached the
5o6 SPINAL NERVES.
spinous processes, perforate the aponeurosis of tlie Splenius and Trapezius, and
are continued outwards to the integument over the Trapezius; whilst tliose derived
from the three lowest cervical nerves are the smallest, and are placed beneath the
Semi-spinalis, which they supply, and do not furnish any cutaneous filaments.
These internal branches supply the Complexus, Semi-spinalis colli, Inter-spinales,
and Multifidus spinse.
The posterior branches of the three first cervical nerves require a separate
description.
The posterior branch of the First Cervical Nerve {Sub-occipital) is larger
than the anterior, and escapes from the vertebral canal between the occipital bone
and the posterior arch of the atlas, lying behind the vertebral artery, and enters
the triangular space formed by the Rectus posticus major, the Obliquus superior,
and Obliquus inferior. It supplies the Recti and Obliqui muscles, and the com-
plexus. From the branch which supplies the Inferior oblique a filament is given
off, which joins the second cervical nerve. It also occasionally gives oiF a cuta-
neous filament, which accompanies the occipital artery, and communicates with
the occipitalis major and minor nerves.
The posterior division of the first cervical has no branch analogous to the
external branch of the other cervical nerves.
The posterior branch of the Second Cervical Nerve is three or four times
greater than the anterior branch, and the largest of all the other posterior cervical
nerves. It emerges from the spinal canal between the posterior arch of the atlas
and lamina of the axis, below the Inferior oblique. " It supplies this muscle, and
receives a communicating filament from the first cervical. It then divides into
external and internal branches.
The internal branch, called, from its size and distribution, the occipitalis major,
ascends obliquely inwards between the Obliquus inferior and Complexus, and
pierces the latter muscle and the Trapezius near their attachments to the cranium.
It is now joined by a filament from the third cervical nerve, and ascending on the
back part of the head with the occipital artery, divides into two branches, which
supply the integument of the scalp as far forwards as the vertex, communicating
with the occipitalis minor. It gives ofi" an auricular branch to the back part of
the ear, and muscular branches to the Complexus.
The posterior branch of the Third Cervical is smaller than the preceding, but
larger than the fourth; it differs from the posterior branches of the other cervical
nerves in its supplying an additional filariaent to the integument of the occiput.
This occipital branch arises from the internal or cutaneous branch beneath the
Trapezius; it pierces that muscle, and supplies the skin on the lower and back part
of the head. It lies to the inner side of the occipitalis major, with which it is con-
nected.
The internal branches of the posterior divisions of the three first cervical
nerves are occasionally joined beneath the Complexus by communicating branches.
This communication has been described by Cruvelhier as the posterior cervical
plexus.
The Brachial Plexus (fig. 262).
The brachial plexus is formed by the union of the anterior branches of the four
lower cervical and first dorsal nerves. It extends from the lower part of the side
of the neck to the axilla, being very broad, and presenting but little of a plexi-
form arrangement at its commencement, narrow opposite the clavicle, broad and
presenting a more dense interlacement in the axilla, and dividing opposite the
coracoid process into numerous branches for the supply of the upper limb. These
nerves are all similar in size, and their mode of union in the formation of the
plexus is the following. The fifth and sixth nerves unite near their exit from
the spine into a common trunk; the seventh nerve joins this trunk near the outer
border of the Middle scalenus; and the three nerves thus form one large single
cord. The eighth cervical and first dorsal nerves unite beneath the Anterior
BRACHIAL PLEXUS.
507
of Clavic
scalenus into a common trunk. Thus two large trunks are formed, the upper one
by the union of the fifth, sixth, and seventh cervical; and the lower one by the
eighth cervical and first dorsal. These two trunks accompany the subclavian
artery to the axilla, lying upon its outer side, that formed by the union of the last
cervical and first dorsal
being nearest to the vessel. 262. — Plan of the Brachial Plexus.
Opposite the clavicle, and
sometimes in the axilla,
each of these cords gives
oiF a fasciculus, which
uniting, a third trunk is
formedj so that in the
centre of the axilla three
cords are found, one lying
on the outer side of the
axillary artery, one on its
inner side, and one behind.
The brachial plexus com-
municates with the cer-
vical plexus by a branch
from the fourth to the
fifth nerve, and with the
phrenic by a branch from
the 'fifth cervical, which
joins that nerve on the
Anterior scalenus muscle:
the cervical and first dor-
sal nerves are also joined
by filaments from the mid-
dle and inferior cervical
ganglia of the sympathetic,
close to their exit from the
intervertebral foramina.
Relations. In the neck, the brachial plexus lies at first between the Anterior
and Middle scaleni muscles, and then above and to the outer side of the subcla-
vian artery; it then passes beneath the clavicle and Subclavius muscle, lying
upon the first serration of the Serratus magnus and Subscapularis muscles. In
the axilla, it is placed on the outer side of the first portion of the axillary artery:
it surrounds the artery in the second part of its course, one cord lying upon the
outer side of that vessel, one on the inner side, and one behind it; and at the
lower part of the axillary space gives off its terminal branches to the upper
extremity.
Branches. The branches of the brachial plexus may be arranged into two
groups, viz., those given off above the clavicle, and those below that bone.
Branches above the Clavicle.
Communicating. Posterior thoracic.
Muscular. Supra-scapular.
The communicating branch with the phrenic is derived from the fifth cervical
nerve; it joins the phrenic on the Anterior scalenus muscle.
The muscular branches supply the Longus colli, Scaleni, Rhomboidei, and
Subclavius muscles. Those for the Scaleni and Longus colli arise from the lower
cervical nerves at their exit from the intervertebral foramina. The rhomboid
branch arises from the fifth cervical, pierces the Scalenus medius, and passes
beneath the Levator anguli scapulre, which it occasionally supplies, to the Rhom-
boid muscles. The subclavian branch is a small filament, which arises from the
5o8 SPINAL NER\^S.
trunk formed by the junction of the fifth and sixth cervical nerves; it descends
in front of the subclavian artery to the Subclavius muscle, and is usually connected
by a filament with the phrenic nerve.
The Posterior Thoracic Nerve (long thoracic, external respiratory of Bell),
supplies the Serratus magnus, and is remarkable for the length of its course. It
arises by two roots, from the fifth and sixth cervical nerves, immediately after
their exit from the intervertebral foramina. These unite in the substance of the
Middle scalenus muscle, and, after emerging from it, the nerve passes down behind
the brachial plexus and the axillary vessels, resting on the outer surface of the
Serratus magnus. It extends along the side of the chest to the lower border of
this muscle, and supplies it with numerous filaments.
The Supra- Scapular Nerve arises from the cord formed by the fifth, sixth,
and seventh cervical nerves: passing obliquely outwards beneath the Trapezius,
it enters the supra-spinous fossa, through the notch in the upper border of the
scapula; and, passing beneath the Supra-spinatus muscle, curves in front of the
spine of the scapula to the infra-spinous fossa. In the supra-spinous fossa, it
gives ofi" two branches to the Supra-spinatus muscle, and an articular filament to
the shoulder-joint ; and in the infra-spinous fossa, it gives ofi" two branches
to the Infra-spinatus muscle, besides some filaments to the shoulder -joint and
scapula.
Branches Below the Clavicle.
To chest . Anterior thoracic.
rr, 1 11 ( Subscapular.
io shoulder s „. \
( Lircumtiex.
SMusculo-cutaneous,
Internal cutaneous.
Lesser internal cutaneous.
Median.
Ulnar.
Musculo-spiral.
The branches given ofi" below the clavicle, are derived from the three cords of
the brachial plexus, in the following manner:
From the outer cord, arises the external of the two anterior thoracic nerves,
the musculo-cutaneous nerve, and the outer head of the median.
From the inner cord, arises the internal of the two anterior thoracic nerves,
the internal cutaneous, the lesser internal cutaneous (nerve of Wrisberg), the
ulnar, and inner head of the median.
From the posterior cord, arises the subscapular; and it then subdivides into the
musculo-spiral and circumflex nerves.
The Anterior Thoracic Nerves, two in number, supply the Pectoral muscles.
The external, or superficial branch, the larger of the two, arises from the outer
cord of the brachial plexus, passes inwards, across the axillary artery and vein,
and is distributed to the under surface of the Pectoralis major. It sends down a
communicating filament to join the internal branch.
The internal, or deep branch, arises from the inner cord, and passes upwards
between the axillary artery and vein (sometimes perforates the vein), and joins with
the filament from the superficial branch. From the loop thus formed, branches
are distributed to the under surface of the Pectoralis minor and major muscles.
The Subscapular Nerves are three in number, and supply the Subscapularis,
Teres major, and Latissimus dorsi muscles.
The upper subscapular nerve, the smallest, enters the upper part of the
Subscapularis muscle.
The lower subscapular nerve enters the axillary border of the Subscapularis,
and terminates in the Teres major. The latter muscle is sometimes supplied by
a separate branch.
CUTANEOUS NERVES OF THE FORE-ARM.
509
263. — Cutaneous Nerves of Right Upper
Extremity. Anterior View.
The long subscapular, the largest of the three, descends along the lower
border of the Subscapularis to the Latissimus dorsi, through which it may be
traced as far as its lower border.
The Circumjiex Nerve supplies some of the muscles, and the integument of the
shoulder, and the shoulder -joint. It
arises from the posterior cord of the
brachial plexus, in common with the
musculo-spiral nerve. It passes down
behind the axillary artery, and in front
of the Subscapularis; and, at the lower
border of this muscle, passes backwards,
and divides into two branches.
The superior branch winds round the
neck of the humerus, beneath the Del-
toid, with the posterior circumflex vessels,
as far as the anterior border of this muscle,
supplying it and giving off cutaneous
branches, which pierce it to ramify in the
integument covering its lower part.
The inferior branch, at its origin, dis-
tributes filaments to the Teres minor and
back part of the Deltoid muscles; upon
the filament to the former muscle a gan-
gliform enlargement usually exists. The
nerve then pierces the deep fascia, and
supplies the integument over the lower
two-thirds of the posterior surface of the
Deltoid, as well as that covering the long
head of the Triceps.
The circumflex nerve, before its divi-
sion, gives off an articular filament, which
enters the shoulder-joint below the Sub-
scapularis.
The Musculo- Cutaneous Nerve (ex-
ternal cutaneous, J9er/b^■a?^5 Gasserii), sup-
plies some of the muscles of the arm, and
the integument of the fore-arm. It arises
from the outer cord of the brachial plexus,
opposite the lower border of the Pecto-
ralis minor. It then perforates the Coraco-
brachialis muscle, and passes obliquely
between the Biceps and Brachialis anti-
cus, to the outer side of the arm, a little
above the elbow, where it perforates the
deep fascia and becomes cutaneous. This
nerve, in its course through the arm, sup-
plies the Coraco-brachialis, Biceps, and
Brachialis anticus muscles, besides some
filaments to the elbow-joint and humerus.
The cutaneous portion of the nerve
passes behind the median cephalic vein,
and divides, opposite the elbow-joint, into an anterior and a posterior branch.
The anterior branch descends along the radial border of the fore-arm to the
wrist. It is here placed in front of the radial artery, and, piercing the deep
fascia, accompanies that vessel to the back of the wrist. It communicates with
a branch from the radial nerve, and distributes filaments to the integument of the
ball of the thumb, and to the wrist-joint.
510
SPINAL NEEVES.
264. — Cutaneous Nerves of Eight Upper
Extremity. Posterior View.
The posterior branch is given off about the middle of the fore-arm, and passes
downwards, along the back part of its radial side, to the wrist. It supplies the
integument of the lower third of the fore-arm, communicating with the radial
nerve, and the external cutaneous branch of the musculo-spiral.
The Internal Cutaneous Nerve is one
of the smallest branches of the brachial
plexus. It arises from the inner cord,
in common with the ulnar and internal
head of the median, and, at its commence-
ment, is placed on the inner side of the
brachial artery. It passes down the inner
side of the arm, pierces the deep fascia
with the basilic vein, about the middle of
the limb, and,, becoming cutaneous, di-
vides into two branches.
This nerve gives off, near the axilla, a
cutaneous filament, which pierces the
fascia, and supplies the integument cover-
ing the Biceps muscles, nearly as far as
the elbow. This filament lies a little ex-
ternal to the common trunk from which
it arises.
The anterior branch, the larger of the
two, passes in front of, occasionally be-
hind, the median basilic vein. It then
descends on the anterior surface of the
ulnar side of the fore-arm, distributing
filaments to the integument as far as the
wrist, and communicating with a cuta-
neous branch of the ulnar nerve.
The posterior branch, passes obliquely
downwards on the inner side of the basilic
vein, winds over the internal condyle of
the humerus to the back of the fore -arm,
and descends, on the posterior surface of
its ulnar side, to a little below the middle,
distributing filaments to the integument.
It anastomoses above the elbow, with
the lesser internal cutaneous, and above
the wrist, with the dorsal branch of the
ulnar nerve (Swan).
The Lesser Internal Cutaneous Nerve
(nerve of Wrisberg), is distributed to
the integument on the inner side of the
arm. It is the smallest of the branches
of the brachial plexus, and usually arises
from the inner cord, with the internal
cutaneous and ulnar nerves. It passes
through the axillary space, at first lying
beneath, and then on the inner side, of
the axillary vein, and communicates with
the intercosto-humeral nerve. It then
descends along the inner side of the bra-
chial artery, to the middle of the arm,
where it pierces the deep fascia, and is
distributed to the integument of the back part of the lower third of the arm,
extending as far as the elbow, where some filaments are lost in the integument in
MEDIAN.
511
front of the inner condyle, and others over the olecranon. It communicates with
the inner branch of the internal cutaneous nerve.
In some cases, the nerve of Wrisberg and intercosto-humeral, are connected by-
two or three filaments, which form a kind of plexus at the back part of the axilla.
In other cases, the intercosto-humeral is of large size, and takes the place of the
nerve of Wrisberg, receiving merely a filament of communication from the
brachial plexus, which represents this nerve. In other cases, this filament is
wanting, the place of the nerve of Wrisberg being supplied entirely from the
intercosto-humeral.
The Median Nerve (fig. 265) has received its name from the course it takes
along the middle line of the arm and fore-arm to the hand, lying between the
ulnar and musculo-spiral and radial nerves. It arises by two roots, one from the
outer, and one from the inner cord of the brachial plexus; these embrace the lower
part of the axillary artery, uniting either in front or on the outer side of that
vessel. As it descends through the arm, it lies at first on the outer side of the
brachial artery, crosses that vessel in the middle of its course, usually in front,
but occasionally behind it, and lies on its_^ inner side to the bend of the elbow,
where it is placed beneath the bicipital fascia, and is separated from the elbow-
joint by the Brachialis anticus. In the fore-arm, it passes between the two heads
of the Pronator radii teres, and descends beneath the Flexor sublimis, to within
two inches above the annular ligament, where it becomes more superficial, lying
between the Flexor sublimis and Flexor carpi radialis, covered by the integument
and fascia. It then passes beneath the annular ligament into the hand.
Branches. No branches are given off from the median nerve in the arm.
In the fore-arm, its branches are, muscular, anterior interosseous, and palmar
cutaneous.
The muscular branches supply all the superficial layer of muscles on the ante-
rior surface of the fore-arm, except the Flexor carpi ulnaris. These branches
are derived from the nerve near the elbow. The branch furnished to the Pronator
radii teres often arises above the joint.
The anterior interosseous supplies the deep muscles on the anterior surface of
the fore-arm. It accompanies the anterior interosseous artery along the inter-
osseous membrane, in the interval between the Flexor longus pollicis and Flexor
profundus digitorum muscles, both of which it supplies, and terminates below in
the Pronator quadratus.
The palmar cutaneous branch arises from the median nerve at the lower
part of the fore-arm. It pierces the fascia above the annular ligament, and di-
vides into two branches; the outer one supplies the skin over the ball of the
thumb, and communicates with the external cutaneous nerve; the inner one sup-
plies the integument of the palm of the hand, anastomosing with the cutaneous
branch of the ulnar. Both nerves cross the annvilar ligament previous to their
distribution.
In the palm of the hand, the median nerve is covered by the integument and
palmar fascia, and rests upon the tendons of the Flexor muscles. In this situation
it becomes enlarged, somewhat flattened, of a reddish colour, and divides into two
branches. Of these, the external one supplies a muscular branch to some of the
muscles of the thumb, and digital branches to the thumb and index finger; the
internal branch supplying digital branches to the middle finger and part of the
index and ring fingers.
The branch to the muscles of the thumb is a short nerve, which subdivides to
supply the Abductor, Opponens, and outer head of the Flexor brevis pollicis
muscles; the remaining muscles of this group being supplied by the ulnar nerve.
The digital branches are five in number. The first and second pass along
the borders of the thumb, the most external one communicating with branches of
the radial nerve. The third passes along the radial side of the index finger, and
supplies the first Lumbrical muscle. Th.Q fourth subdivides to supply the adjacent
512
SPINAL NERVES.
265. — Nerves of the Left Upper Extremity. Front View.
EotrtefnaT
'Anterlo r niofcccio
fnte r-na 7
'Anterior T/ionncte
]\Ttcsfiulo-
Cntctnec u-a
ULNAR.
513
sides of the index and middle fingers, and sends a branch to the second Lumbri-
cal muscle. The fifth supplies the adjacent sides of the middle and ring fingers,
and communicates with a branch from the ulnar nerve.
Each digital nerve, opposite the base of the first phalanx, gives off a dorsal
branch, which joins the dorsal digital nerve, and runs along the side of the
dorsum of the finger, ending in the integument over the last phalanx. At the
end of the finger, the digital nerve divides into a palmar and a dorsal branch; the
former supplies the extremity of the finger, and the latter ramifies around and
beneath the nail. The digital nerves, as they run along the fingers, are placed
superficial to the digital arteries.
The Ulnar Nerve is placed along the inner or ulnar side of the upper limb,
and is distributed to the muscles and integument of the fore-arm and hand. It
is smaller than the median, behind which it is placed, diverging from it in its
course down the arm. It arises from the inner cord of the brachial plexus, in
common with the internal head of the median and the internal cutaneous nerves.
At its commencement, it lies at the inner side of the axillary artery, and holds
the same relation with the brachial artery to the middle of the arm. From this
point, it runs obliquely across the internal head of the Triceps, pierces the internal
intermuscular septum, and descends to the groove between the internal condyle
and olecranon, accompanied by the inferior profunda artery. At the elbow, it
rests upon the inner condyle, and passes into the fore-arm between the two heads
of the Flexor carpi ulnaris. In the fore-arm, it descends in a perfectly straight
course along its ulnar side, lying upon the Flexor profundus digitorum, its upper
half being covered by the Flexor carpi ulnaris, its lower half lying on the outer
side of this muscle, covered by the integument and fascia. The ulnar artery,
in the upper part of its course, is separated from the ulnar nerve by a consider-
able interval; in the lower half of its course, the nerve lies to its inner side.
At the lorist, the ulnar nerve crosses the annular ligament on the outer side of
the pisiform bone, a little behind the ulnar artery, and immediately beyond this
bone divides into two branches, superficial and deep palmar.
The branches of the ulnar nerve are
Articular (elbow).
Muscular. T Ti 1 1 Superficial palmar.
In fore-arm <^ Cutaneous. | Deep palmar.
Dorsal branch.
Articular (wrist).
The Articular branches distributed to the elbow-joint consist of several small
filaments. They arise from the nerve as it lies in the groove between the inner
condyle and olecranon.
The Muscular branches are two in number; one supplying the Flexor carpi
ulnaris; the other, the inner half of the Flexor profundus digitorum. They
arise from the trunk of the nerve near the elbow.
The Cutaneous branch arises from the ulnar nerve about the middle of the
fore-arm, and divides into a superficial and deep branch.
The superficial branch (frequently absent) pierces the deep fascia near the
wrist, and is distributed to the integument, communicating with a branch of the
internal cutaneous nerve.
The deep branch lies on the ulnar artery, which it accompanies to the hand,
some filaments entwining around the vessel, which end in the integument of the
palm, communicating with branches of the median nerve.
The Dorsal cutaneous branch arises about two inches above the wrist; it
passes backwards beneath the Flexor carpi ulnaris, perforates the deep fascia, and
running along the ulnar side of the wrist and hand, supplies the inner side of the
little finger, and the adjoining sides of the little and ring fingers; it also sends a
communicating filament to that branch of the radial nerve which supplies the
adjoining sides of the middle and ring fingers.
LL
5'4
SPINAL NERVES.
Articular filaments to the wrist are also supplied by the ulnar nerve.
The Superficial palmar branch supplies the Palmaris brevis, and the integument
on the inner side of the hand, and terminates in two digital branches, which are
distributed, one to the ulnar side of the little finger, the other to the adjoining
sides of the little and ring fingers, the latter communicating with a branch from
the median.
The Deep palmar branch passes between the Abductor and Flexor brevis
minimi digiti muscles, and follows the course of the deep palmar arch beneath
the fiexor tendons. At
266, — The Supra-Scapular, Circumflex, and Musculo-Spiral
Nerves.
SuprciScajpular
te rio r-lnte rcsseoUfJ
its origin, it supplies the
muscles of the little finger.
As it crosses the deep part
of the hand it sends two
branches to each interos-
seous space, one for the
Dorsal and one for the
Palmar interosseous mus-
cle, the branches to the
second and third Palmar
interossei supplying fila-
ments to the two inner
Lumbrical muscles. At its
termination between the
thumb and index finger, it
supplies the Adductor pol-
licis and the inner head of
the Flexor brevis pollicis.
The Musculo-Spiral
Nerve (fig.266),the largest
branch of the brachial
plexus, supplies the mus-
cles of the back part of the
arm and fore-arm, and the
integument of the same
parts, as well as that of
the hand. It arises from
the posterior cord of the
brachial plexus by a com-
mon trunk with the cir-
cumflex nerve. At its
commencement, it is placed
behind the axillary and
upper part of the brachial
arteries, passing down in
front of the tendons of the
Latissimus dorsi and Teres
major. It winds round
the humerus in the spiral
groove with the superior
profunda artery and vein,
passing from the inner to
the outer side of the bone,
beneath the Triceps mus-
cle. At the outer side of
the arm, it descends be-
tween the Brachialis an-
ticus and Supinator longus
MUSCULO- SPIRAL.
515
to the front of the external condyle, where it divides into the radial and posterior
interosseous nerves.
The branches of the musculo -spiral nerve are:
Muscular. Radial.
Cutaneous. Posterior interosseous.
The Muscular branches supply the Triceps, Anconeus, Supinator longus,
Extensor carpi radialis longior, and Brachialis anticus. These branches are
derived from the nerve, at the inner side, back part, and outer side of the
arm.
The internal muscular branches supply the inner and middle heads of the
Triceps muscle. That to the inner head of the Triceps, is a long, slender
filament, which lies' close to the ulnar nerve, as far as the lower third of the
arm.
The posterior muscular branch, of large size, arises from the nerve in the
groove between the Triceps and the humerus. It divides into branches which
supply the outer head of the Triceps and Anconeus muscles. The branch for the
latter muscle is a long, slender filament, which descends in the substance of the
Triceps to the Anconeus.
The external muscular branches supply the Supinator longus. Extensor carpi
radialis longior, and Brachialis anticus.
The Cutaneous branches are three in number, one internal, and two external.
The internal cutaneous branch arises in the axillary space, with the inner
muscular branch. It is of small size, and passes across the axilla to the inner
side of the arm, supplying the integument on its posterior aspect nearly as far as
the olecranon.
The two external cutaneous branches perforate the outer head of the Triceps,
at its attachment to the humerus. The upper and smaller one follows the course
of the cephalic vein to the front of the elbow, supplying the integument of the
lower half of the upper arm on its anterior aspect. The lower branch pierces the
deep fascia below the insertion of the Deltoid, and passes down along the outer
side of the arm and elbow, and along the radial side of the fore-arm to the wrist,
supplying the integument in its course, and joining, near its termination, with a
branch of the external cutaneous nerve.
The Radial Nerve passes along the front of the radial side of the fore-arm, to
the commencement of its lower third. It lies at first a little to the outer side of
the radial artery, concealed beneath the Supinator longus. In the middle third
of the fore-arm, it lies beneath the same muscle, in close relation with the outer
side of that vessel. It quits the artery about three inches above the wrist, passes
beneath the tendon of the Supinator longus, and, piercing the deep fascia at the
outer border of the fore-arm, divides into two branches.
The external branch, the smaller of the two, supplies the integument of the
radial side, and ball of the thumb, joining with the posterior branch of the ex-
ternal cutaneous nerve.
The internal branch communicates, above the wrist, with a branch from the
external cutaneous, and, on the back of the hand, forms an arch with the dorsal
branch of the ulnar nerve. It then divides into digital nerves, which supply,
the first, the ulnar side of the thumb; the second, the radial side of the index
finger; the third, the adjoining sides of the index and middle fingers; and the
fourth, the adjacent borders of the middle and ring fingers. The latter nerve
communicates with a filament from the dorsal branch of the ulnar nerve.
The Posterior Interosseous Nerve pierces the Supinator brevis, winds to the
back of the fore-arm, in the substance of this muscle, and, emerging from its
lower border, passes down between the superficial and deep layer of muscles, to
the middle of the fore-arm. Considerably diminished in size, it descends on the
interosseous membrane, beneath the Extensor secundi internodii pollicis, to the
back of the carpus, where it presents a gangliform enlargement, from which
L L 2
5i6 SPINAL NEEVES.
filaments are distributed to the ligaments and articulations of the carpus. It
supplies all the muscles of the radial and posterior brachial regions, excepting
the Anconeus, Supinator longus, and Extensor carpi radialis longior.
Dorsal Nerves.
The Dorsal Nerves are twelve in number on each side. The first appears
between the first and second dorsal vertebrae, and the last between the last dorsal
and first lumbar.
The roots of origin of the dorsal nerves are few in number, of small size, and
vary but slightly from the second to the last. Both roots are very slender; the
posterior ones exceeding in thickness those of the anterior only in a slight degree.
These roots gradually increase in length from above downwards, and remain in
contact with the spinal cord for a distance equal to the height of, at least, two
vertebras, in the lower part of the dorsal region. They then join in the inter-
vertebral foramen, and, at their exit, divide into two branches, a posterior, or
dorsal, and an anterior, or intercostal branch.
. The first and last dorsal nerves are exceptions to these characters.
The Posterior primary branches of the Dorsal Nerves, which are smaller than
the intercostal, pass backwards between the transverse processes, and divide into
external and internal branches.
The external branches increase in size from above downwards. They pass
through the Longissimus dorsi, corresponding to the cellular interval between it
and the Sacro-lumbalis, supplying these muscles, as well as those by which they
are continued upwards to the head, and the Levatores costarum; the five or six
lower ones giving off cutaneous filaments.
The internal branches of the six upper nerves pass inwards to the interval
between the Multifidus spinae, and Semi-spinalis dorsi muscles, which they
supply; then, piercing the origin of the Rhomboideus and Trapezius, become
cutaneous by the side of the spinous processes. The internal branches of the
six lower nerves are distributed to the Multifidus spin^, without giving off any
cutaneous filaments.
The cutaneous branches of the dorsal nerves are twelve in number, the six
upper being derived from the internal branches, and the six lower from the
external branches. The former pierce the Rhomboid and Trapezius muscles,
close to the spinous processes, and ramify in the integument. They are fre-
quently furnished with gangliform enlargements. The six lower cutaneous
branches pierce the Serratus posticus inferior, and Latissimus dorsi, in a line
with the angles of the ribs.
Intercostal Nerves.
The Intercostal Nerves (anterior primary branches of the dorsal nerves), are
twelve in number on each side. They are distributed to the parietes of the thorax
and abdomen, separately from each other, without being joined in a plexus, in
which respect they differ from all the other spinal nerves. Each nerve is con-
nected with the adjoining ganglia of the sympathetic by one or two filaments.
The intercostal nerves may be divided into, two sets, from the difference they
present in their distribution. The six upper, with the exception of the first,
are limited in their distribution to the parietes of the chest. The six lower
supply the parietes of the chest and abdomen.
Upper Intercostal Nerves.
The Upper Intercostal Nerves pass forwards in the intercostal spaces with the
intercostal vessels, lying below the veins and artery. At the back of the chest,
they lie between the pleura and the External intercostal muscle, but are soon
placed between the two planes of Intercostal muscles as far as the costal car-
INTERCOSTAL.
517
tilages, where they lie between the pleura and the Internal intercostal muscles.
Near the sternum, they cross the internal mammary artery, and Triangularis
sterni, pierce the Internal intercostal and Pectoralis major muscles, and supply
the integument of the mamma and front of the chest, forming the anterior
cutaneous nerves of the thorax; that from the second nerve becoming joined with
the supra-clavicular nerves.
Branches. Numerous slender muscular filaments supply the Intercostal and
Triangularis sterni muscles. Some of these branches, at the front of the chest,
cross the costal cartilages from one to another intercostal space.
Lateral Cutaneous Nerves. These are derived from the intercostal nerves,
midway between the vertebrse and sternum, pierce the External intercostal and
Serratus magnus muscles, and divide into two branches, anterior and posterior.
The anterior branches are reflected forwards to the side and fore part of the
chest, supplying the integument of the chest and mamma, and the upper digita-
tions of the External oblique.
The posterior branches are reflected backwards, to supply the integument over
the scapula and Latissimus dorsi.
The first intercostal nerve has no lateral cutaneous branch. The lateral cuta-
neous branch of the second intercostal nerve is of large size, and named from its
origin and distribution, the intercosto-humeral nerve.
The Intercosto-humeral Nerve is of large size. It pierces the External inter-
costal muscle, crosses the axillary space to the inner side of the arm, and joins
with a filament from the nerve of Wrisberg. It then pierces the fascia, and sup-
plies the integument of the upper half of the inner and posterior side of the arm,
communicating with the internal cutaneous branch of the musculo-spiral nerve.
The size of this nerve is in inverse proportion to the size of the other cutaneous
nerves, especially the nerve of Wrisberg.
Lower Intercostal Nerves.
The Lower Intercostal Nerves (excepting the last) have the same arrangement
as the upper ones as far as the anterior extremities of the intercostal spaces, where
they pass behind the costal cartilages, and between the Internal oblique and
Transversalis muscles, to the sheath of the Rectus, which they perforate. They
supply the Rectus muscle, and terminate in branches which become subcutaneous
near the linea alba (anterior cutaneous nerves of the abdomen), and supply the inte-
gument in front of the abdomen, being directed outwards to the lateral cutaneous
nerves. The lower intercostal nerves supply the Intercostal and Abdominal mus-
cles, and about the middle of their course give off lateral cutaneous branches, which
pierce the External intercostal and External oblique muscles, and are distributed to
the integument of the abdomen, the anterior branches passing nearly as far forAvards
as the margin of the Rectus, the posterior branches passing to supply the skin
over the Latissimus dorsi, where they join the dorsal cutaneous nerves.
Peculiar Dorsal Nerves.
First Dorsal Nerve. Its roots of origin are similar to those of a cervical nerve.
Its posterior or dorsal branch resembles, in its mode of distribution, the dorsal
branches of the cervical nerves. Its anterior branch enters almost wholly into the
formation of the brachial plexus, giving off, before it leaves the thorax, a small
intercostal branch, which runs along the first intercostal space, and terminates on
the front of the chest, by forming the first anterior cutaneous nerve of the thorax.
The first intercostal nerve gives off no lateral cutaneous branch.
' The Last Dorsal is larger than the other dorsal nerves. Its anterior branch
runs along the lower border of the last rib in front of the Quadratus lumborum,
perforates the aponeurosis of the Transversalis, and passes forwards between it
and the Internal oblique, to be distributed in the same manner as the preceding
nerves. It communicates with the ilio-hypogastric brancli of the lumbar plexus,
5i8 SPINAL NERVES.
and is occasionally connected with the first lumbar nerve by a slender branch, the
dorsi-lumbar nerve, which descends in the substance of the Quadratus lumboruna.
The lateral cutaneous branch of the last dorsal is remarkable for its large
size; it perforates the Internal and External oblique muscles, passes downwards
over the crest of the ilium, and is distributed to the integument of the front of
the hip, some of its filaments extending as low down as the trochanter major.
Lumbar Nerves.
The Lumbar Nerves are five in number on each side; the first appeafs between
the first and second lumbar vertebras, and the last between the last lumbar and the
base of the sacrum.
The roots of the lumbar nerves are the largest, and their filaments the most
numerous, of all the spinal nerves, and they are closely aggregated together upon
the lower end of the cord. The anterior roots are smaller, but there is not
the same disproportion between them and the posterior roots as in the cervical
nerves. The roots of these nerves have a vertical direction, and are of consider-
able length, more especially the lower ones, as the spinal cord does not extend
beyond the first lumbar vertebra. The roots become joined in the intervertebral
foramina, and at their exit divide into two branches, anterior and posterior.
The Posterior branches of the lumbar nerves diminish in size from above down-
wards; they pass backwards between the transverse processes, and divide into
external and internal branches.
The external branches supply the Erector spinge and Intertransverse muscles.
From the three upper branches cutaneous nerves are derived, which pierce the
Sacro-lumbalis and Latissimus dorsi muscles, and descend over the back part of
the crest of the ilium to be distributed to the -integument of the gluteal region,
some of the filaments passing as far as the trochanter major.
The internal branches, the smaller, pass inwards close to the articular processes
of the vertebra?, and sujiply the Multifidus spinee and Inter- spinales muscles.
The Anterior branches of the lumbar nerves increase in size from above down-
wards. At their origin, they communicate with the lumbar ganglia of the sympa-
thetic by long slender filaments, which accompany the lumbar arteries around the
sides of the bodies of the vertebras, beneath the Psoas muscle. The nerves pass
obliquely outwards behind the Psoas magnus, or between its fasciculi, distributing
filaments to it and the Quadratus lumborum. The anterior branches of the four
upper nerves are connected together in this situation by anastomotic loops, and
form the lumbar plexus. The anterior branch of the fifth lumbar, joined with a
branch from the fourth, descends across the base of the sacrum to join the ante-
rior branch of the first sacral nerve, and assist in the foi-mation of the sacral
plexus. The cord resulting from the union of these two nerves is called the
lumbo-sacral nerve.
Lumbar Plexus.
The Lumbar Plexus is formed by the loops of communication between the
anterior branches of the four upper lumbar nerves. The plexus is narrow above,
and occasionally connected with the last dorsal by a slender branch, the dorsi
lumbar nerve; it is broad below, where it is joined to the sacral plexus by the
lumbo-sacral. It is situated in the substance of the Psoas muscle near its poste-
rior part, in front of the transverse processes of the lumbar vertebrae.
The mode in which the plexus is formed is the following. The first lumbar
nerve gives off the ilio-hypogastric and ilio-inguinal nerves, and a communicating
branch to the second. The second gives off the external cutaneous and genito-
crural, and a communicating branch to the third nerve. The third nerve gives
a descending filament to the fourth, and divides into two branches, which assist
in forming the anterior crural and obturator nerves. The fourth nerve completes
the formation of the anterior crural, and the obturator; furnishes part of the
accessory obturator, and gives off a communicating branch to the fifth lumbar.
LUMBAR PLEXUS.
519
The branches of the lumbar plexus are the
Ilio-hypogastric.
Ilio-inguinal.
Genito- crural.
External cutaneous.
Obturator.
Accessory obturator.
Anterior crural.
These branches may be divided into two groups, according to their mode of
distribution. One group, including the ilio-hypogastric, ilio-inguinal, and part
of the genito-crural nerves, supplies the lower part of the parietes of the abdo-
men; the other group, which includes the remaining nerves, supplies the fore
part of the thigh and inner side of the leg.
■2.^']. — The Lumbar Plexus and its Branches.
The Ilio-hypogastric branch {superior musculo-cufaneous) arises from the
first lumbar nerve. It pierces the outer border of the Psoas muscle at its upper part,
and crosses obliquely over the Quadratus lumborum to the crest of the ilium. It
then perforates the Transversalis muscle, and divides between it and the Internal
oblique into two branches, iliac and hypogastric.
The iliac branch pierces the Internal and External oblique muscles imme-
diately above the crest of the ilium, and is distributed to the integument of the
gluteal region, behind the lateral cutaneous branch of the last dorsal nerve (fig. 270).
The size of this nerve bears an inverse proportion to that of the cutaneous branch
of the last dorsal nerve.
520 SPINAL NERVES.
The hypogastric branch continues onwards between the Internal oblique and
Transversalis muscles. It first pierces the Internal oblique, and near the middle
line perforates the External oblique, and is distributed to the integument covering
the hypogastric region.
The Ilio-inguinal branch {inferior musculo-cutaneous), smaller than the
preceding, also arises from the first lumbar nerve. It pierces the outer border of
the Psoas just below the ilio-hypogastric, and passes obliquely downwards and
outwards across the Quadratus lumborum and Iliacus muscles, perforates the
Transversalis, and communicates with the ilio-hypogastric nerve between that
muscle and the Internal oblique, near the fore part of the crest of the ilium. The
nerve then pierces the Internal oblique, distributing filaments to it, and accom-
panying the spermatic cord, escapes at the external abdominal ring, and is distri-
buted to the integument of the scrotum and upper and inner part of the thigh in
the male, and to the labium in the female. The size of this nerve is in inverse
proportion to that of the ilio-hypogastric. Occasionally it is very small, and
ends by joining it; in such cases, a branch from the ilio-hypogastric takes the
place of that nerve, or the nerve may be altogether absent.
The Genito-crural Nerve arises from the second lumbar, and by a few fibres
from the cord of communication between it and the first. It passes obliquely
through the substance of the Psoas, descends on its surface to near Poupart's
ligament, and divides into a genital and a crural branch.
The genital branch descends on the external iliac artery, sending a few fila-
ments around that vessel; it then pierces the fascia transversalis, and passing
through the internal abdominal ring, descends along the back part of the sper-
matic cord to the scrotum, and supplies, in the male, the Cremaster muscle. In
the female, it accompanies the round ligament, and is lost upon it.
The crural branch passes along the inner margin of the Psoas muscle, beneath
Poupart's ligament, into the thigh, where it pierces the fascia lata, and is distri-
buted to the integument of the upper and anterior aspect of the thigh, communi-
cating with the middle cutaneous nerve.
A few filaments from this nerve may be traced on to the femoral artery; they
are derived from the nerve as it passes beneath Poupart's ligament.
The External Cutaneous Nerve arises from the second lumbar, or from the
loop between it and the third. It perforates the outer border of the Psoas muscle
about its middle, and crosses the Iliacus muscle obliquely, to the notch imme-
diately beneath the anterior superior spine of the ilium, where it passes beneath
Poupart's ligament into the thigh, and divides into two branches of nearly equal
size, anterior and posterior.
The anterior branch descends in an aponeurotic canal formed in the fascia
lata, becomes superficial about four inches below Poupart's ligament, and divides
into branches, which are distributed to the integument along the anterior and
outer part of the thigh, as far down as the knee. This nerve occasionally com-
municates with the long saphenous nerve.
The posterior branch pierces the fascia lata, and subdivides into branches
which pass across the outer and posterior surface of the thigh, supplying the
integument in this region as far as the middle of the thigh.
The Obturator Nerve supplies the Obturator externus and Adductor muscles
of the thigh, the articulations of the hip and knee, and occasionally the integu-
ment of the thigh and leg. It arises by two branches; one from the third, the
other from the fourth lumbar nerve. It descends through the inner fibres of the
Psoas muscle, and emerges from its inner border near the brim of the pelvis; it
then runs along the lateral wall of the pelvis, above the obturator vessels, to the
upper part of the obturator foramen, where it enters the thigh, and divides into
an anterior and a posterior branch, separated by the Adductor brevis muscle.
The anterior branch passes down in front of the Adductor brevis, being
covered by the Pectineus and Adductor longus; and at the lower border of the
latter muscle, communicates with the internal cutaneous and internal saphenous
CUTANEOUS NEKVES OF LOWER EXTREMITY.
i68, — Cutaneous Nerves of Lower
Extremity. Front View.
521
269. — Nerves of the Lower Extremity.
Front View.
1/71: X ^^ .
'Ext.SaJikenoas .
.Ant.Tihinl
Anteriof
Criirail
A.nte.T'ioT^Xii vision
of O'btwraio'r
522 SPINAL NERVES.
nerves, forming a kind of plexus. It then descends upon the femoral artery,
upon which it is finally distributed.
This nerve, near the obturator foramen, gives off an articular branch to the
hip-joint. Behind the Pectineus, it distributes muscular branches to the Adduc-
tor longus and Gracilis, and occasionally to the Adductor brevis and Pectineus,
and receives a communicating branch from the accessory obturator nerve.
Occasionally this communicating branch is continued down, as a cutaneous branch,
to the thigh and leg; emerging from the lower border of the Adductor longus, it
descends along the posterior margin of the Sartorius to the inner side of the knee,
where it pierces the deep fascia, communicates with the long saphenous nerve,
and is distributed to the integument of the inner side of the leg, as low down as
its middle. When this branch is small, its place is supplied by the internal
cutaneous nerve.
The posterior branch of the obturator nerve pierces the Obturator externus,
and passes behind the Adductor brevis to the front of the Adductor magnus,
where it divides into numerous muscular branches, which supply the Obturator
externus, the Adductor magnus, and occasionally the Adductor brevis.
The articular branch for the knee-joint perforates the lower part of the
Adductor magnus, and enters the upper part of the popliteal space; descending
upon the popliteal artery, as far as the back part of the knee-joint, it perforates
the posterior ligament, and is distributed to the synovial membrane. It gives
filaments to the artei'y in its course.
The Accessory Obturator Nerve is of small size, and arises either from the
obturator nerve near its origin, or by separate filaments from the third and fourth
lumbar nerves. It descends along the inner border of the Psoas muscle, crosses
the body of the pubes, and passes beneath the Pectineus muscle, where it divides
into numerous branches. One of these supplies the Pectineus, penetrating its
under surface; another is distributed to the hip-joint; while a third communicates
with the anterior branch of the obturator nerve. This branch, when of large
size, is prolonged (as already mentioned), as a cutaneous branch, to the leg. The
accessory obturator nerve is not constantly found; when absent, the hip-joint
receives branches from the obturator nerve. Occasionally it is very small, and
becomes lost in the capsule of the hip-joint.
The Anterior Crural Nerve is the largest branch of the lumbar plexus. It
supplies muscular branches to the Iliacus, Pectineus, and all the muscles on the
front of the thigh, excepting the Tensor vaginae femoris; cutaneous filaments to
the front and inner side of the thigh, and to the leg and foot; and articular branches
to the knee. It arises from the third and fourth lumbar nerves, receiving also a
fasciculus from the second. It descends through the fibres of the Psoas muscle,
emerging from it at the lower part of its outer border; and passes down between
it and the Iliacus, and beneath Poupart's ligament, into the thigh, where it
becomes somewhat flattened, and divides into an anterior or cutaneous, and a
posterior or muscular part. Beneath Poupart's ligament, it is separated from the
femoral artery by the Psoas muscle, and lies beneath the iliac fascia.
Within the pelvis, the anterior crural nerve gives off some small branches to
the Iliacus, and a branch to the femoral artery, which is distributed upon the
upper part of that vessel. The origin of this branch varies; it occasionally
arises higher than usual, or it may arise lower down in the thigh.
External to the pelvis, the following branches are given off :
From the Anterior Division. From the Posterior Division.
Middle cutaneous. Muscular.
Internal cutaneous. Articular.
Long Saphenous.
The Middle Cutaneous Nerve pierces the fascia lata (occasionally the Sarto-
rius also), about three inches below Poupart's ligament, and divides into two
branches, which descend in immediate proximity along the fore part of the thigh,
ANTERIOR CRURAL. 523
distributing numerous branches to the integument as low as the front of the knee,
where it joins a bi-anch of the internal saphenous nerve. Its outer branch com-
municates, above, with the crural branch of the genito-crural nerve; and the inner
branch with the internal cutaneous nerve below. The Sartorius muscle is sup-
plied by this or the following nerve.
The Internal Cutaneous Nerve passes obliquely across the upper part of the
sheath of the femoral artery, and divides in front, or at the inner side, of that
vessel, into two branches, anterior and internal.
The anterior branch perforates the fascia lata at the lower third of the thigh,
and divides into two branches, one of which supplies the integument as low down
as the inner side of the knee; the other crosses the patella to the outer side of
the joint, communicating in its course with the long saphenous nerve. A cuta-
neous filament is occasionally given off from this nerve, which accompanies the
long saphenous vein; and it sometimes communicates with the internal branch of
the nerve.
The inner branch descends along the posterior border of the Sartorius muscle
to the knee, where it pierces the fascia lata, communicates with the long saphe-
nous nerve, and gives off several cutaneous branches. The nerve then passes
down the inner side of the leg, to the integument of which it is distributed. This
nerve, beneath the fascia lata, joins in a plexiform network, by uniting with
branches of the long saphenous and obturator nerves. When the communicating
branch from the latter nerve is large, and continued to the integument of the leg,
the inner branch of the internal cutaneous is small, and terminates at the plexus,
occasionally giving off a feAV cutaneous filaments.
This nerve, before subdividing, gives off a few filaments, which pierce the
fascia lata, to supply the integument of the inner side of the thigh, accompanying
the long saphena vein. One of these filaments passes through the saphenous
opening; a second becomes subcutaneous about the middle of the thigh; and a third
pierces the fascia at its lower third.
The Long, or Internal Sajjhenoiis Nerve, is the largest of the cutaneous
branches of the anterior crural nerve. It approaches the femoral artery where
this vessel passes beneath the Sartorius, and lies on its outer side, beneath the
aponeurotic covering, as far as the opening in the lower part of the Adductor
magnus. It then quits the artery, and descends vertically along the inner side of
the knee, beneath the Sartorius, pierces the deep fascia between the tendons of
the Sartorius and Gracilis, and becomes subcutaneous. The nerve then passes
along the inner side of the leg, accompanied by the internal saphenous vein,
descends behind the internal border of the tibia, and, at the lower third of the leg,
divides into two branches: one continues its course along the margin of the tibia,
terminating at the inner ankle; the other passes in front of the ankle, and is dis-
tributed to the integument along the inner side of the foot, as far as the great toe.
Branches. The long saphenous nerve, about the middle of the thigh, gives off
a communicating branch, which joins the plexus formed by the obturator and
internal cutaneous nerves.
At the inner side of the hnee, it gives off a large branch {n. cutaneus patellce),
which pierces the Sartorius and fascia lata, and is distributed to the integument
in front of the patella. This nerve communicates above the knee with the
anterior branch of the internal cutaneous; below the knee, with other branches of
the long saphenous; and, on the outer side of the joint, with branches of the
middle and external cutaneous nerves, forming a plexiform network, the plexus
patellae. This nerve is occasionally small, and terminates by joining the internal
cutaneous, which supplies its place in front of the knee.
Beloio the knee, the branches of the long saphenous nerve are distributed to
the integument of the front and inner side of the leg, communicating with the
cutaneous branches from the internal cutaneous, or obturator nerve.
The Deep Group of branches of the anterior crural nerve are muscular and
articular.
524 SPINAL NERVES.
The Muscular branches supply the Pectineus, and all the muscles on the front
of the thigh, except the Tensor vaginas femoris, which is supplied from the
gluteal nerve, and the Sartorius, which is supplied by filaments from the middle
or internal cutaneous nerves.
The branches to the Pectineus, usually two in number, pass inwards )3ehind
the femoral vessels, and enter the muscle on its anterior surface.
The branch to the Rectus muscle enters its under surface high up.
The branch to the Vastus externus, of large size, follows the course of the
descending branch of the external circumflex artery, to the lower part of the
muscle. It gives off an articular filament.
The branches to the Vastus internus and crureus, enter the middle of those
muscles.
The Articular branches, two in number, supply the knee-joint. One, a long,
slender filament, is derived from the nerve to the Vastus externus. It penetrates
the capsular ligament of the joint on its anterior aspect. The other is derived
from the nerve to the' Vastus internus. It descends along the internal inter-
muscular septum, accompanying the deep branch of the anastomotica magna,
pierces the capsular ligament of the joint on its inner side, and supplies the
synovial membrane.
The Sacral and Coccygeal Nerves.
The Sacral Nerves are five in number on each side. The four upper ones pass
from the sacral canal, through the sacral foramina; the fifth escaping with the
coccygeal nerve, from the sacral canal at its termination.
The roots of origin of the upper sacral (and lumbar) nerves, are the largest of
all the spinal nerves; whilst those of the lowest sacral and coccygeal nerve are
the smallest.
The length of the roots of these nerves is very considerable, being longer than
those of any of the other spinal nerves, on account of the spinal cord not extend-
ing beyond the first lumbar vertebra. From their great length, and the appear-
ance they present in connection with the spinal cord, the roots of origin of these
nerves are called collectively the cauda equina. Each sacral and coccygeal nerve
divides into two branches, anterior and posterior.
The Posterior Sacral Nerves are small, diminish in size from above downwards,
and emerge, except the last, from the sacrum by the posterior sacral foramina.
The three upper ones are covered, at their exit from the sacrum, by the Multi-
fidus spinas, and divide into external and internal branches.
The internal branches are small, and supply the Multifidus spinse.
The external branches communicate with one another, and with the last lumbar
and fourth sacral nerves, by means of anastomosing loops. These branches pass
outwards, to the outer surface of the great sacro- sciatic ligament, where they
form a second series of loops beneath the Gluteus maximus. Cutaneous branches
from these second series of loops, iisually three in number, pierce this muscle,
one near the posterior inferior spine of the ilium; another opposite the end of the
sacrum; and the third, midway between these two. They supply the integument
over the posterior part of the gluteal region.
The two loiver posterior Sacral Nerves are situated below the Multifidus spinse^
They are of small size, and join with each other, and with the coccygeal nerve, so
as to form loops on the back of the sacrum, filaments from which supply the
integument over the coccyx.
The posterior branch of the Coccygeal Nerve is small. It separates from the
anterior in the sacral canal, and receives, as already mentioned, a communicating
branch from the last sacral. It is lost in the fibrous structure on the back of the
coccyx.
The Anterior Sacral Nerves diminish in size from above downwards. The
four upper ones emerge from the anterior sacral foramina; the anterior branch of
the fifth, together with the coccygeal nerve, between the sacrum and the coccyx.
SACRAL PLEXUS. 525
All the anterior sacral nerves communicate with the sacral ganglia of the sympa-
thetic, at their exit from the sacral foramina. The^r^^ nerve, of large size, unites
with the lumbo-sacral nerve. The second equals in size the preceding, with which
it joins. The third, about one-fourth the size of the second, unites with the
preceding nerves, to form the sacral plexus.
Th.Q fourth anterior Sacral Nerve sends a branch to join the sacral plexus.
The remaining portion of the nerve divides into visceral and muscular branches:
and a communicating filament descends to join the fifth sacral nerve. The visceral
branches are distributed to the viscera of the pelvis, communicating with the sym-
pathetic nerve. These branches ascend upon the rectum and bladder: in the
female, upon the vagina and bladder, communicating with branches of the sympa-
thetic to form the hypogastric plexus. The muscular branches are distributed to
the Levator ani, Coccygeus, and Sphincter ani. Cutaneous filaments arise from
the latter branch, which supply the integument between the anus and coccyx.
Th.Q fifth anterior Sacral Nerve, after passing from the lower end of the sacral
canal, pierces the Coccygeus muscle, and descends upon its anterior surface to the
tip of the Coccyx, where it perforates that muscle, to be distributed to the integu-
ment over the back part and side of the Coccyx. This nerve communicates
above with the fourth, and below with the coccygeal nerve, and supplies the
Coccygeus muscle.
The anterior branch of the coccygeal nerve is a delicate filament which escapes
at the termination of the sacral canal. It pierces the sacro-sciatic ligament and
Coccygeus muscle, is joined by a branch from the fifth anterior sacral, and be-
comes lost in the integument at the back part and side of the Coccyx.
Sackal Plexus.
The sacral plexus is formed by the lumbo-sacral, the anterior branches of the
three upper, and part of the fourth sacral nerves. These nerves proceed in
different directions; the upper ones obliquely outwards, the lower ones nearly
horizontally, and unite into a single, broad, flat cord. The sacral plexus is tri-
angular in form, its base corresponding with the exit of the nerves from the
sacrum, its apex with the lower part of the great sacro-sciatic foramen. It rests
upon the anterior surface of the Pyriformis, and is covered in front by the pelvic
fascia, which separates it from the sciatic and pudic branches of the internal iliac
artery, and from the viscera of the pelvis.
The branches of the sacral plexus are:
Muscular. Pudic.
Superior gluteal. Small sciatic.
Great sciatic.
The Muscular branches supply the Pyriformis, Obturator Internus, the two Ge-
melli, and the Quadratus femoris. The branch to the Pyriformis arises either from
the plexus, or from the upper sacral nerves: the branch to the Obturator internus
arises at the junction of the lumbo-sacral and first sacral nerves; it crosses behind
the spine of the ischium, and passes through the lesser sacro-sciatic foramen to
the inner surface of the Obturator internus: the branch to the Gemellus superior
arises from the lower part of the plexus, near the pudic nerve: the small branch
to the Gemellus inferior and Quadratus femoris also arises from the lower part of
the plexus; it passes beneath the Gemelli and tendon of the Obturator internus,
and supplies an articular branch to the hip-joint. This branch is occasionally
derived from the upper part of the great sciatic nerve.
The Superior Gluteal Nerve arises from the back part of the lumbo-sacral;
it passes from the pelvis through the great sacro-sciatic foramen above the Pyri-
formis muscle, accompanied by the gluteal artery, and divides into a superior and
an inferior branch.
The superior branch follows the line of origin of the Gluteus minimus, and
supplies it and the Gluteus medius.
526 SPINAL NERVES.
The inferior branch crosses obliquely between the Gluteus minimus and me-
dius, distributing filaments to both these muscles, and terminates in the Tensor
vaginge femoris, extending nearly to its lower end.
The PuDic Nerve arises from the lower part of the sacral plexus, and leaves
the pelvis, through the great sacro-sciatic foramen, below the Pyriformis. It
then crosses the spine of the ischium, and re-enters the pelvis through the lesser
sacro-sciatic foramen. It accompanies the pudic artery upwards and forwards
along the outer wall of the ischio-rectal fossa, being covered by the obturator
fascia, and divides into two terminal branches, the perineal nerve, and the dorsal
nerve of the penis. Near its origin, it gives off the inferior hgemori'hoidal nerve.
The Inferior Hcemorrhoidal Nerve is occasionally derived from the sacral
plexus. It passes across the ischio-rectal fossa, with its accompanying vessels,
towards the lower end of the rectum, and is distributed to the External sphincter
and the integument around the anus. Branches of this nerve communicate with
the inferior pudendal and superficial perineal nerves on the inner margin of the
thigh.
The Perineal Nerve, the most inferior and largest of the two terminal branches
of the pudic, is situated below the pudic artery. It accompanies the superficial
perineal artery in the perineum, dividing into cutaneous and muscular branches.
The cutaneous branches (superficial perineal) are two in number, posterior and
anterior. The posterior branch passes to the back part of the ischio-rectal fossa,
distributing filaments to the Sphincter ani and integument in front of the anus,
which communicate with the inferior hasmorrhoidal nerve; it then passes for-
wards, with the anterior branch, to the back of the scrotum, communicating with
this nerve and the inferior pudendal. The anterior branch passes to the fore
part of the ischio-rectal fossa, in front of the preceding, and accompanies it to the
scrotum and under part of the penis. This branch gives one or two filaments to
the Levator ani.
The muscular branches are distributed to the Transversus perinei. Accelerator
urinae, Erector penis, and Compressor urethra. The nerve of the bulb supplies
the corpus spongiosum; some of its filaments run for some distance on the surface,
before penetrating its interior.
The Dorsal Nerve of the Penis is the superior division of the pudic nerve;
it accompanies the pudic artery along the ramus of the ischium, and between
the two layers of the deep perineal fascia; it then pierces the suspensory liga-
ment of the penis, and accompanies the arteria dorsalis penis to the glans, to
which it is distributed. On the penis, this nerve gives. off a cutaneous branch,
which runs along the side of the organ; it is joined with branches of the sympa-
thetic, and supplies the integument of the upper surface and sides of the penis
and prepuce, giving a large branch to the corpus cavernosum.
In the female, the pudic nerve is distributed to the parts analogous to those of
the male ; its superior division terminating in the clitoris, the inferior in the
external labia and perineum.
The Small Sciatic Nerve supplies the integument of the perineum and back
part of the thigh and leg, and one muscle, the Gluteus maximus. It is usually
formed by the union of two branches, which arise from the lower part of the
sacral plexus. It arises below the Pyriformis muscle, descends beneath the Glu-
teus maximus with the sciatic artery, and at the lower border of that muscle
passes along the back part of the thigh, beneath the fascia lata, to the lower
part of the popliteal region, where it pierces the fascia and becomes cutaneous.
It then accompanies the external saphenous vein below the middle of the leg,
its terminal filaments communicating with the external saphenous nerve.
The branches of the small sciatic nerve are muscular (inferior gluteal) and
cutaneous.
The inferior gluteal consist of several large branches given off to the under
surface of the Gluteus maximus, near its lower part.
The cutaneous branches consist of two groups; internal and ascending.
270- — Cutaneous Nerves of Lower
Extremity. Posterior View.
lb «
SCIATIC.
271. — Nerves of the Lower Extremity.
Posterior View.
527
Pudic
X.to OBTURATOR INT,
^'K'iuXl Sccafic
Commnnlcnns
Externul
I' op Jiteal , or
I'ero nea 1/
CoTnmuntcans
J'eronee
fin ntar
528 SPINAL NERVES.
The internal cutaneous branches are distributed to the skin at the upper and
inner side of the thigh, on its posterior aspect. One branch longer than the rest,
the inferior pudendal, curves forward below the tuber ischii, pierces the fascia
lata on the outer side of the ramus of that bone, and is distributed to the integu-
ment of the scrotum, communicating with the superficial perineal nerve.
The ascending cutaneous branches consist of two or three filaments, which
turn upwards round the lower border of the Grluteus maximus, to supply the
integument covering its surface. One or two filaments occasionally descend
along the outer side of the thigh, supplying the integument as far as the middle
of this region.
Two or three branches are given ofi" from the lesser sciatic nerve as it descends
beneath the fascia of the thigh; they supply the integument of the back part of
the thigh, popliteal region, and upper part of the leg.
The G-REAT Sciatic Nerve supplies nearly the whole of the integument of
the leg, the muscles of the back of the thigh, and of the leg and foot. It is the
largest nervous cord in the body, measuring three-quarters of an inch in breadth,
and is the continuation of the lower part of the sacral plexus. It passes out
of. the pelvis through the great sacro-sciatic foramen, below the Pyriformis
muscle. It descends between the trochanter major and tuberosity of the ischium,
along the back part of the thigh, to about its lower third, where it divides into
two large branches, the internal and external popliteal nerves.
This division may take place at any point between the sacral plexus and the
lower third of the thigh. When the division occurs at the plexus, the two nerves
descend together, side by side; or they may be separated, at their commencement,
by the interposition of part or the whole of the Pyriformis muscle. As the nerve
descends along the back of the thigh, it rests at first upon the External rotator
muscles, together with the small sciatic nerve and artery, being covered by the
Gluteus maximus; lower down, it lies upon the Adductor magnus, being covered
by the long head of the Biceps.
The branches of the nerve, before its division, are articular and muscular.
The articular branches arise from the upper part of the nerve; they supply
the hip-joint, perforating its fibrous capsule posteriorly. These branches are
sometimes derived from the sacral plexus.
The muscular branches are distributed to the Flexors of the leg, viz. the
Biceps, Semi-tendinosus and Semi-membranosus, and a branch to the Adductor
magnus. These branches are given ofi* beneath the Biceps muscle.
The Internal Popliteal Nerve, the larger of the two terminal branches of
the great sciatic nerve, descends along the back part of the thigh through the
middle of the popliteal space, to the lower part of the Popliteus muscle, where it
passes with the artery beneath the arch of the Soleus, and becomes the posterior
tibial. It lies at first very superficial, and at the outer side of the popliteal artery;
opposite the knee-joint it is in close relation with these vessels, and crosses the
artery to its inner side.
The branches of this nerve are articular, muscular, and a cutaneous branch,
the external or short saphenous nerve.
The articular branches, usually three in number, supply the knee-joint; two of
these branches accompany the superior and inferior internal articular arteries, and
a third the azygos.
The muscular branches, four or five in number, arise from the nerve as it lies
between the two heads of the Gastrocnemius muscle; they supply this muscle,
the Plantaris, Soleus, and Popliteus.
The External or Short Saphenous Nerve descends between the two heads of
the Gastrocnemius muscle, and about the middle of the back of the leg pierces
the deep fascia, and receives a communicating branch (communicans peronei) from
the external popliteal nerve. The nerve then continues its course down the leg
near the outer margin of the tendo Achillis, in company with the external saphe-
nous vein, winds round the outer malleolus, and is distributed to the integument
PLANTAR.
529
372. — The Plantar Nerves.
along the outer side of the foot and little toe, coininunicating on the dorsum of
the foot with the musculo-cutaneous nerve.
The Posterior Tibial Nerve commences at the lower border of the Popliteus
muscle, and passes along the back part of the leg with the posterior tibial vessels
to the interval between the inner malleolus and the heel, where it divides into the
external and internal plantar nerves. It lies upon the deep muscles of the leg,
and is covered by the deep fascia, the superficial muscles, and integument. In
the upper part of its course, it lies to the inner side of the posterior tibial artery;
but it soon crosses that vessel, and lies to its outer side as far as the ankle. In
the lower third of the leg, it is placed parallel with the inner margin of the tendo
Achillis.
The branches of the posterior tibial nerve are muscular and plantar-cutaneous.
The muscular branches arise either separately, or by a common trunk from the
upper part of the nerve. They supply the Tibialis posticus. Flexor longus digi-
torum, and Flexor longus poUicis muscles; the branch to the latter muscle accom-
panies the peroneal artei'y.
The plantar cutaneous branch perforates the internal annular ligament, and
supplies the integument of the heel and inner side of the sole of the foot.
The Internal Plantar Nerve (fig. 272),
the larger of the two terminal branches of
the posterior tibial, accompanies the internal
plantar artery along the inner side of the
foot. From its origin at the inner ankle it
passes forwards between the Abductor pol-
licis and Flexor brevis digitorum, divides
opposite the bases of the metatarsal bones,
into four digital branches, and communi-
cates with the external plantar nerve.
Branches. In its course, the internal plan-
tar nerve gives oW cutaneous branches,which.
pierce the plantar fascia, and supply the
integument of the sole of the foot; muscular
branches, which supply the Abductor pol-
licis and Flexor brevis digitorum; articular
branches to the articulations of the tarsus
and metatarsus; and four digital branches.
These *pierce the plantar fascia in the clefts
between the toes, and are distributed in the
following manner. The first supplies the
inner border of the great toe, and sends a
filament to the Flexor brevis pollicis muscle ;
the second bifurcates to supply the adjacent
sides of the great and second toes, sending
a filament to the first Lumbrical muscle:
the third digital branch supplies the adja-
cent sides of the second and third toes and
the second Lumbrical muscle ; and t\ie fourth
the corresponding sides of the third and
fourth toes. This nerve receives a commu-
nicating branch from the external plantar
nerve. It will be observed that the distribution of these branches is precisely
similar to that of the median. Each digital nerve gives oft" cutaneous and
articular filaments; and opposite the last phalanx sends a dorsal branch, which
supplies the structures around the nail, the continuation of the nerve being dis-
tributed to the ball of the toe.
The External Plantar Nerve, the smaller of the two, completes the nervous
M M
530 SPINAL NERVES.
supply to the structures of the foot, beuig distributed to the little toe and one half
of the fourth, as well as to some of the deep muscles. It passes obliquely for-
wards with the external plantar artery to the outer side of the foot, lying between
the Flexor brevis digitorum and Flexor accessorius; and in the interval between
the former muscle and Abductor minimi digiti, divides into a superficial and deep
branch. Before its division, it supplies the Flexor accessorius and Abductor
minimi digiti.
The superficial branch separates into two digital nerves: one, the smaller of
the two, supplies the outer side of the little toe, the Flexor brevis minimi digiti,
and the two interosseous muscles of the fourth metatarsal space; the other, and
larger digital branch, supplies the adjoining sides of the fourth and fifth toes, and
communicates with the internal plantar nerve.
The deep or muscular branch accompanies the external plantar artery into the
deep part of the sole of the foot, beneath the tendons of the Flexor muscles and
Adductor pollicis, and supplies all the Interossei (except those in the fourth
metatarsal space), the two outer Lumbricales, the Adductor pollicis, and the
Transversus pedis.
The External Popliteal or Peroneal Nerve, about one-half the size of the
internal popliteal, descends obliquely along the outer side of the popliteal space,
close to the margin of the Biceps muscle, to the fibula; and, about an inch below
the head of this bone, pierces the origin of the Peroneus longus, and divides be-
neath this muscle into the anterior tibial and musculo-cutaneous nei'ves.
The branches of the peroneal nerve, previous to its division, are articular and
cutaneous.
The articular branches, two in number, accompany the superior and inferior
external articular arteries to the outer side of the knee. The upper one occasion-
ally arises from the great sciatic nerve before its "bifurcation. A third (recurrent)
articular nerve is given off at the point of division of the peroneal nerve; it
ascends with the tibial recurrent artery through the Tibialis anticus muscle to
the front of the knee, which it supplies.
The cutaneous branches, two or three in number, supply the integument along
the back part and outer side of the leg, as far as its middle or lower part; one of
these, larger than the rest, the communicans peronei, arises near the head of the
fibula, crosses the external head of the Gastrocnemius to the middle of the leg,
where it joins with the external saphenous. This nerve occasionally exists as a
separate branch, which is continued down as far as the heel.
The Anterior Tibial Nerve commences at the bifurcation of the peroneal «ierve,
between the fibula and upper part of the Peroneus longus, passes obliquely for-
wards beneath the Extensor longus digitorum to the fore part of the interosseous
membrane, and reaches the outer side of the anterior tibial artery above the
middle of the leg; it then descends with the artery to the front of the ankle-joint,
where it divides into an external and an internal branch. This nerve lies at first
on the outer side of the anterior tibial, then in front of it, and again at its outer
.side at the ankle-joint.
The branches of the anterior tibial, in its course through the leg, are muscular:
these supply the Tibialis anticus, the Extensor longus digitorum, and Extensor
proprius pollicis muscles.
The external, or tarsal branch of the anterior tibial, passes outwards across
the tarsus, beneath the Extensor brevis digitorum, and, having become ganglionic,
like the posterior interosseous nerve at the wrist, supplies the Extensor brevis
digitorum and the articulations of the tarsus and metatarsus.
The internal branch, the continuation of the nerve, accompanies the dorsalis
pedis artery along the inner side of the dorsum of the foot, and, at the first inte-
rosseous space, divides into two branches, which supply the adjacent sides of the
great and second toes, communicating with the internal division of the musculo-
cutaneous nerve.
The Musculo- Cutaneous branch supplies the muscles on the fibular side of the
CUTANEOUS NERVES OF FOOT.
53'
leg, and the integument of the dorsum of the foot. It passes forwards between
the Peronei muscles and the Extensor longus digitorum, pierces the deep fascia
at the lower third of the leg, on its front and outer side, and divides into two
branches. This nerve, in its course between the muscles, gives off muscular
branches to the Peroneus longus and brevis, and cutaneous filaments to the
integument of the lower part of the leg.
The internal branch of the musculo-cutaneous nerve, passes in front of the
ankle-joint, and along the dorsum of the foot, it supplies the inner side of the
great toe, and the adjoining sides of the second and third toes. It also supplies
the integument of the inner ankle and inner side of the foot, communicating with
the internal saphenous nerve, and joins with the anterior tibial nerve, between
the great and second toes.
The external branch, the larger, passes along the outer side of the dorsum of
the foot, to be distributed to the adjoining sides of the third, fourth, and fifth
toes. It also supplies the integument of the outer ankle and outer side of the
foot, communicating with the short saphenous nerve. The distribution of these
nerves will be found to vary; together, they supply all the toes excepting the
outer side of the little toe, and the adjoining sides of the great and second toes.
M JT 2
The Sympathetic Nerve.
THE Sympathetic Nerve consists of a series of ganglia connected together by
intervening cords, extending on each side of the vertebral column from the
base of the skull to the coccyx. It may, moreover, be traced up into the head,
where the ganglia occupy spaces between the cranial and facial bones. These
two gangliated cords lie parallel with one another as far as the sacrum, on
which bone they converge, communicating together in front of the coccyx,
through a single ganglion {ganglion impar), placed in front of this bone.
Some anatomists also state that the two cords are joined at their cephalic extre-
mity, through a small ganglion (the ganglion of Ribes), situated upon the anterior
communicating artery. Moreover, the chains of opposite sides communicate
together between these two extremities in several parts, by means of the nervous
cords that arise from them.
The ganglia are somewhat less numerous than the vertebrae: thus there are
only three in the cervical region, twelve in the dorsal, four in the lumbar, five in
the sacral, and one in the coccygeal.
The sympathetic nerve, for convenience of description, may be divided into
several parts, according to the position occupied by each ; and the number of
ganglia of which each part is composed, may be thus arranged:
Cephalic portion
4 ganglia
Cervical „
3 ..
Dorsal „
12 „
Lumbar „
4 "
Sacral „
5 "
Coccygeal „
I ,,
Each ganglion may be regarded as a distinct centre, from, or to, which,
branches pass in various directions. These branches may be thus arranged:
I, Branches of communication between the ganglia. 2. Branches of communi-
cation with the cerebral or spinal nerves. 3. Primary branches passing to be
distributed to the arteries in the vicinity of the ganglia, and to the viscera, or
proceeding to other ganglia placed in the thorax, abdomen, or pelvis.
1. The branches of communication between the ganglia are composed of grey
and white nerve-fibres, the latter being continuous with those fibres of the spinal
nerves which pass to the ganglia.
2. The branches of communication between the ganglia and the cerebral or
spinal nerves, also consist of a white and a grey portion; the former proceeding
from the spinal nerve to the ganglion, the latter passing from the ganglion to the
spinal nerve.
3. The primary branches of distribution also consist of two kinds of nerve-
fibres, the sympathetic and spinal. They have a remarkable tendency to form
intricate plexuses, which encircle the blood-vessels, and are conducted by them
to the viscera. The greater number, however, of these branches pass to a series
of ganglia, or ganglionic masses, of variable size, situated in the large cavities
of the trunk, the thorax, and abdomen; and are connected with the roots of
the great arteries of the viscera. These ganglia are single and unsymmetrical,
and are called the cardiac and semilunar. From these visceral ganglia numerous
plexuses are derived, which entwine round the blood-vessels, and are conducted
by them to the viscera.
SYMPATHETIC NERVE.
273-— The Sympathetic Nerve.
533
Carotid Flexiis
Sitjrerior CervicaZ Ganqlt
Middle Cervical Gaitfflion
Inferior Cervical Ganglion
harytigeuli jBranohes
Cardiac £p4
cep Ca,rdiae Ple^cus
iperfieial Cardiac J'texus
Sol/tf Ples.us
A.orftc J^lexus
Hypo gastric Flex its
Sacral Ganglii
Ga,7i^lion- Trnpa-r.
534
SYMPATHETIC NERVE.
The Cephalic portion of the sympathetic, consists of four ganglia. I. The
ophthalmic ganglion. 2. The spheno-palatine, or Meckel's ganglion. 3. The
otic, or Arnold's ganglion. 4. The submaxillary ganglion.
These have been already described in connection with each of the three
divisions of the fifth nerve.
Cervical Portion of the Sympathetic.
The cervical portion of the sympathetic consists of three ganglia on each side,
which are distinguished according to their position, as the superior, middle, and
inferior cervical.
The Superior Cervical Ganglion, the largest of the three, is placed opposite
the second and third cervical vertebrae, and sometimes as low as the fourth or fifth.
It is of a reddish-grey colour, and usually fusiform in shape: sometimes broad, and
occasionally constricted at intervals, so as to give rise to the opinion, that it con-
sists of the coalescence of several smaller ganglia. It is in relation in front with
the sheath of the internal carotid artery, and internal jugular vein; and behind,
it lies on the Rectus capitis anticus major muscle.
Its branches may be divided into superior, inferior, external, internal, and
anterior.
The superior branch appears to be a direct continuation of the ganglion. It is
soft in texture, and of a reddish colour. It ascends by the side of the internal
carotid artery, and, entering the carotid canal in the temporal bone, divides into
two branches, which lie, one on the outer, and the other on the inner side, of that
vessel.
The outer branch, the larger of the two, distributes filaments to the internal
carotid artery, and forms the carotid plexus.
The inner branch also distributes filaments to the internal carotid, and, con-
tinuing onwards, forms the cavernous plexus.
Carotid Plexus.
The carotid plexus is sitviated on the outer side of the internal carotid.
Filaments from this plexus occasionally form a small gangliform swelling on the
under surface of the artery, which is called the carotid ganglion. The carotid
plexus communicates with the Gasserian ganglion of the fifth, with the sixth
nerve, and spheno-palatine ganglion, and distributes filaments to the wall of the
carotid artery, and to the dura mater (Valentin).
The communicating branches with the sixth nerve consist of one or two fila-
ments, which join that nerve as it lies upon the outer side of the internal carotid.
Other filaments are also connected with the Gasserian ganglion of the fifth nerve.
The communication with the spheno-palatine ganglion is effected by the carotid
portion of the Vidian nerve, which passes forwards, through the cartilaginous
substance filling in the foramen lacerum medium, along the pterygoid canal, to the
spheno-palatine ganglion. In this canal it joins the petrosal branch of the Vidian.
Cavernous Plexus.
The cavernous plexus is situated below, and to the inner side of that part of the
internal carotid, which is placed by the side of the sella Turcica, in the cavernous
sinus, and is formed chiefly by the internal division of the ascending branch from
the superior cervical ganglion. It communicates with the third, fovirth, fifth, and
sixth nerves, and with the ophthalmic ganglion, and distributes filaments to the
wall of the internal carotid. The branch of communication with the third nerve
joins it at its point of division; the branch to the fourth nerve joins it as it lies
on the outer wall of the cavernous sinus; other filaments are connected with the
under surface of the trunk of the ophthalmic nerve; and a second filament of
communication joins the sixth nerve.
The filament of connection with the ophthalmic ganglion arises from the ante-
CERVICAL GANGLIA. 535
rior part of the cavernous plexus; it accompanies the nasal nerve, or continues
forwards as a separate branch.
The terminal filaments from the carotid and cavernous plexuses are prolonged
along the internal carotid, forming plexuses which entwine around the cerebral
and ophthalmic arteries; along the former vessel they may be traced on to the
pia mater; along the latter, into the orbit, where they accompany each of the
subdivisions of the vessel, a separate plexus passing with the arteria centralis
retinee into the interior of the eyeball.
The inferior, or descending branch of the superior cervical ganglion commu-
nicates with the middle cervical ganglion.
The external branches are numerous, and communicate with the cranial nerves,
and with the first four cervical nerves. The branches of communication with the
cranial nerves consist of delicate filaments, which pass from the superior cervical
ganglion to the ganglion of the trunk of the pneumogastric, and to the ninth
nerve. A separate filament from the cervical ganglion subdivides and joins the
petrosal ganglion of the glosso-pharyngeal, and the ganglion of the root of the
pneumogastric in the jugular foramen.
The internal branches are three in number; pharyngeal, laryngeal, and the
superior cardiac nerve. The pharyngeal branches pass obliquely inwards to the
side of the pharynx, where they communicate with branches from the pneumo-
gastric, glosso-pharyngeal, and external laryngeal nerves, and assist in forming
the pharyngeal plexus. The laryngeal branches unite with the superior laryn-
geal nerve and its branches.
The superior cardiac nerve will be described in connection with the other
cardiac nerves.
The anterior branches ramify upon the external carotid artery and its branches,
forming around each a delicate plexus, on the nerves composing which small
ganglia are occasionally found. These ganglia have been named, according to
their position, intercarotid (one placed at the angle of bifurcation of the common
carotid), lingual, temporal, and pharyngeal. The plexuses accompanying some of
these arteries have important communications with other nerves. That surround-
ing the external carotid, is connected with the digastric branch of the facial; that
surrounding the facial, communicates with the submaxillary ganglion by one or
two filaments; and that accompanying the middle meningeal artery, sends offsets
which pass to the otic ganglion and to the intumescentia ganglioformis of the facial
nerve.
The Middle Cervical Ganglion (thyroid ganglion) is the smallest of the
three cervical ganglia, and is occasionally altogether wanting. It is placed oppo-
site the fifth cervical vertebra, usually upon the inferior thyroid artery; hence
the name ' thyroid ganglion,' assigned to it by Haller.
Its superior branches ascend to communicate with the superior cervical gan-
glion.
Its inferior branches descend to communicate with the inferior cervical gan-
glion.
Its external branches pass outwards to join the fifth and sixth cervical nerves.
These branches are not constantly found.
Its internal branches are the thyroid, and the middle cardiac nerve.
The thyroid branches are small filaments, which accompany the inferior thyroid
artery to the thyroid gland; they communicate, on the artery, with the superior
cardiac nerve, and in the gland with branches from the recurrent and external
laryngeal nerves.
The middle cardiac nerve is described with the other cardiac nerves.
The Inferior Cervical Ganglion is situated between the base of the trans-
verse process of the last cervical vertebra and the neck of the first rib, on the
inner side of the superior intercostal artery. Its form is irregular; it is larger in
size than the preceding, and frequently joined with the first thoracic ganglion.
Its superior branches communicate with the middle cervical ganglion.
536 SYMPATHETIC NERVE.
Its inferior branches descend, some in front, others behind the subclavian
artery, to join the first thoracic ganglion. The most important of these branches
constitutes the inferior cardiac nerve, to be presently described.
The external branches consist of several filaments, some of which communicate
with the seventh and eighth cervical nerves; others accompany the vertebral
artery along the vertebral canal, forming a plexus around this vessel, supplying
it with filaments, and communicating with the cervical spinal nerves as high as
the fourth.
CardIxVC Nerves.
The cardiac nerves are three in number; superior, middle, and inferior, one
being derived from each of the cervical ganglia.
The Superior Cardiac Nerve (nervus superficialis cordis) arises by two oi
more branches from the superior cervical ganglion, and occasionally receives a
filament from the cord of communication between the first and second cervical
ganglia. It runs down the neck behind the common carotid artery, lying upon the
Longus colli muscle; and crosses in front of the inferior thyroid artery, and the
recurrent laryngeal nerve.
The right superior cardiac nerve, at the root of the neck, passes either in
front or behind the subclavian artery, and along the arteria innominata, to the
back part of the arch of the aorta, to the deep cardiac plexus. This nerve, in its
course, is connected with other branches of the sympathetic; about the middle of
the neck it receives filaments from the external laryngeal nerve; lower down, one
or two twigs from the pneumogastric; and as it enters the thorax, it joins with
the recurrent laryngeal. Filaments from this nerve accompany the inferior thy-
roid artery to the thyroid gland.
The left superior cardiac nerve runs by the 'side of the left carotid artery,
and in front of the arch of the aorta, to the superficial cardiac plexus; it occa-
sionally passes behind this vessel, and terminates in the deep cardiac plexus.
The Middle Cardiac Nerve (nervus cardiacus magnus), the largest of the
three, arises from the middle cervical ganglion, or from the interganglionic cord
between the middle and inferior ganglia. On the right side, it descends behind
the common carotid artery; and at the root of the neck passes either in front or
behind the subclavian artery; it then descends on the trachea, receives a few
filaments from the recurrent laryngeal nerve, and joins the deep cardiac plexus.
In the neck, it communicates with the superior cardiac and recurrent laryngeal
nerves. On the left side, the middle cardiac nerve enters the chest between the
left carotid and subclavian arteries, and joins the left side of the deep cardiac
plexus.
The Inferior Cardiac Nerve (nervus cardiacus minor) arises from the inferior
cervical or first thoracic ganglion. It passes down behind the subclavian artery,
and along the front of the trachea, to join the deep cardiac plexus. It communi-
cates freely behind the subclavian artery with the recurrent laryngeal and middle
cardiac nerves.
The Great or Deep Cardiac Plexus {Plexus Magnus Profundus — Scarpa) is
situated in front of the trachea at its bifurcation, above the point of division of
the pulmonary artery, and behind the arch of the aorta. It is formed by the
cardiac nerves derived from the cervical ganglia of the sympathetic, and the
cardiac branches of the recurrent laryngeal and pneumogastric. The only cardiac
nerves which do not enter into the formation of this plexus are the left superior
cardiac nerve and the left inferior cardiac branch from the pneumogastric. The
branches derived from the great cardiac plexus form the posterior coronary
plexus and part of the anterior coronary plexus, whilst a few filaments proceed to
the pulmonary plexuses, and to the auricles of the heart.
The branches from t\\e right side of this plexus pass some in front and others
behind the right pulmonary artery; the former, the more numerous, transmit a
few filaments to the anterior pulmonary plexus, and are continued along the trunk
THORACIC GANGLIA. 537
of the pulmonary artery, to form part of the anterior coronary plexus; those be-
hind the pulmonary artery distribute a few filaments to the right auricle, and form
part of the posterior coronary plexus.
The branches from the left side of the cardiac plexus distribute a few filaments
to the left auricle of the heart and the anterior pulmonary plexus, and then pass
on to form the greater part of the posterior coronary plexus, a few branches
passing to the superficial cardiac plexus.
The Superficial or Anterior Cardiac Plexus lies beneath the arch of the aorta,
in front of the right pulmonary artery. It is formed by the left superior cardiac
nerve, the left (and occasionally the right) inferior cardiac branches of the pneu-
mogastric, and by filaments from the deep cardiac plexus. A small ganglion
(cardiac ganglion of Wrisberg) is occasionally found connected with these nerves
at their point of junction. This ganglion, when present, is situated immediately
beneath the arch of the aorta, on the right side of the ductus arteriosus. The
superficial cardiac plexus forms the anterior part of the great coronary plexus,
and several filaments pass along the pulmonary artery to the left anterior pul-
monary plexus.
The Posterior Coronary Plexus is formed chiefly by filaments from the left side
of the deep cardiac plexus, and by a few from the right side. It suiTounds the
branches of the coronary artery at the back of the heart, and its filaments are
distributed with those vessels to the muscular substance of the ventricles.
The Anterior Coronary Plexus is prolonged chiefly from the superficial cardiac
plexus, but receives filaments from the deep cardiac plexus. Passing forwards
between the aorta and pulmonary artery, it accompanies the right coronary artery
on the anterior surface of the heart.
Valentin has described nervous filaments ramifying under the endocardium;
but they are less distinct in man than in mammalia ; and Remak and Lee have
found, in several mammalia (the latter in man), numerous small ganglia on the
branches of these nerves, both on the surface of the heart and in its muscular
substance.
Thoracic Part of the Sympathetic.
The thoracic portion of the sympathetic consists of a series of ganglia, which
usually correspond in number to that of the vertebrse; but, from the occasional
coalescence of two, their number is uncertain. These ganglia are placed on
each side of the spine, resting against the heads of the ribs, and covered by the
pleura costalis: the last two are, however, anterior to the rest, being placed on
the side of the bodies of the vertebrae. The ganglia are small in size, and of
a greyish colour. The first, larger than the rest, is of an elongated form, and
usually blended with the last cervical. They are connected together by cord-like
prolongations from their substance.
The external branches from each ganglion, usually two in number, communicate
with each of the dorsal spinal nerves.
The internal branches from the six upper ganglia Vive very small, and distribute
filaments to the thoracic aorta and its branches, besides small branches to the
bodies of the vertebrae and their ligaments.
Branches from the third and fourth ganglia form part of the posterior pul-
monary plexus.
The branches of the six lower ganglia are large and white in colour; they
distribute filaments to the aorta, and unite to form the three splanchnic nerves.
These are named, the great, the lesser, and the smallest or renal splanchnic.
The Great Splanchnic Nerve is of a white colour, firm in texture, and bears a
marked contrast to the ganglionic nerves. It is formed by branches from all
the thoracic ganglia from the sixth to the tenth, receiving filaments (according to
Mr. Beck) from all the thoracic ganglia above the sixth. These roots unite to
form a large round cord of considerable size. It descends obliquely inwards in
front of the bodies of the vertebrae along the posterior mediastinum, perforates the
538 SYMPATHETIC NERVE.
crus of the Diaphragm, and terminates in the semilunar ganglion, distributing
filaments to the renal plexus and supra-renal gland.
The Lesser Splanchnic Nerve is formed by filaments from the tenth and
eleventh ganglia, and from the cord between them. It pierces the Diaphragm
with the preceding nerve, and joins the coeliac plexus. It communicates in the
chest with the great splanchnic nerve, and occasionally sends filaments to the
renal plexus.
The Smallest or Renal Splanchnic Nerve arises from the last ganglion, and
piercing the Diaphragm, terminates in the renal plexus and lower part of the coeliac
plexus. It occasionally communicates with the preceding nerve.
A striking analogy appears to exist between the splanchnic and the cardiac
nerves. The cardiac nerves are three in number; they arise from the three
cervical ganglia, and are distributed to a large and important organ in the thoracic
cavity. The splanchnic nerves, also three in numb'er, are connected with all the
dorsal ganglia, and are distributed to important organs in the abdominal cavity.
The Epigastric or Solar Plexus supplies all the viscera in the abdominal
cavity. It consists of a dense network of nerves and ganglia, situated behind the
stomach and in front of the aorta and crura of the Diaphragm. It surrounds the
coeliac axis and root of the superior mesenteric artery, extending downwards as
low as the pancreas, and outwards to the supra-renal capsules. This plexus, and
the ganglia connected with it, receive the great splanchnic nerve of both sides,
part of the lesser splanchnic nerves, and the termination of the right pneurao-
gastric. It distributes filaments, which accompany, under the name of plexuses,
all the branches from the front of the abdominal aorta.
The semilunar ganglia, two in number, one on each side, are the largest gan-
glia in the body. They are large irregular gangliform masses, formed by the
aggregation of smaller ganglia, having interspaces between them. They are
situated by the side of the coeliac axis and superior mesenteric artery, close to
the supra-renal glands: the one on the right side lies beneath the vena cava;
the upper part of each ganglion is joined by the greater and lesser splanchnic
nerves, and to the inner side of each the branches of the solar plexus are con-
nected.
From the solar plexus are derived the following:
Phrenic or Diaphragmatic plexus. Renal plexus.
Gastric plexus. Superior mesenteric plexus.
Hepatic plexus. Spermatic plexus.
Splenic plexus. Inferior mesenteric plexus.
Supra-renal plexus.
The Phrenic Plexus accompanies the phrenic artery to the Diaphragm, which
it supplies, some filaments passing to the supra-renal gland. It arises from the
upper part of the semilunar ganglion, and is larger on the right than on the left
side. In connexion with this plexus, on the right side, at its point of junction
with the phrenic nerve, is a small ganglion (ganglion diaphragmaticum). This
ganglion is placed on the under surface of the Diaphragm, near the supra-renal
gland. Its branches are distributed to the vena cava, supra-renal gland, and the
hepatic plexus. The ganglion is absent on the left side.
The Supra-Renal Plexus is formed by branches from the solar plexus, from
the semilunar ganglion, and from the splanchnic and phrenic nerves, a ganglion
being formed at the point of junction of the latter nerve. It supplies the
supra-renal gland. The branches of this plexus are remarkable for their large
size, in comparison with the size of the organ they supply.
The Renal Plexus is formed by filaments from the solar plexus, the outer part
of the semilunar ganglion, and the aortic plexus. It is also joined by filaments
from the lesser and smallest splanchnic nerves. The nerves from these sources,
fifteen or twenty in number, have numerous ganglia developed upon them. They
accompany the branches of the renal artery into the kidney; some filaments on
SOLAR PLEXUS; SEMILUNAR GANGLIA. 539
the right side being distributed to the vena cava, and others to the spermatic
plexus, on both sides.
The Spermatic Plexus is derived from the renal plexus, receiving branches
from the aortic plexus. It accompanies the spermatic vessels to the testes.
In the female, the ovarian plexus is distributed to the ovaries and fundus of
the uterus.
The Cceliac Plexus, of large size, is a direct continuation from the solar
plexus: it surrounds the cseliac artery, and subdivides into the gastric, hepatic,
and splenic plexuses. It receives branches from one or more of the splanchnic
nerves, and, on the left side, a filament from the pneumogastric.
The Gastric Plexus accompanies the gastric artery along the lesser curvature
of the stomach, and joins with branches from the left pneumogastric nerve. It is
distributed to the stomach.
The Hepatic Plexus, the largest offset from the casliac plexus, receives filaments
from the left pneumogastric and right phrenic nerves. It accompanies the
hepatic artery, ramifying in the substance of the liver, upon its branches, and
upon those of the vena portse.
Branches from this plexus accompany all the divisions of the hepatic artery.
Thus there is a pyloric plexus accompanying the pyloric branch of the hepatic,
which joins with the gastric plexus, and pneumogastric nerves. There is also
a gastro-duodenal plexus, which subdivides into the pancreatico-duodenal plexus,
which accompanies the pancreatico-duodenal artery, to supply the pancreas and
duodenum, joining with branches from the mesenteric plexus; and a gastro-
epiploic plexus, which accompanies the right gastro-epiploic artery along the
greater curvature of the stomach, and anastomoses with branches from the splenic
plexus. A cystic plexus, which supplies the gall-bladder, also arises from the
hepatic plexus, near the liver.
The Splenic Plexus is formed by branches from the right and left semilunar
ganglia, and from the right pneumogastric nerve. It accompanies the splenic
artery and its branches to the substance of the spleen, giving off, in its course,
filaments to the pancreas (pancreatic plexus), and the left gastro-epiploic plexus,
which accompanies the gastro-epiploica sinistra artery along the convex border of
the stomach.
The Superior Mesenteric Plexus is a continuation of the lower part of the great
solar plexus, receiving a branch from the junction of the right pneumogastric
nerve with the cseliac plexus. It surrounds the superior mesenteric artery, which
it accompanies into the mesentery, and divides into a number of secondary
plexuses, which are distributed to all the parts supplied by the artery, viz.,
pancreatic branches to the pancreas; intestinal branches, which supply the whole
of the small intestine; and ileo-colic, right colic, and middle colic branches, which
supply the corresponding parts of the great intestine. The nerves composing
this plexus are white in colour, and firm in texture, and have numerous ganglia
developed upon them near their origin.
The Aortic Plexus is formed by branches on each side, from the semilunar
ganglia and renal plexuses, receiving filaments from some of the lumbar ganglia.
It is situated upon the sides and front of the aorta, between the origins of the
superior and inferior mesenteric arteries. From this plexus arises the inferior
mesenteric, part of the spermatic, and the hypogastric plexuses; and it distributes
filaments to the inferior cava.
The Inferior Mesenteric Plexus is derived chiefly from the left side of the
aortic plexus. It surrounds the inferior mesenteric artery, and divides into a
number of secondary plexuses, which are distributed to all the parts supplied by
the artery, viz., the left colic and sigmoid plexuses, to the descending and sigmoid
flexure of the colon; and the superior hsemorrhoidal plexus, which supplies the
upper part of the rectum, and joins in the pelvis with branches of the left
hypogastric plexus.
540
SYMPATHETIC NERVE.
The Lumbar Portion of the Sympathetic.
The lumbar portion of the sympathetic is situated in front of the vertebral
column, along the inner margin of the Psoas muscle. It consists usually of four
ganglia, connected together by interganglionic cords. The ganglia are of small
size, of a greyish colour, hordeiform in shape, and placed much nearer the median
line than the thoracic ganglia.
The superior and inferior branches of the lumbar ganglia, serve to communicate
between the chain of ganglia in this region. They are usually single, and of a
white colour.
The external branches communicate with the lumbar spinal nerves. From the
situation of the lumbar ganglia, these branches are longer than in the other
regions. They are usually two in number for each ganglion, and accompany the
lumbar arteries around the sides of the bodies of the vertebrae, passing beneath
the fibrous arches from which the fibres of the Psoas muscle partly arise.
The internal branches pass inwards, in front of the aorta, and form the lumbar
aortic plexus (already described). Other branches descend in front of the com-
mon iliac arteries, and join, over the promontory of the sacrum, to form the
hypogastric plexus. Numerous delicate filaments are also distributed to the
bodies of the vertebrae, and the ligaments connecting them.
Pelvic Portion of the Sympathetic.
The pelvic portion of the sympathetic is situated in front of the sacrum, along
the inner side of the anterior sacral foramina. It consists of four or five small
ganglia on each side, connected together by inter-ganglionic cords. Below, they
converge and unite on the front of the coccyx, by means of a small ganglion
(ganglion impar).
The superior and inferior branches, are the cords of communication between
the ganglia above and below.
The external branches, exceedingly short, communicate with the sacral nerves.
They are two in number to each ganglion. The coccygeal nerve communicates
either with the last sacral, or coccygeal ganglion.
The internal branches communicate, on the front of the sacrum, with the
corresponding branches from the opposite side; some, from the first two ganglia,
pass to join the pelvic plexus, and others form a plexus, which accompanies the
middle sacral artery.
The Hypogastric Plexus supplies the viscera of the pelvic cavity. It is
situated in front of the promontory of the sacrum, between the two common iliac
arteries, and is formed by the union of numerous filaments, which descend on
each side from the aortic plexus, from the lumbar ganglia, and from the first two
sacral ganglia. This plexus contains no ganglia, and bifurcates, below, into two
lateral portions, which form the inferior hypogastric, or pelvic plexuses.
Inferior Hypogastric, or Pelvic Plexus,
The inferior hypogastric, or pelvic plexus, is situated at the side of the rec-
tum and bladder in the male, and at the side of the rectum, vagina, and bladder,
in the female. It is formed by a continuation of the hypogastric plexus, by
branches from the second, third, and fourth sacral nerves, and by a few filaments
from the sacral ganglia. At the point of junction of these nerves, small ganglia
are found. From this plexus numerous branches are distributed to all the
viscera of the pelvis. They accompany the branches of the internal iliac
artery.
The Inferior Hcemorrhoidal Plexus arises from the back part of the pelvic
plexus. It supplies the rectum, joining with branches of the superior hasmorrhoidal
plexus.
The Vesical Plexus arises from the fore part of the pelvic plexus. The nerves
composing it are numerous, and contain a large proportion of spinal nerve-fibres.
PELVIC PLEXUS.
541
They accompany the vesical arteries, and are distributed to the side and base of
the bladder. Numerous filaments also pass to the vesicular seminales, and vas
deferens: those accompanying the vas deferens join, on the spermatic cord, with
branches from the spermatic plexus.
The Prostatic Plexus is continued from the lower part of the pelvic plexus.
The nerves composing it are of large size. They are distributed to the pro-
state gland, vesicula3 seminales, and erectile structure of the penis. The nerves
supplying the erectile structure of the penis, consist of two sets, the small and
large cavernous nerves. They are slender filaments, which arise from the fore
part of the prostatic plexus, and after joining with branches from the internal
pudic nerve, pass forwards beneath the pubic arch.
The small cavernous nerves perforate the fibrous covering of the penis, near
its root.
The large cavernous nerve passes forwards along the dorsum of the penis, joins
with the dorsal branch of the pudic nerve, and is distributed to the corpus caver-
nosum and spongiosum.
The Vaginal Plexus arises from the lower part of the pelvic plexus. It is lost
on the walls of the vagina, being distributed to the erectile tissue at its anterior
part, and to the mucous membrane. The nerves composing this plexus, contain,
like the vesical, a large proportion of spinal nerve-fibres.
The Uterine Nerves arise from the lower part of the hypogastric plexus, above
the point where the branches from the sacral nerves join the pelvic plexus. They
accompany the uterine arteries to the side of the organ between the layers of the
broad ligament, and are distributed to the cervix and lower part of the body of
the uterus, penetrating its substance.
Other filaments pass separately to the body of the uterus and Fallopian tube.
Branches from the hypogastric plexus accompany the uterine arteries into the
substance of the uterus. Upon these filaments ganglionic enlargements are found.
Organs of Sense.
THE Organs of the Senses are the instruments by which the mind is brought
into relation with external objects. These organs are five in number, viz.
the organs of touch, of smell, of taste, of hearing, and of sight.
The Skin.
The skin is the principal seat of the sense of touch, and may be regarded as a
covering of protection to the exterior of the body. It consists of two layers, the
derma or cutis vera, and the epidermis or cuticle.
The Derma, or True Skin, consists of fibro-areolar tissue, intermixed with
numerous blood-vessels, lymphatics, and nerves. The fibro-areolar tissue forms
the framework of the cutis; it is composed of firm interlacing bundles of white
fibrous tissue, intermixed with a much smaller proportion of yellow elastic fibres,
the amount of which varies in different parts. The fibro-areolar tissue is more
abundant in the deeper layers of the cutis, where it is dense and firm, the meshes
274. — A Sectional View of the Skin (magnified).
being large, and gradually becoming blended with the subcutaneous areolar tissue;
towards the surface, the fibres become finer and more closely interlaced, the most
THE SKIN.
543
superficial layer being covered with numerous small, conical, vascular eminences,
the papillae. From these differences in the structure of the cutis at different
parts, it is usual to describe it as consisting of two layers; the deeper layer or
corium, and the superficial or papillary layer.
The Corium consists of strong interlacing fibrous bands, composed chiefly of
the Avhite variety of fibrous tissue; but containing, also, some fibres of the yellow
elastic tissue, which vary in amount in diflerent parts. Towards the attached
surface, the fasciculi are large and coarse; and the areolae left by their interlacino-
large and occupied by adipose tissue and the svxdatory glands. This element of
the skin becomes gradually blended with the subcutaneous areolar tissue. To-
wards the free surface, the fasciculi are much finer, and they have a closer
interlacing, the most superficial layers consisting of a transparent, homogeneous
matrix with imbedded nuclei.
The corium varies in thickness, from a quarter of a line to a line and a half, in
different parts of the body. Thus, it is thicker in the more exposed regions, as
the palm of the hand and sole of the foot; on the posterior aspect of the body,
than the front; and on the outer, than the inner side of the limbs. In the eye-
lids, scrotum, and penis, it is exceedingly thin and delicate. The skin generally
is thicker in the male than in the female.
The areolce are occupied by adipose tissue, hair follicles, and the sudatory and
sebaceous glands ; they are the channel by which the vessels and nerves are
distributed to the more superficial strata of the corium, and to the papillaiy
layer.
Plain muscular fibres are found in the superficial layers of the corium, wherever
hairs are found; and in the subcutaneous areolar tissue of the scrotum, penis,
perineum, and areolas of the nipple. In the latter situations, the fibres are
arranged in bands, closely reticulated and disposed in super-imposed lamina3.
The Papillary Layer is situated upon the free surface of the corium; it con-
sists of numerous small, highly sensitive, and vascular eminences, the papillae,
which rise perpendicularly from its surface, and form the essential element of the
organ of touch. The papillfe are conical-shaped eminences, having a round or
blunted extremity, occasionally divided into two or more parts, and connected by
their base with the free surface of the corium. On the general surface of the body,
more especially in those parts which are endowed with slight sensibility, they are
few in number, short, exceedingly minute, and ii-regularly scattered over the sur-
face; but in other situations, as upon the palmar surface of the hands and fingers,
upon the sole, and around the nipple, they are long, of large size, closely aggregated
together, and arranged in curvilinear lines, forming the elevated ridges seen on
the free surface of the epidennis. In these ridges, the larger papillae are arranged
in a double row, with smaller papillae between them; and these rows are sub-
divided into small square-shaped masses by short transverse furrows regularly
disposed, in the centre of each of which is the minute orifice of the duct of a
sweat-gland. No papillge exist in the grooves between the ridges. In structure,
the papillae resemble the superficial layer of the cutis; consisting of a homogeneous
tissue, faintly fibrillated, and containing a few fine elastic fibres. The smaller
papillae contain a single capillary loop ; but in the larger the vessels are convoluted
to a greater or less degree; each papilla also contains two or more nerve-fibres,
which, after running in a waving manner through it, terminate in loops, or by a
free extremity. No lymphatics have as yet been discovered in the papillae.
The Epidermis, or Cuticle (scarf-skin), is an epithelial structure, which forms
a defensive covering to the surface of the true skin, being accurately moulded
on the papillary layer of the derma. It varies in thickness in diffei-ent parts.
Where it is exposed to pressure and the influence of the atmosphere, as upon the
palms of the hands and soles of the feet, it is thick, hard, and horny in texture;
whilst that which lies in contact with the papillary layer, over the entire surface
of the body, is soft and cellular in structure; hence the deeper layer has been
called, the rete mucosum.
544 ORGANS OF SENSE.
The free surface of the epidermis is marked by a network of linear furrows of
variable size, marking out the surface into a number of spaces of polygonal or
lozenge-shaped form. Some of these furrows are large, as opposite the flexures
of the joints, and correspond to the folds in the derma produced by their move-
ments. In other situations, as upon the back of the hand, they are exceedingly
fine, and intersect one another at various angles: upon the palmar surface of the
hand and fingers, and upon the sole, these lines are very distinct, and have a
curvilinear arrangement, and depend upon the large size and peculiar arrangement
of the papillae upon which the epidermis is placed. The deep surface of the
epidermis is accurately moulded upon the papillary layer of the derma, each
papilla being invested by its epidermic sheath; so that when this layer is removed
by maceration, it presents a number of pits or depressions corresponding to the
elevations of the papillae, as well as the furrows left in the interval between them.
Fine tubular prolongations from this layer are continued into the ducts of the
sudatory and sebaceous glands. In structure, the epidermis consists of flattened
cells, agglutinated together, and having a laminated arrangement. In the deeper
layers the cells are large, rounded or columnar, and filled with soft opaque con-
tents. In the superficial layers the cells are flattened, transparent, dry, and firm,
and their contents converted into a kind of horny matter. The difference in
the structure of these layers is dependent upon the mode of growth of the
epidermis. As the external layers desquamate, from their being constantly sub-
jected to attrition, they are reproduced from beneath, successive layers gradually
approaching towards the free surface, which, in their turn, die and are cast off.
These cells arise in the liquor sanguinis, which is poured out on the free sur-
face of the derma; they contain nuclei, and form a thin stratum of closely-aggre-
gated nucleated cells, which cover the entire extent of the papillary layer. The
deepest layer of cells, according to Kolliker, ate of a columnar form, and are
arranged perpendicularly to the free surface of the derma, forming either a single
or a double, or even triple, layer: the laminae succeeding these are composed of
cells of a more rounded form, the contents of which are soft, opaque, granular, and
soluble in acetic acid. As these cells successively approach the surface by the
development of fresh layers from beneath, they assume a flattened form from the
evaporation of their fluid contents, and finally form a transparent, dry, mem-
branous scale, lose their nuclei, and apparently become changed in their chemical
composition, as they are unaffected now by acetic acid.
The black colour of the skin in the negro, and the tawny colour among some of
the white races, is due to the presence of pigment in the cells of the cuticle.
This pigment is more especially distinct in the cells of the deeper layer, or rete
mucosum, and is caused by the presence of pigment cells, similar to those found
in the choroid. As these approach the surface and desiccate, the colour becomes
partially lost.
The arteries which supply the skin divide into numerous branches in the sub-
cutaneous tissue; they then pass through the areolae of the corium, and divide into
a dense capillary plexus, which supplies the sudatory and sebiparous glands and
the hair follicles, terminating in the superficial layers of the corium, by forming a
capillary network, from which numerous fine branches ascend to the papillae.
The lymphatic vessels are arranged in a minute plexiform network in the
superficial layers of the corium, where they beX3ome interwoven with the capillary
and nervous plexuses; they are especially abundant in the scrotum and around
the nipple.
The nerves which supply the skin ascend with the vessels through the areolas
of the deep layers of the corium to the more superficial layers, where they form a
minute plexiform mesh. From this plexus, the primitive nerve-fibres pass to be
distributed to the papilla. The nerves are most numerous in those parts which are
provided with the greatest sensibility.
THE SKIN.
Appendages of the Skin.
545
The appendages of the skin are the nails, the hairs, the sudoriferous and seba-
ceous glands, and their ducts.
The nails and hairs are peculiar modifications of the epidermis, consisting essen-
tially of the same cellular structure as that membrane.
The Nails are flattened elastic structures of a horny texture, placed upon the
dorsal surface of the terminal phalanges of the fingers and toes. Each nail is
convex on its outer surface, concave v/ithin, and is implanted by a portion called
the root into a groove of the skin; the exposed portion is called the body, and the
anterior extremity the free edge. The nail has a very firm adhesion to the cutis,
being accurately moulded upon its surface, as the epidermis is in other parts.
The part of the cutis beneath the body and root of the nail is called the matrix,
from its being the part from which the nail is produced. Corresponding to the
body, the matrix is thick, and covered with large highly vascular papillae, arranged
in longitudinal rows, the colour of which is seen through the transparent tissue.
Behind this, near the root of the nail, the papillte are small, less vascular, and
have no regular arrangement; hence the portion of the nail corresponding to this
part is of a whiter colour, and called lunula, from its form.
The cuticle, as it passes forwards on the dorsal surface of the finger, is attached
to the surface of the nail a little in advance of its root: at the extremity of the
finger, it is connected with the under surface of the nail, a little behind its free
edge. The cuticle and horny structure of the nail (both epidermic structures)
are thus seen to be directly continuous with each other. The nails, in structure,
consist of cells having a laminated arrangement, and these are almost essentially
similar to those composing the epidermis. The deepest layer of cells which lie in
contact with the papillse at the root and under surface of the nail are of elongated
form, arranged perpendicularly to the surface, and provided with nuclei; those
which succeed these are of a rounded or polygonal form, the more superficial
ones becoming broad, thin, and flattened, and so closely compacted together as to
make the limits of each cell very indistinct.
It is by the successive growth of new cells at the root and under surface of the
body of the nail, that it advances forwards, and maintains a due thickness, whilst,
at the same time, the growth of the nail in the proper direction is secured. As
these cells in their turn become displaced by the growth of new cells, they assume
a flattened form, lose their nuclei, and finally become closely compacted together
into a firm dense horny texture. In chemical composition, the nails resemble
the epidermis. According to Mulder, they contain a somewhat larger proportion
of carbon and sulphur.
Hairs are peculiar modifications of the epidermis, and consist essentially of the
same structure as that membrane. They are found on nearly every part of the
surface of the body, excepting the palms of the hands and soles of the feet, and
vary much in length, thickness, and colour in different parts of the body, and in
the different races of mankind. In some parts they are so short as not to pro-
ject beyond the follicle containing them; in other parts, as upon the scalp, they
are of considerable length; along the margin of the eyelids and upon the face
they are remarkable for their thickness. A hair consists of a root, the part im-
planted in the skin; the shaft, the portion projecting from its surface; and the
point. They generally present a cylindrical or more or less flattened form, and a
reniform outline upon a transverse section.
The root of the hair presents a bulbous enlargement at its extremity; it is
whiter in colour, and softer in texture, than the stem, and is lodged in a follicular
involution of the epidermis, called the hair follicle. When the hair is of considerable
length, the follicle extends into the subcutaneous cellular tissue. The hair folli-
cle is bulbous at its deep extremity, like the hair which it contains, and has open-
ing into it, near its free extremity, the orifices of the ducts of one or more sebaceous
glands. In structure, the hair follicle consists of two' coats; an outer or dermic,
N N
546 ORGANS OF SENSE.
and an inner or cuticular. The outer coat is formed mainly of areolar tissue; it
is continuous with the corium, is highly vascular, and supplied by numerous
minute nervous filaments. The inner or cuticular lining is continuous with the
epidermis, and, at the bottom of the hair follicle, with the root of the hair; this
cuticular lining resembles the epidermis in the peculiar rounded form and soft
character of those cells which lie in contact with the outer coat of the hair follicle,
and the thin, dry, and scaly character of those which lie near the surface of the
hair, to which they are closely adherent. When the hair is plucked from its
follicle, this cuticular lining most commonly adheres to it, and forms what is called
the root sheath. At the bottom of each hair follicle is a small conical-shaped
vascular eminence or papilla, similar in every respect to those found upon the
surface of the skin; it is continuous with the dermic layer of the follicle, is highly
vascular, and probably supplied with nervous fibrils: this is the part through
which material is supplied for the production and constant growth of the hair.
The root of the hair rests upon this conical-shaped eminence, and is continuous
with the cuticular lining of the follicle at this part. It consists of nucleated cells,
similar in every respect to those which in other situations form the epidermis.
These cells gradually enlarge as they are pushed upwards into the soft bulb, and
some of them contain pigment granules, which exist either in separate cells, or
the granules are separate but aggregated around the nucleus; it is these granules
which give rise to the colour of the hair. It occasionally happens that these
pigment granules completely fill the cells in the centre of the bulb, which gives
rise to the dark tract of pigment often found, of greater or less length, in the axis
of the hair.
The shaft of the hair consists of a central part, or medulla; surrounding this is
the fibrous part of the hair, covered externally by the cortex. The medulla
occupies the centre of the shaft, and ceases towards the point of the hair. It is
usually wanting in the fine hairs covering the surface of the body, and com-
monly in those of the head. It is more opaque and deeper coloured than the
fibrous part, and consists of cells containing pigment or fat granules. The
fibrous portion of the hair constitutes the chief part of the stem ; its cells are
elongated, and unite to form flattened fusiform fibres. These also contain pig-
ment granules, which assume a linear arrangement. The cells which form the
cortex of the hair consist of a single layer, which surrounds those about to form
the fibrous layer; they are converted into thin flat scales, having an imbricated
arrangement.
The Sebaceous Glands are small sacculated glandular organs, lodged in the sub-
stance of the corium, or sub-dermoid tissue. They are found in all parts of the skin,
but are most abundant in the face, and in those parts which are exposed to friction.
Their orifices open most frequently into the hair follicles, but occasionally upon
the general surface. Each gland consists of a single duct, which is more or less
capacious, and terminates in a lobulated pouch-like extremity. The basement
membrane forming the wall of the sac, as well as the duct, is lined by epithelium,
which is filled with particles of sebaceous matter; and this becoming detached
into the cavity of the sac, as its growth is renewed, constitutes the secretion. The
number of sacculi connected with the duct vary from two to five, or even twenty,
in number. On the nose and face the glands are of large size, distinctly lobulated,
and often become much enlarged from the accumulation of pent-up secretion.
The largest sebaceous glands are those found in the eyelids, the Meibomian
glands.
The Sudoriferous or Siveat- Glands are found in almost every part of the skin,
and are situated in small pits in the deep parts of the corium, or in the subcuta-
neous areolar tissue, surrounded by a quantity of adipose tissue. They are small,
round, reddish bodies, consisting of one or more convoluted tubuli, from which
the efferent duct proceeds upwards through the corium and cuticle, and opens
upon the surface by a slightly enlarged orifice. The efferent duct, as it passes
tlirough the corium, pursues a curved and slightly serpentine course, and if the
THE TONGUE. 547
epidermis is thin, opens directly upon tlie surface; but where the epidermis if?
thicker, it assumes a spiral arrangement, the separate windings of the tube being
as close and as regular as those of a common screw. The spiral coui'se of these
ducts is esiiecially distinct in the thick cuticle of the palm of the hand and sole of
the foot. The size of these glands varies. They are especially large in those
regions where the amount of perspiration is great, as in the axillae, where they
form a thin mammillated layer of a reddish colour, which corresponds exactly to
the situation of the hair in this region; they are large, also, in the groin. Their
number varies. They are most numerous on the palm of the hand, and pre-
sent, according to Krause, 2,800 orifices on a square inch of the integument, and
a rather less number on the sole of the foot. In both of these situations, the
orifices of the ducts are exceedingly regular, and correspond to the small trans-
verse grooves which intersect the ridges of papillaj. In other situations they are
more irregularly scattered; but in nearly equal numbers over parts including the
same extent of surface. Each gland consists of a single tube intricately convo-
luted, at one end terminating by a blind extremity; at the other end opening
upon the surface of the skin. In the larger glands, this single duct usually
divides and subdivides dichotomously; and these smaller ducts ultimately ter-
minate in short caecal pouches, rarely anastomosing. The wall of the duct is
thick; the width of the canal rarely exceeding one-third of its diameter. The
tube, both in the gland and where it forms the excretory duct, consists of two
layers: an outer, formed by fine areolar tissue; and an epithelium lining its inte-
rior. The external, or fibro-cellular coat, is thin, continuous with the superficial
layer of the corium, and extends only as high as the surface of the true skin.
The epithelial lining is much thicker, continuous with the epidermis, and alone
forms the spiral portion of the tube. When the cuticle is carefully removed from
the surface of the cutis, these convoluted tubes of epidermis may be drawn out,
and form nipple-shaped projections on its under surface. According to Kolliker,
a layer of non-striated muscular fibres, arranged longitudinally, is found between
the areolar and epithelial coats cf the ducts of the larger sweat-glands, as in the
axilla, root of the penis, on the labia majora, and around the anus.
The contents of the smaller sweat-glands are quite fluid; but in the larger
glands, the contents are semi-fluid and opaque, and contain a number of coloured
granules, and cells which appear analogous to epithelial cells.
The Tongue.
The tongue is the organ of the special sense of taste. It is situated in the
floor of the mouth, in the interval between the two lateral portions of the body of
the lower jaw. Its base, or root, is directed backwards, and connected with the
OS hyoides by numerous muscles, to the epiglottis by three folds of mucous mem-
brane, which form the glosso-epiglottic ligaments, and to the soft palate and
pharynx by means of the anterior and posterior pillars of the fauces. Its apex
or tip, thin and narrow, is directed forwards against the inner surface of the
lower incisor teeth. The under surface of the tongue, at its back part, is con-
nected with the lower jaw by the Genio-hyo-glossi muscles; from its sides, the
mucous membrane is reflected to the inner surface of the gums; and, in front, a
distinct fold of that membrane, the frajnum linguae, is formed beneath its under
surface.
The tip of the tongue, part of its under surface, its sides, and dorsum, are free.
The dorsum of the tongue is convex, marked along the middle line by a raphe,
which divides it into two symmetrical halves; and this raphe terminates behind,
about half an inch from the base of the organ, a little in front of a deep mucous
follicle, the foramen ccecum. The anterior two-thirds of this surface are rough,
and covered with papillas; the*posterior third is more smooth, and covered by the
projecting orifices of numerous muciparous glands.
The mucous membrane invests the entire extent of the free surface of the
tongue. On the under surface of the organ it is thin and smooth, and may be
N N 2
548
ORGANS OF SENSE.
traced on either side of the fraenum, through the ducts of the submaxillary glands;
and between the sides of the tongue and the lower jaw, through the ducts of the
sublingual glands. On being traced over the borders of the organ, it gradually
275. — Upper Surface of the Tongue.
JFHiform
^ Ji e *
FIG. 276. The .3 hinds cf PAPILL/t magnified
assumes its papillary character; and on the dorsum becomes exceedingly dense,
and gives support to numerous papillae.
The papillae of the tongue are the papillae maximae (circumvallatse), papillae
mediae (fungiformes), and papillae minimae (conicae and filiformes).
The PapillcB maximce (circumvallatse) are of large size, and vary from eight to
fifteen in number. They are situated at the back part of the dorsum of the
tongue, near its root, forming a row on each side, which, running backwards and
inwards, meet in the middle line at the foramen caecum. Each papilla resembles
an inverted cone, the apex of which is attached to the bottom of a cup-shaped
depression of the mucous membrane ; the broad base being exposed upon the
surface, and covered with numerous small papillae. This cup-shaped depression
THE TONGUE.
549
forms a kind of fossa around the papilla, having a circular elevated margin covered
with smaller papillas.
The PapillcB medics, (fungiformes), more numerous than the preceding, are
scattered irregularly over the dorsum of the tongue; but are found chiefly at its
sides and apex. They are easily recognised, among the other papillae, by their
large size, rounded eminences, and deep red colour. They are narrow at their
attachment to the tongue, but broad and rounded at their free extremities, and
covered with secondary papillse.
The PapillcB minimcB (conicaa et filifoi-mes) cover the anterior two-thirds of the
dorsum of the tongue. They are very minute, more or less conical or filiform in
shape, and arranged in lines corresponding in direction with the two rows of the
papillae circumvallatae; excepting at the apex of the organ, where their direction
is transverse. The filiform papillse are of a whitish tint, owing to the thickness
and density of their epithelium; they are covered with numerous secondary
papillge, are firmer and more elastic than the papillae of mucous membrane
generally, and often enclose minute hairs.
Structure of the Papilla. The papillae, in structure, resemble those of the
cutis, consisting of a cone-shaped projection of homogeneous tissue, covered with a
thick layer of squamous epithelium, and contain one or more capillary loops,
amongst which nerves are distributed in great abundance. In the papillae cir-
cumvallatae, the nerves are numerous and of large size; in the papillae fungiformes
they are also numerous, and terminate in a plexiform network, from which brush-
like branches proceed; in the papillae filiformes, their mode of termination is
uncertain.
Besides the papillae, the mucous membrane of the tongue is pi-ovided with
numerous follicles and glands.
The Follicles are found scattered over its entire surface, but are especially
numerous between the papillae circumvallatae and the epiglottis.
The Mucous Glands (lingual), similar in structure to the labial and buccal,
are found chiefly beneath the mucous membrane of the posterior third of the
dorsum of the tongue. There is a small group of these glands beneath the tip of
the tongue, a few along the borders of the organ, and some in front of the circum-
vallate papillae projecting into the muscular substance. Their ducts open either
upon the surface, or into the depressions around the large papillae.
The tongue consists of two symmetrical halves, separated from each other, in
the middle line, by a fibrous septum. Each half is composed of muscular fibres
arranged in various directions, containing much interposed fat, and supplied
by vessels and nerves: the entire organ is invested by mucous membrane, and a
submucous fibrous stratum. The latter membrane invests the greater part of the
surface of the tongue, and into it the muscular fibres are inserted that pass to the
surface. It is thicker behind than in front, and is continuous with the sheaths of
the muscles attached to it.
The Fibrous Septum consists of a vertical layer of fibrous tissue, extending
throughout the entire length of the middle line of the tongue, from the base to
the apex. It is thicker behind than in front, and occasionally contains a small
fibro-cartilage, about a quarter of an inch in length. It is well displayed by
making a vertical section through the organ. Another strong fibrous lamina,
termed the hyo-glossal membrane, connects the under surface of the base of the
tongue to the body of the hyoid bone. This membrane receives, in front, some of
the fibres of the Genio-hyo-glossi.
Each half of the tongue consists of extrinsic and intrinsic muscles. The former
have been already described; they are the Hyo-glossus, Genio-hyo-glossus, Stylo-
glossus, Palato-glossus, and part of the Superior constrictor. The intrinsic mus-
cles are the Superior longitudinal, Inferior longitudinal, and Transverse.
The Superior Longitudinal Fibres {lingualis superficialis) form a superficial
stratum of oblique and longitudinal fibres on the upper surface of the organ,
beneath the mucous membrane, and extend from the apex backwards to the hyoid
550
ORGANS OF SENSE.
bone, the individual fibres being attached in their course to the submucous and
glandular structures.
The Inferior Longitudinal Fibres are formed by the Lingualis muscle, already-
described (p. 2I0).
The Transverse Fibres are placed between the two preceding layers; they are
intermixed with a considerable quantity of adipose substance, and form the chief
part of the substance of the organ. They are attached internally to the median
fibrous septuni ; and, passing outwards, the posterior ones taking an arched course,
are inserted into the dorsum and margins of the organ, intersecting the other
muscular fibres.
The Arteries of the tongue are supplied from the lingual, the facial, and
ascending pharyngeal.
The Nerves of the tongue are three in number in each half: the gustatory
branch of the fifth, which is distributed to the papillae at the fore part and sides
of the tongue; the lingual branch of the glosso-pharyngeal, which is distributed
to the mucous membrane at the base and side of the tongue, and to the papillae
circumvallatEe ; and the hypo-glossal nerve, which is distributed to the muscular
substance of the tongue. The two former are nerves of common sensation and
of taste; the latter is the motor nerve of the tongue.
The Nose.
The Nose is the special organ of the sense of smell: by means of the peculiar
properties of its nerves, it protects the lungs from the inhalation of deleterious
gases, and assists the organ of taste in discriminating the properties of food.
The organ of smell consists of two parts, one external, the nose; the other
internal, the nasal fossas.
The Nose is the most anterior and prominent part of the organ of smell. It is
of a triangular form, directed vertically downwards, and projects from the centre
of the face, immediately above the upper lip. Its summit, or root, is connected
directly with the forehead. Its inferior part, the base of the nose, presents two
elliptical orifices, the nostrils, separated from each other by an antero-posterior
septum, the columna. The margins of these orifices are provided with a number
377. — Cartilages of the Nose.
Seen from helouf
1 om r T atea-al (7.
Side Vie'U/-
of stilF hairs, or vibrissce, which arrest the passage of foreign substances carried
with the current of air intended for respiration. The lateral surfaces of
the nose, form, by their union, the dorsum, the direction of which varies con-
THE NOSE.
551
siderably in different individuals. The dorsum terminates below in a rounded
eminence, the lobe of the nose.
The nose is composed of a framework of bones and cartilages, the latter l)eing
slightly acted upon by certain muscles. It is covered externally l)y the integu-
ment, internally by mucous membrane, and supplied with vessels and nerves.
The hony frameivork occupies the upper part of the organ: it consists of the
nasal bones, and the nasal processes of the superior maxillary.
The cartilaginous framework consists of five pieces, the two upper, and the
two lower lateral cartilages, and the cartilage of the septum.
The upper lateral cartilages are situated below the free margin of the nasal
bones: each cartilage is flattened, and triangular in shape. Its anterior margin is
thicker than the posterior, and connected with the fibro-cartilage of the septum.
Its posterior margin is attached to the nasal process of the superior maxillary
and nasal bones. Its inferior margin is connected by fibrous tissue with the
lower lateral cartilage : one surface is turned outwards, the other inwards
towards the nasal cavity.
The loioer lateral cartilages are two thin, flexible plates, situated immediately
below the preceding, and curved
in such a manner as to form the 278.— Bones and Cartilages of Septum of Nose.
inner and outer walls of each Right Side.
orifice of the nostril. The por-
tion which forms the inner wall,
thicker than the rest, is loosely
connected with the same part of
the opposite cartilage, and forms
a small part of the columna. Its
outer extremity, free, rounded,
and projecting, forms, with the
thickened integument and sub-
jacent tissue, the lobe of the
nose. The part which forms the
outer wall is curved to correspond
with the ala of the nose: it is
oval and flattened, narrow behind,
where it is connected with the
nasal process of the superior
maxilla by a tough fibrous
membrane, in which is found
three or four small cartilaginous plates (sesamoid cartilages), cartilagines minores.
Above, it is connected to the lateral fibro-cartilage and front part of the cartilage
of the septum; below, it is separated from the margin of the nostril by dense
cellular tissue; and in front, it forms, with its fellow, the prominence of the tip
of the nose.
The cartilage of the septum is somewhat triangular in form, thicker at its
margins than at its centre, and completes the separation between the nasal fossaj
in front. Its anterior margin, thickest above, is connected from above down-
wards with the nasal bones, the front part of the two upper lateral cartilages, and
the inner portion of the lower lateral cartilages. Its posterior margin is con-
nected with the perpendicular lamella of the ethmoid; its inferior margin with
the vomer and palate processes of the superior maxillary bones.
These various cartilages are connected to each other, and to the bones, by a
tough fibrous membrane, the perichondrium, which allows the utmost facility of
movement between them.
The Muscles of the Nose are situated immediately beneath the integument:
they are (on each side) the Pyramidalis nasi, the Levator labii superioris al^que
nasi, the Dilator naris, anterior and posterior, the Compressor nasi, the Compressor
narium minor, and the Depressor alas nasi. (See p. 195)-
552 ORGANS OF SENSE.
The Integument covering the dorsum and sides of the nose is thin, and loosely
connected with the subjacent parts; but where it forms the tip, or lobe, and the
alge of the nose, it is thicker, and more firmly adherent. It is furnished with a
large number of sebaceous follicles, the orifices of which are usually very
distinct.
The Mucous Membrane, lining the interior of the nose, is continuous with the
skin externally, and with that which lines the nasal foss^ within.
The Arteries of the Nose are the lateralis nasi, from the facial, and the nasal
artery of the septum, from the superior coronary, which supplies the alse and
Beptum; the sides and dorsum being supplied from the nasal branch of the
ophthalmic and infra-orbital.
The Veins of the Nose terminate in the facial and ophthalmic.
The Nerves of the Nose are branches from the facial, infra-orbital, and infra-
trochlear, and a filament from the nasal branch of the ophthalmic.
Nasal Foss^.
The nasal fossEe are two irregular cavities, situated in the middle of the face,
and extending from before backwards. They open in front by the two anterior
nares, and terminate in the pharynx, behind, by the posterior nares. The boun-
daries of these cavities, and the openings which are connected with them, as they
exist in the skeleton, have been already described (p. 65).
The Mucous Metnhrane lining the nasal fossae is called pituitary, from the
nature of its secretion; or Schneiderian, from Schneider, the first anatomist who
showed that the secretion proceeded from the mucous membrane, and not, as was
formerly imagined, from the brain. It is intimately adherent to the periosteum,
or perichondrium, over which it lies. It is continuous externally with the skin,
through the anterior nares, and with the mucous membrane of the pharynx,
through the posterior nares. From the nasal fossae its continuity may be traced
with the conjunctiva, through the nasal duct and lachrymal canals; with the
lining membrane of the tympanum and mastoid cells, through the Eustachian
tube; and with the frontal, ethmoidal, and sphenoidal sinuses, and the antrum
maxillare, through the several openings in the meatuses. The mucous membrane
is thickest, and most vascular, over the turbinated bones, especially the inferior;
from which circumstance, these bones in their recent state appear longer and more
prominent than in the skeleton. It is also thick over the septum; but, in the
intervals between the spongy bones, and on the floor of the nasal fossae, it is very
thin. Where it lines the various sinuses and the antrum maxillare, it is thin and
pale.
The surface of the membrane is covered with a layer of epithelium, thicker
and non-ciliated at the upper part of the nasal fossae, corresponding with the
distribution of the olfactory nerve, but ciliated throughout the rest of its extent,
excepting near the aperture of the nares.
This membrane is also provided with a nearly continuous layer of branched
mucous glands, the ducts of which open upon its surface. They are most nume-
rous at the middle and back parts of the nasal fossae, and largest at the lower and
back part of the septum.
Owing to the great thickness of this membrane, the nasal foss^ are much
narrower, and the turbinated bones, especially the lower ones, appear larger, and
more prominent, than in the skeleton. From the same circumstance, also, the
various apertures communicating with the meatus, are either narrowed or com-
pletely closed.
In the superior meatus, the aperture of communication with the posterior
ethmoidal cells is considerably diminished in size, and the spheno-j)alatine foramen
completely covered in.
In the middle meatus, the opening of the infundibulum is partially hidden by
a projecting fold of mucous membrane, and the orifice of the antrum is contracted
to a small circular aperture, much narrower than in the skeleton.
NASAL FOSS^.
553
In the inferior meatus, the orifice of the nasal duct is partially hidden by
either a single or double valvular mucous fold, and the anterior palatine canal
either completely closed in, or a tubular cul-de-sac of mucous membrane is con-
tinued a short distance into it.
In the roof, the opening leading to the sphenoidal sinuses is narrowed, and the
apertures in the cribriform plate of the ethmoid completely closed in.
The Arteries of the Nasal Fossce, are the anterior and posterior ethmoidal,
from the ophthalmic, which supply the ethmoidal cells, frontal sinuses and roof
of the nose; the spheno-palatine,
from the internal maxillary, 279.— Nerves of Septum of Nose. Eight Side.
which supplies the mucous mem-
brane covering the spongy bone,
the meatuses, and septum; and the
alveolar branch of the internal
maxillary, which supplies the
lining membrane of the antrum.
The ramifications of these vessels
form a close, plexiform network,
beneath and in the substance of
the mucous membrane.
The Veins of the Nasal Fossce
form a close network beneath the
mucous membrane. They pass,
some with the veins accompany-
ing the spheno-palatine artery
through the spheno-palatine fora-
men; and others, through the
alveolar branch, join the facial vein; some accompany the ethmoidal arteries,
and terminate in the ophthalmic vein; and lastly, a few communicate with the
veins in the interior of the skull, through the foramina in the cribriform plate of
the ethmoid bone.
The Nerves are the olfactory, the nasal branch of the ophthalmic, filaments
from the anterior dental branch of the superior maxillary, the Vidian, naso-
palatine, descending anterior palatine, and spheno-palatine branches of Meckel's
ganglion.
The Olfactory, the special nerve of the sense of smell, is distributed over the
upper third of the septum, and over the surface of the superior and middle spongy
bones.
The Nasal Branch of the Ophthalmic distributes filaments to the upper and
anterior part of the septum, and outer wall of the nasal fossag.
Filaments from the Anterior Dental Branch of the Superior Maxillary supply
the inferior meatus and inferior turbinated bone.
The Vidian Nerve supplies the upper and back part of the septum, and supe-
rior spongy bone: and the upper anterior nasal branches from the spheno-palatine
ganglion, have a similar distribution.
The Naso-Palatine Nerve supplies the middle of the septum.
The Larger, or Anterior Palatine Nerve, supplies the middle and lower
spongy bones.
The Eye.
The eyeball is contained in the cavity of the orbit. In this situation it is
securely protected from injury, whilst its position is such as to ensure the most
extensive range of sight. It is acted upon by numerous muscles, by which it is
capable of being directed to any part, supplied by numerous vessels and nerves,
and is additionally protected in front by several appendages, such as the eyebrow,
eyelids, etc.
The eyeball is spherical in form, having the segment of a smaller and more
554
ORG-ANS OF SENSE.
prominent sphere engrafted upon its anterior part. It is from this circumstance, that
the antero-posterior diameter of the eyeball, which measures about an inch, exceeds
the transverse diameter by about a line. The segment of the larger sphere, Avhich
forms about five-sixths of the globe, is opaque, and formed by the sclerotic, the
tunic of protection to the eyeball; the smaller sphere, which forms the remaining
sixth, is transj)arent, and formed by the cornea. The axes of the eyeballs are
nearly parallel, and do not correspond to the axes of the orbits, which are directed
outwards. The optic nerves follow the direction of the axes of the orbits, and
enter the eyeball a little to their inner or nasal side. The eyeball is composed of
several investing tunics, and of fluid and solid refracting media, called humours.
The tunics are three in number:
1. Sclerotic and Cornea.
2. Choroid, Iris, and Ciliary "Processes.
3. Retina.
The refracting media, or humours, are also three :
Aqueous. Crystalline (lens) and Capsule.
Vitreous.
The sclerotic and cornea form the most external tunic of the eyeball; they are
essentially fibrous in structure, the sclerotic being opaque and forming the posterior
five-sixths of the globe, the cornea, which forms the remaining sixth, being
transparent.
The Sclerotic {(TKXrjpo^, hard) (fig. 280) has received its name from its extreme
density and hardness; it is a firm unyielding fibrous membrane, serving to main-
280. — A Vertical Section of the Eyeball (Enlarged).
Sclerotic -^ — ^^^■■^^^^~'~~ ^"^' — Tp.ndnm of RECTUS
Clioroid
Jietlna <C-^
JLyaZold Me mimne
aiirtru 2£ufiele
& I,l^ament
•Circular Sinus
Canal of Petit
tain the peculiar form of the globe. It is mvich thicker behind than in front.
The external surface is of a white colour, and quite smooth, except at the points
where the Recti and Obliqui muscles are inserted into it, and covered, for part of
its extent, by the conjunctival membrane; hence the whiteness and brilliancy of
the front of the eyeball. Its i7iner surface is stained of a brown colour, marked
by grooves, in which are lodged the ciliary nerves, and connected by an exceed-
SCLEROTIC; CORNEA.
555
ingly fine cellular tissue [lamina fusca) with the outer surface of the choroid.
Behind, it is pierced by the optic nerve a little to its inner or nasal side, and is
continuous with its fibrous sheath, which is derived from the dura mater. At
the point where the optic nerve passes through the sclerotic, this membrane forms
a thin cribriform lamina (the lamina cribrosa); the minute orifices in this part
serve for the transmission of the nervous filaments, and the fibrous septa dividing
them from one another are continuous with the membranous processes which
separate the bundles of nerve-fibres. One of these openings, larger than the rest,
occupies the centre of this lamella; it is called i\\Q porus opticus, and transmits
the arteria centralis retinae to the interior of the eyeball. Around the cribriform
lamella are numerous smaller apertures for the transmission of the ciliary vessels
and nerves. In front, this membrane is continuous with the cornea by direct
continuity of tissue; but the opaque sclerotic overlaps it rather more on the outer
than upon its inner surface.
Structure. The sclerotic is formed of white fibrous tissue intermixed with fine
elastic fibres, and fusiform nucleated cells. These are aggregated into bundles,
which are arranged chiefly in a longitudinal direction. It yields gelatin on
boiling. Its vessels are not numerous, the capillaries being of small size, uniting
at long and wide intervals. The existence of nerves in it is doubtful.
The Cornea is the projecting transparent part of the external tunic of the eye-
ball, and forms the anterior sixth of the globe. Its form is not quite circular,
being a little broader in the transverse than in the vertical direction, in conse-
quence of the sclerotic overlapping the margin above and below. It is concavo-
convex, and projects forwards from the sclerotic in the same manner that a watch-
glass does from its case. Its degree of curvature varies in different individuals,
and in the same individual at different periods of life, being more prominent in
youth than in advanced life, when it becomes flattened. This difference in the
greater or smaller convexity of the cornea influences considerably the refractive
power of the eye, and is the chief cause of the long or short sight peculiar to
different individuals. It is of uniform thickness throughout, but its posterior sur-
face is perfectly circular in outline, and exceeds the anterior surface slightly in
extent, from the latter being overlapped by the sclerotic.
Structure. The cornea consists of five layers: namely, of a thick central fibi'ous
part, the cornea proper ; in front of this is the anterior elastic lamina, covered by
the conjunctiva; behind, the posterior elastic lamina, covered by the lining mem-
brane of the anterior chamber of the eyeball.
The proper substance of the cornea is fibrous in structure, tough, unyielding,
perfectly transparent, and continuous with the sclerotic, with which it is in struc-
ture identical. The anastomosing fusiform cells of which it is composed are
arranged in superimposed flattened laminas, at least sixty in number, all of which
have the same direction, the contiguous laminse becoming united at frequent
intervals. If the relative position of the component parts of this tissue is in any
way altered, either by pressure or by an increase of its natural tension, it imme-
diately presents an opaque milky appearance. The interstices between the lamina
are tubular, and usually contain a small amount of perfectly clear transparent
fluid.
The anterior and posterior elastic lamince, which invest the proper structure
of the cornea behind and in front, present an analogous structure. They consist
of a hard, elastic, and perfectly transparent homogeneous membrane, of extreme
thinness, which is not rendered opaque by either water, alcohol, or acids. This
membrane is intimately connected by means of a fine cellular web to the proper
substance of the cornea both in front and behind. Its most remarkable property
is its extreme elasticity, and the tendency which it presents to curl up, or roll
upon itself, with the attached surface innermost, when separated from the proper
substance of the cornea. Its use appears to be (as suggested by Dr. Jacob),
' to preserve the requisite permanent correct curvature of the flaccid cornea
proper.'
556
ORGANS OF SENSE.
The conjunctival epithelium, which covers the front of the anterior elastic
lamina, consists of two or three layers of transparent nucleated cells, the deepest
being of an oblong form and placed perpendicular to the surface, the superficial
ones more flattened.
The epithelial lining of the aqueous chamber covers the posterior surface of the
posterior elastic lamina. It consists of a single layer of polygonal transparent
nucleated cells, similar to those found lining other serous cavities.
Arteries and Nerves. The cornea is a non-vascular structure, the capillary
vessels terminating in loops at its circumference. Lymphatic vessels have not
as yet been demonstrated in it. The nerves are numerous, twenty or thirty in
number: they are derived from the ciliary nerves, and enter the laminated sub-
stance of the cornea. They ramify throughout its substance in a delicate net-
work.
Dissection. In order to separate the sclerotic and cornea, so as to expose the second
tunic, the eyeball should be immersed in water contained in a small vessel. A fold of
the sclerotic near its anterior part being then pinched up, an operation not easily per-
formed from the extreme tension of the membrane, it should be divided with a pair
of blunt-pointed scissors. As soon as the choroid is exposed, the end of a blow-pipe
should be introduced into the orifice, and a stream of air forced into it, so as to sepa-
rate the slight cellular connection between the sclerotic and choroid. The sclerotic
should now be divided around its entire circumference, and may be removed in separate
portions. The front segment being now drawn forwards, the handle of the scalpel should
be pressed gently against it at its connection with the iris, and these being separated,
a quantity of perfectly transparent fluid will escape; this is the aqueous humour. In
the course of this dissection, the ciliary nerves may be seen lying in the loose cellular
tissue between the choroid and sclerotic, or contained in delicate grooves on the inner
surface of the latter membrane.
281. — The Choroid and Iris (enlarged).
Second Tunic. This is formed by the choroid behind; the iris and ciliary pro-
cesses in front; and by the ciliary ligament, and Ciliary muscle, at the point of
junction of the sclerotic and cornea.
The choroid is the vascular and pigmentary tunic of the eyeball, investing the
CHOROID.
557
posterior five- sixths of the globe, and extending as far forwards as the cornea;
the ciliary processes being appendages of the choroid developed from its inner
surface in front. The iris is the circular- shaped muscular septum, which hangs
vertically behind the cornea, presenting in its centre a large circular aperture,
the pupil. The ciliary ligament and Ciliary muscle form the white ring observed
at the point where the choroid and iris join with each other, and with the sclerotic
and cornea.
The Choroid is an extremely thin membrane, highly vascular, of a dark brown,
or chocolate colour, which invests the posterior five- sixths of the central part of
the globe. It is pierced behind by the optic nerve, and terminates in front at the
ciliary ligament, where it bends inwards, and forms on its inner surface a series
of folds, or plaitings, the ciliary processes. It is thicker behind than in front.
Externally, it is connected by a fine cellular web {membrana fused) with the inner
surface of the sclerotic. Its inner surface is smooth, and lies in contact with the
the retina. The choroid is composed of three layers, external, middle, and
internal.
282. — The Veins of
(enlarged).
The external layer consists of the larger branches of the short ciliary arteries,
which run forwards between the veins before they bend downwards to terminate
on the inner surface. This coat consists, however, principally of veins, which
are disposed in curves, hence their name, vence vorticosce. They converge to four
or five equidistant trunks, which pierce the sclerotic midway between the margin
of the cornea and the entrance of the optic nerve. Interspersed between the
vessels, are lodged dark star-shaped pigment cells, the fibrous offsets from which,
communicating with similar branchings from neighbouring cells, form a delicate
network, which, towards the inner surface of the choroid, loses its pigmentary
character.
The middle layer consists of an exceedingly fine capillary plexus, formed by the
short ciliary vessels, and is known as the tunica Ruyschiana. The network is
exceedingly close, and finer at the hinder part of the choroid than in front. About
half an inch behind the cornea, its meshes become larger, and are continuous
with those of the ciliary processes.
The internal, or pigmentary layer, is an exceedingly delicate membrane,
consisting of a single layer of hexagonal, nucleated cells, loaded with pigment
granules, and applied to each other so as to resemble a tesselated pavement. Each
cell contains a nucleus, and is filled with grains of pigment, which are in greater
abundance at the circumference of the cell. In perfect albinos this epithelium
558
ORGANS OF SENSE.
contains no pigment, and none is present in the star-sliaped cells found in the
other layers of the choroid.
The ciliarj processes should be next examined : they may be exposed, either by detach-
ing the iris from its connection with the ciliary ligament, or by making a transverse
section of the globe, and examining them from behind.
Z83. — The Arteries of the Choroid and Iris.
The Sclerotic has been mostly removed. (Enlarged)
Ciliary A?
Anterior
CilvaryA
The Ciliary processes are formed by the plaiting or folding inwards of the
middle and internal layers of the choroid, at its anterior margin, and are received
betvp^een corresponding foldings of the suspensory ligament of the lens, thus
establishing a communication between the choroid and inner tunic of the eye.
They are arranged in a circle, behind the iris, around the margin of the lens.
They vary between sixty and eighty in number, lie side by side, and may be
divided into large and small; the latter, consisting of about one-third of the entire
number, are situated in the spaces between the former, but without regular alter-
nation. The larger processes are each about one-tenth of an inch in length,
and hemispherical in shape, their periphery being attached to the ciliary ligament,
and continuous with the middle and inner layers of the choroid: the opposite
margin is free, and rests upon the circumference of the lens. Their anterior sur-
face is turned towards the back of the iris, with the circumference of which it is
continuous. The posterior surface is closely connected with the suspensory
ligament of the lens.
Structure. The ciliary processes are similar in structure to the choroid: the
vessels are larger, having chiefly a longitudinal direction. Externally they are
covered with several layers of pigment cells; the component cells are small,
rounded, and full of pigment granules.
The Iris {iris, a rainbow,) has received its name from the varied colour it pre-
sents in different individuals. It is a thin, circular- shaped, contractile curtain,
suspended in the aqueous humour behind the cornea, and in front of the lens,
being perforated at the nasal side of its centre by a circular aperture for the
transmission of the light, the pupil. By its circumference it is intimately
connected with the choroid ; externally to this is the ciliary ligament, by
which it is connected to the sclerotic and cornea; its inner edge forms the
margin of the pupil; its surfaces are flattened, and look forwards and backwards,
the anterior surface towards the cornea, the posterior towards the ciliaiy processes
and lens. The anterior surface is variously coloured in different individuals, and
marked by lines which converge towards the pupil. The posterior surface is of a
IRIS; CILIARY LIGAMENT. 559
deep purple tint, from being covered by dark pigment; it is hence named uvea,
from its resemblance in colour to a ripe grape.
Structure. The iris is composed of a fibrous stroma, muscular fibres, and pig-
ment cells.
The fibrous stroma consists of fine, delicate bundles of fibrous tissue, which
have a circular direction at the circumference: but the chief mass radiate towards
the pupil. They form, by their interlacement, a delicate mesh, in which the pig-
ment cells, vessels, and nerves, are contained.
The muscular fibre is involuntary, and consists of circular and radiating
fibres. The circular fibres (sphincter of the pupil), surround the margin of the
pupil on the posterior surface of the iris, like a sphincter, forming a narrow band,
about one-thirtieth of an inch in width; those near the free margin being closely
aggregated; those more external are separated somewhat, and form less com-
plete circles. The radiating fibres (dilator of the pupil), converge from the
circumference towards the centre, and blend with the circular fibres near the
margin of the pupil. The circular fibres contract the pupil, the radiating fibres
dilate it.
The pigment cells are found in the stroma of the iris, and also as a distinct layer
on its anterior and posterior surfaces. In the stroma, the cells are ramified, and
contain yellow or brown pigment, according to the colour of the eye. On the
front of the iris, there is a single layer of oval or rounded cells, with branching
offsets. On the back of the iris, there are several layers of small, round cells,
filled with dark pigment. This layer is continuous with the pigmentary covering
of the ciliary processes.
The arteries of the iris are derived from the long and anterior ciliary, and
from the vessels of the ciliary processes.
Membrana Pupillaris. In the fcetus, the pupil is closed by a delicate, trans-
parent vascular membrane, the membrana pupillaris, which divides the space in
which the iris is suspended into two distinct chambers. This membrane contains
numerous minute vessels, continued from the margin of the iris to those on the
front part of the capsule of the lens. These vessels have a looped arrangement,
converging towards each other without anastomosing. Between the seventh and
eighth month, this membrane commences to disappear, by its gradual absorption
from the centre towards the circumference, and, at birth, only a few fragments
remain. Sometimes it remains permanent, and produces blindness.
The Ciliary Ligament is a narrow ring of circular fibres, about one-fortieth of
an inch thick, and of a whitish colour, which serves to connect the external and
middle tunics of the eye. It is placed around the circvimference of the iris, at
its point of connection with the external layer of the choroid, the cornea, and
sclerotic. Its component fibres are delicate, and resemble those of elastic tissue.
At its point of connection with the sclerotic, a minute canal is situated between
the two, called the sinus circularis iridis.
The Ciliary 3Iuscle (Bowman) consists of unstriped fibres: it forms a greyish,
semitransparent, circular band, about one-eighth of an inch broad, on the outer
surface of the fore part of the choroid. It is thickest in front, and gradually
becomes thinner behind. Its fibres are soft, of a yellowish-white colour, longitu-
dinal in direction, and arise at the point of junction of the cornea and sclerotic.
Passing backwards, they are attached to the choroid, in front of the retina, and
correspond by their inner surface to the plicated part of the former membrane.
Mr. Bowman supposes that this muscle is so placed as to advance the lens, by
exercising compression on the vitreous body, and by drawing the ciliary processes
towards the line of junction of the sclerotic and cornea, and by this means to
adjust the eye to the vision of near objects.
The Retina may be easily exposed by carefully removing the choroid from its
external surface. The retina is the delicate nervous membrane, upon the surface
of which the images of external objects ai-e received. Its outer surface is in
contact with the pigmentary layer of the choroid; its inner surface with the
56o
ORGANS OF SENSE.
vitreous body. Behind, it is continuous with the optic nerve ; and in front
extends nearly as far forwards as the ciliary ligament, where it terminates by a
jagged margin, the ora serrata. It is soft, transparent, of a pinkish-grey colour
in the fresh state, and gradually diminishes in thickness from behind forwards.
284. — The Arteria Centralis Eetinse, Yellow Spot, &c.
the Anterior half of the Eyeball being removed. (Enlarged).
In the centre of the posterior part of the globe, the retina prepents a yellow spot,
limbus luteus {Soemmering), of a circular form, and having a central depression,
fovea centralis. The retina in this situation is exceedingly thin; so much so,
that the dark colour of the choroid is distinctly seen through it; so that it pre-
sents more the appearance of a foramen, and hence the name 'foramen of Soemme-
ring' at first given to it. It exists only in man, the quadrumana, and some
saurian reptiles. About ^V ^^ ^^ inch to the inner side of the yellow spot, is the
entrance of the optic nerve; and the arteria centralis retinas piercing its centre.
Structure. The retina is composed of three layers, together with blood-vessels.
External or columnar layer (Jacob's membrane).
Middle or granular layer.
Internal or nervous layer.
The blood-vessels do not form a distinct layer; they ramify in the substance of
the internal layer.
The External, or Jacob's Membrane, is exceedingly thin, and can be detached
from the external surface of the retina by the handle of the scalpel, in the form of
a flocculent film. It is thicker behind than in front, and consists of rod-like
bodies of two kinds: i. Columnar rods, solid, nearly of uniform size, and arranged
perpendicular to the surface. 2. Bulbous particles, or cones, which are inter-
spersed at regular intervals among the former; these are conical or flask-shaped,
their broad ends resting upon the granular layer, the narrow pointed extremity
being turned towards the choroid; they are not solid, like the columnar rods, but
consist of an external membrane with fluid contents. By their deep ends, both
kinds are joined to the fibres of MUller.
The Middle, or Granular Layer, forms about one-third of the entire thickness
of the retina. It consists of two laminae of rounded or oval nuclear particles,
separated from each other by an intermediate layer, which is transparent, finely
fibrillated, and contains no blood-vessels. The outermost layer is the thickest,
and its constituent particles are globular. The innermost layer is the thinnest;
RETINA. 561
its component particles are flattened, looking like pieces of money seen edgeways;
hence it has been called by Bowman, the nummular layer.
The Internal, or Nervous Layer, consists of nerve-fibres and nerve-cells. The
expansion of the optic nerve forms a thin, semi-transparent, filjrous membrane,
thicker behind than in front. It is composed of nerve-fibres collected into bun-
dles, which communicate, forming a delicate net, with flattened elongated meshes.
The nerve-fibres which form this layer, differ from the fibres of the optic nerve in
this respect: they lose their dark outline, and their tendency to become varicose;
and consist only of the central part, or axis, of the nerve tubes. The mode of
termination of the nerve-fibres is unknown. Recent observers have stated, that
some of the nerve fibres are continuous with the caudate prolongations of the
nerve-cells external to the fibrous layer. The nerve-cells are jDlaced on the outer
side of the fibrous layer; they are round or pear-shaped transparent cells, nu-
cleated, with granular contents, furnished with caudate prolongations, some of
which join the fibres of the optic nerve, whilst others are directed externally
towards the granular layer.
An extremely thin and delicate structureless membrane lines the inner surface
of the retina, and separates it from the vitreous body; it is called the membrana
limitans.
The Radiating Fibres of the retina, described by Heinrich Miiller, consist of
extremely fine fibrillated threads, which are connected externally with each of the
rods of the columnar layer, of which they appear to be direct continuations; and,
passing through the entire substance of the retina, are united to the outer surface
of the membrana limitans. Li their course through the retina, they become con-
nected with the nuclear particles of the granular layer, and give ofi^ branching
processes opposite its innermost lamina; as they approach the fibrous expansion
of the optic nerve, they are collected into bundles, which pass through the areolae
between its fibres, and are finally attached to the inner surface of the membrana
limitans, where each fibre terminates in a triangular enlargement.
The Arteria Centralis Retince and its accompanying vein pierce the optic
nerve, and enter the globe of the eye through the porus ojiticus. It immediately
divides into four or five branches, which at first run between the hyaloid mem-
brane and the nervous layer; but they soon enter the latter membrane, and form
a close capillary network in its substance. At the ora serrata they terminate in
a single vessel, which bounds the terminal margin of the retina.
The structure of the retina at the yellow spot, presents some modifications.
Jacob's membrane is thinner, and of its constituents only the cones are present;
but they are small, and more closely aggregated than in any other part. The
granular layer is absent over the fovea centralis. Of the two elements of the
nervous layer, the nerve-fibres extend only to the circumference of the spot; but
the nerve-cells cover its entire surface. The radiating fibres are found at the
circumference, and here only extend to the inner strata of the granular layer.
Of the capillary vessels, the larger branches pass around the spot; but the smaller
capillaries meander through it. The colour of the spot appears to imbue all the
layers except Jacob's membrane ; it is of a rich yellow, deepest towards the
centre, and does not appear to consist of pigment-cells, but resembles more a
staining of the constituent parts.
Humours of the Eye.
The Aqueous Humour completely fills the anterior and posterior chambers of
the eyeball. It is small in quantity (scarcely exceeding, according to Petit, four
or five grains in weight), has an alkaline reaction, in composition is little more
than water, less than one-fiftieth of its weight being solid matter, chiefly chloride
of sodium.
The anterior chamber is the space bounded in front by the cornea; behind, by
the front of the iris and ciliary ligament.
o o
562 ORGANS OF SENSE.
The posterior chamber, smaller than the anterior, is bounded in front by the
iris; behind, by the capsule of the lens and its suspensory ligament, and the
ciliary processes.
In the adult, these two chambers communicate through the pupil; but in the
foetus before the seventh month, when the pupil is closed by the membrana pupil-
laris, the two chambers are quite separate.
It has been generally supposed that the two chambers are lined by a distinct
membrane, the secreting membrane of the aqueous humour, analogous in struc-
ture to that of a serous sac. Only an epithelial covering can, however, be found
on the posterior surface of the cornea. That the two chambers do, however,
secrete this fluid separately, is shown from its being found in both spaces before
the removal of the membrana pupillaris. It is probable that the parts concerned
in the secretion of the fluid, are the posterior surface of the cornea, both surfaces
of the iris, and the ciliary processes.
Vitreous Body.
The Vitreous Body forms about four-fifths of the entire globe. It fills the
concavity of the retina, and is hollowed in front for the reception of the lens and
its capsule. It is perfectly transparent, of the consistence of thin jelly, and
consists of an albuminous fluid enclosed in a delicate, transparent membrane,
the hyaloid. This membrane invests the outer surface of the vitreous body; it
is intimately connected in front with the suspensory ligament of the lens; and is
continued into the back part of the capsule of the lens. It has been supposed, by
Hannover, that from its inner surface numerous thin lamellfe are prolonged
inwards in a radiating mannei', forming spaces in which the fluid is contained.
In the adult, these lamellae cannot be detected even after careful microscopic ex-
amination; but in the foetus a peculiar fibrous texture pervades the mass, the fibres
joining at numerous points, presenting minute nuclear granules at their point of
junction. The fluid from the vitreous body resembles nearly pure water ; it
contains, however, some salts, and a little albumen.
In the fcetus, the centre of the vitreous humour presents a tubular canal,
through which a minute artery passes along the vitreous body to the capsule of
the lens. In the adult, no vessels penetrate its substance; so that its nutrition
must be carried on by the vessels of the retina and ciliary processes, situated upon
its exterior.
Crystalline Lens and its Capsule.
The Crystalline Lens, enclosed in its Capsule, is situated immediately behind
the pupil, in front of the vitreous body, and surrounded by the ciliary processes,
which slightly overlap its margin.
The Capsule of the Lens is a transparent, highly elastic, and brittle membrane,
which closely surrounds the lens. It rests, behind, in a depression in front of
the vitreous body: in front, it forms part of the posterior chamber of the eye;
and it is retained in its position chiefly by the suspensory ligament of the lens.
The capsule is much thicker in front than behind, structureless in texture; and
when ruptured, the edges roll up with the outer surface innermost, like the elastic
laminse of the cornea. The lens is connected to the inner surface of the capsule
by a single layer of transparent, polygonal, nucleated cells. These, after death,
absorb moisture from the fluids of the eye; and, breaking down, form the liquor
Morgagni.
In the fcetus, a small branch from the arteria centralis retinas runs forwards, as
already mentioned, through the vitreous humour to the posterior part of the cap-
sule of the lens, where its branches radiate and form a plexiform network, which
covers its surface, and are continuous around the margin of the capsule, with the
vessels of the pupillary membrane, and with those of the iris. In the adult, no
vessels enter its substance.
The Lens is a transparent, double convex body, the convexity being greater on
THE LENS. 563
tiie posterior, than on the anterior, surface. It measures about a third of an inch
in the transverse diameter, and about one-fourth in the antero-posterior. It con-
sists of concentric layers, of which the external,
in the fresh state, are soft and easily detached; 285. — The Crystalline Lens,
those beneath are firmer, the central ones form- hardeiied and divided,
ing a hardened nucleus. These laminaB are best ^ & •/
demonstrated by boiling, or immersion in alcohol.
The same re-agents demonstrate that the lens
consists of three triangular segments, the sharp
edges of which are directed towards the centre,
the bases towards the circumference. The la-
minse consist of minute parallel fibres, which are
united to each other by means of wavy margins,
the convexities upon one fibre fitting accurately
into the concavities of the adjoining fibre.
The changes produced in the lens by age, are
the following:
In the fcetus, its form is nearly spherical, its colour of a slightly reddish tint,
not perfectly transparent, and so soft as to readily break down on the slightest
pressure.
In the adult, the posterior surface is more convex than the anterior, it is
colourless, transparent, and firm in texture.
In old age, it becomes flattened on both surfaces, slightly opaque, of an amber
tint, and increases in density.
The suspensory ligament of the lens is a thin, transparent membranous struc-
ture, placed between the viti'eous body and the ciliary processes of the choroid:
it connects the anterior margin of the retina with the anterior surface of the lens,
near its circumference. It assists in retaining the lens in its position. Its outer
surface presents a number of folds or plaitings, in which the corresponding folds
of the ciliary processes are received. These plaitings are arranged round the
lens in a radiating form, and are stained by the pigment of the ciliary processes.
The suspensory ligament consists of two layers, which commence behind, at the
ora serrata. The external, a tough, milky, granular membrane, covers the inner
surface of the ciliary processes,^ and extends as far forwards as their ante-
rior free extremities. The inner layer, an elastic transparent, fibro-membranous
structure, extends as far forwards as the anterior surface of the capsule of the
lens, near its circumference. That portion of this membrane which intervenes
between the ciliary processes and the capsule of the lens, forms part of the boun-
dary of the posterior chamber of the eye. The posterior surface of this layer is
turned towards the hyaloid membrane, being separated from it at the circum-
ference of the lens by a space called the canal of Petit.
The canal of Petit is about one-tenth of an inch wide. It is bounded in front
by the suspensory ligament; behind, by the hyaloid membrane, its base being
formed by the capsule of the lens. When inflated with aii', it is sacculated at
intervals, owing to the foldings on its anterior surface.
The vessels of the globe of the eye are the short, long, and anterior ciliary
arteries, and the arteria centralis retingg.
The Short Ciliary Arteries pierce the back part of the sclerotic, around the
entrance of the optic nerve, and divide into branches which run parallel with the
axis of the eyeball: they are distributed to the middle layer of the choroid, and
ciliary processes.
The Long Ciliary Arteries, two in number, pierce the back part of the
sclerotic, and run forward, between this membrane and the choroid, to the Ciliary
muscle, where they each divide into an upper and lower branch; these anastomose,
and form a vascular circle around the outer circumference of the iris: from this
circle branches are given off which unite, near the margin of the pupil, in a
002
564 ORG-ANS OF SENSE.
smaller vascular circle. These branches, in their course, supply the muscular
structure.
The Anterior Ciliary Arteries, five or six in number, are branches of the
muscular and lachrymal branches of the ophthalmic. They pierce the eyeball, at
the anterior part of the sclerotic, immediately behind the margin of the cornea,
and are distributed to the ciliary processes, some branches joining the greater
vascular circle of the iris.
The Arteria Centralis Retina has been already described.
The Veins, usually four in number, are formed mainly by branches from the
surface of the choroid. They perforate the sclerotic, midway between the cornea
and the optic nerve, and end in the ophthalmic vein.
The Nerves of the Eyeball, are the optic, the long ciliary nerves from the nasal
branch of the ophthalmic, and the short ciliary nerves from the ciliary ganglion.
Appendages op the Eye.
The appendages of the eye {tutamina oculi), include the eyebrows, the eyelids,
the conjunctiva, and the lachrymal apparatus, viz., the lachrymal gland, the
lachrymal sac, and the nasal duct.
The Eyebrows (stcpercilia) are two arched eminences of integument, which
surmount the upper circumference of the orbit on each side, and support numerous
short, thick hairs, directed obliquely on the surface. In structure, they consist of
thickened integument, connected beneath with the Orbicularis palpebrarum, Cor-
rugator supercilii, and Occipito-frontalis muscles. These muscles serve, by their
action on this part, to control to a certain extent the amount of light admitted
into the eye.
The Eyelids (palpebrte) are two thin, moveable folds, placed in front of the
eye, protecting it from injury by their closure. The upper lid is the larger,
the more moveable of the two, and supplied by a separate elevator muscle, the
Levator palpebrcB superioris. When the eyelids are opened, an elliptical space
{fissura palpebraruni), is left between their margins, the angles of which corre-
spond to the junction of the upper and lower lids, and are called canthi.
The outer canthus is more acute than the inner, and the lids here lie in close
contact with the globe: but the inner canthus is prolonged for a short distance
inwards, towards the nose, and the two lids are separated by a triangular space,
the lacus lachrymalis. At the commencement of the lacus lachrymalis, on the
margin of each eyelid, is a small conical elevation, the lachrymal papilla, or
tubercle, the apex of which is pierced by a small orifice, the punctum lachrymale,
the commencement of the lachrymal canal.
Structure of the Eyelids. The eyelids are composed of the following structures,
taken in their order from without inwards:
Integument, areolar tissue, fibres of the Orbicularis muscle, tarsal cartilage,
fibrous membrane. Meibomian glands, and conjunctiva. The upper lid has, in
addition, the aponeurosis of the Levator palpebrse.
The Integument is extremely thin, and continuous at the margin of the lids
with the conjunctiva.
The Subcutaneous Areolar Tissue is very lax and delicate, seldom contains
any fat, and is extremely liable to serous infiltration.
The Fibres of the Orbicularis Muscle, where they cover the palpebraa, are
thin, pale in colour, and possess an involuntary action.
The Tarsal Cartilages are two thin, elongated plates of fibro-cartilage, about
an inch in length. They are placed one in each lid, contributing to their form
and support.
The superior, the larger, is of a semilunar form, about one-third of an inch in
breadth at the centre, and becoming gradually nai-rowed at each extremity. Into
the fore part of this cartilage the aponeurosis of the Levator palpebras is attached.
The inferior tarsal cartilage, the smaller, is thinner, and of an elliptical form.
APPENDAGES OF THE EYE.
5^1
The free, or ciliary margin of the cartilages is t]iicl<, and presents a perfectly-
straight edge. The attached, or orbital margin, is connected to the circum-
ference of the orbit by the fibrous membrane of the lids. The outer angle of each
cartilage is attached to the malar bone, by the external palpebral or tarsal liga-
ment. The inner angles of the two cartilages terminate at the commencement
of the lacus lachrymalis, being fixed to the margins of the orbit })y the tendo
oculi.
The Fibrous Membrane of the Lids, or tarsal ligament, is a layer of fibrous
membrane, beneath the Orbicularis, attached, externally, to the margin of the
orbit, and internally to the orbital margin of the lids. It is thick and dense at
the outer part of the orbit, but becomes thinner as it approaches the cartilages.
This membrane serves to support the eyelids, and retains the tarsal cartilages in
their position.
The Meibomian Glands (fig. 286) are situated upon the inner surface of the
eyelids, between the tarsal cartilages and conjunctiva, and may be distinctly seen
through the mucous membrane on everting the eyelids, presenting the appearance
of parallel strings of pearls. They are about thirty in number in the upper carti-
lage, and somewhat fewer in the lower. They are imbedded in grooves in the
inner surface of the cartilages, and correspond in length with the breadth of each
286.— The Meibomian Glands, etc., seen from the Inner Surface
of the Eyelids.
cartilage; they are, consequently, longer in the upper than in the lower eyelid.
Their ducts open on the free margin of the lids by minute foramina, which
correspond in number to the follicles. These glands are a variety of the
cutaneous sebaceous glands, each consisting of a single straight tube or follicle,
having a coecal termination, into which open a number of small secondary follicles.
The tubes consist of a basement membrane, covered by a layer of scaly epithelium;
the cells are charged with sebaceous matter, which constitutes the secretion.
The peculiar parallel arrangement of these glands side by side, forms a smooth
layer, admirably adapted to the surface of the globe, over which they constantly
glide. The use of their secretion is to prevent adhesion of the lids.
The Eyelashes {Cilia) are attached to the free edges of the eyelids; they are
short, thick, curved hairs, arranged in a double or triple row at the margin of the
lids: those of the upper lid, more numerous and longer than the lower, curve
upwards; those of the lower lid curve doAvnwards, by which means they do not
interlace in closiner the lids.
566 OKGANS OF SENSE.
The Conjunctiva is the mucous membrane of the eye. It lines the inner sur-
face of the eyelids, and is reflected over the fore part of the sclerotic and cornea.
In each of these situations, its structure presents some peculiarities.
The palpebral portion of the conjunctiva is thick, opaque, highly vascular, and
covered with numerous papillte, which, in the disease called granular lids, become
greatly hypertrophied. At the margin of the lids, it becomes continuous with the
lining membrane of the ducts of the Meibomian glands, and, through the lachrymal
canals, with the lining membrane of the lachrymal sac and nasal duct. At the
outer angle of the upper lid, it may be traced along the lachrymal ducts into
the lachrymal gland; and at the inner angle of the eye, it forms a semilunar
fold, the plica semilunaris. The folds formed by the reflection of the con-
junctiva from the lids on to the eye are called the superior and inferior palpebral
folds, the former being the deeper of the two. Upon the sclerotic, the conjunctiva
is loosely connected to the globe; it becomes thinner, loses its papillary structure,
is transparent, and only slightly vascular in health. Upon the cornea, the con-
junctiva is extremely thin and closely adherent, and no vessels can be traced into
it in the adult in a healthy state. In the foetus, fine capillary loops extend, for
some little distance forwards, into this membrane; but in the adult, they pass only
to the circumference of the cornea.
The Caruncula Lachrymalis is a small, reddish, conical-shaped body, situated
at the inner canthus of the eye, and filling up the small triangular space in this
situation, the lacus lachrymalis. It consists of a cluster of follicles similar in
structure to the Meibomian, covered with mucous membrane, and is the source of
the whitish secretion which constantly collects at the inner angle of the eye. A
few slender hairs are attached to its surface. On the outer side of the caruncula
is a slight semilunar fold of mucous membrane, the concavity of which is directed
towards the cornea; it is called the plica semilunaris. Between its two layers is
found a thin plate of cartilage. This structure is considered to be the rudiment
of the third eyelid in birds, the membrana nictitans.
Lachrymal Apparatus (fig. 287).
The lachrymal apparatus consists of the lachrymal gland, which secretes the
287. — The Lachrymal Apparatus. Right Side.
tears, and its excretory ducts, which convey the fluid to the surface of the eye.
This fluid is carried away by the lachrymal canals into the lachrymal sac, and
along the nasal duct into the cavity of the nose.
LACHRYMAL APPARATUS. 567
The Lachrymal Gland is lodged in a depression at the outer angle of the
orbit, on the inner side of the external angular process of the frontal bone. It is
of an oval form, about the size and shape of an almond. Its upper convex surface
is in contact with the periosteum of the orbit, to which it is connected by a few
fibrous bands. Its under concave surftice rests upon the convexity of the eyeball,
and upon the Superior and External recti muscles. Its vessels and nerves enter
its posterior border, whilst its anterior margin is closely adherent to the back part
of the upper eyelid, and is covered, on its inner surface, by a reflection of the
conjunctiva. This margin is separated from the rest of tlae gland by a slight
depression, and is hence sometimes described as a sepai-ate lobe, called the palpe-
bral portion of the gland. In structure and general appearance, it resembles the
salivary glands. Its ducts, about seven in number, run obliquely beneath the
mucous membrane for a short distance, and sei^arating from each other, open by a
series of minute orifices on the upper and outer half of the conjunctiva, near its
reflexion on to the globe. These orifices are arranged in a row, so as to disperse
the secretion over the surface of the membrane.
The Lachrymal Canals commence at the minute orifices, puncta lachrymalia,
seen on the margin of the lids, at the outer extremity of the lacus lachrymalis.
They commence on the summit of a slightly elevated papilla, the papilla lachry-
malis, and lead into minute canals, the canaliculi, which proceed inwards to
terminate in the lachrymal sac. The superior canal, the siiialler and longer of
the two, at first ascends, and then bends at an acute angle, and passes inwards
and downwards to the lachrymal sac. The inferior canal at first descends, and
then abruptly changing its course, passes almost horizontally inwards. They
are dense and elastic in structure, and somewhat dilated at their angle.
The Lachrymal Sac is the upper dilated extremity of the nasal duct, and is
lodged in a deep groove formed by the lachrymal and nasal process of the supe-
rior maxillary bone. It is oval in form, its upper extremity being closed in and
rounded, whilst below it is continued into the nasal duct. It is covered by a
fibrous expansion derived from the tendo oculi, which is attached to the ridge on
the lachrymal bone, and also by the Tensor tarsi muscle. In structure, it consists
of a fibrous elastic coat, lined internally by mucous membrane, which is continuous,
through the canaliculi, with the mucous lining of the conjunctiva, and through the
nasal duct with the pituitary membrane of the nose.
The Nasal Duct is a membranous canal, about three quarters of an inch in
length, which extends from the lower part of the lachrymal sac to the inferior
meatus of the nose, where it terminates by a somewhat expanded orifice, provided
with an imperfect valve formed by the mucous membrane. It is contained in an
osseous canal, formed by the superior maxillary, the lachrymal, and the inferior
turbinated bones, is narrower in the middle than at each extremity, and takes a
direction downwards, backwards, and a little outwards. It is lined by mucous
membrane, which is continuous below with the pituitary lining of the nose. In
the canaliculi, this membrane is provided with scaly epithelium, but in the lach-
rymal sac and nasal duct it is ciliated as in the nose.
The Eae.
The organ of hearing consists of three parts; the external ear, the middle ear
or tympanum, and the internal ear or labyrinth.
The External Ear consists of an expanded portion or pinna, and the auditory
canal or meatus. The former serves to collect the vibrations of the air consti-
tuting sound, and the latter conducts those vibrations to the tympanum.
The Pinna, or Auricle (fig. 288), consists of a layer of cartilage, covered by
integument, and connected to the commencement of the auditory canal; it is of an
ovoid foi-m, its surface uneven, with its larger end directed upwards. Its outer
surface is irregularly concave, directed slightly forwards, and presents numerous
568
ORGANS OF SENSE.
288. — The Pinna or Auricle.
Outer Surface.
eminences and depressions, which result from the foldings of its fibro-cartilaginous
element. To each of these, names have been assigned. Thus, the external pro-
minent rim of the auricle is called the helix.
Another curved prominence parallel with, and
in front of the helix, is called the antihelix ;
this bifurcates above into two parts, so as to
enclose a triangular depression, the fossa of
the antihelix. The narrow curved depression
between the helix and antihelix, is called the
fossa of the helix {Jossa innominata, scaphoi-
dea). The antihelix describes a circuit around
a deep, capacious cavity, the concha, which is
partially divided into two parts by the com-
mencement of tfie helix. In front of the
concha, and projecting backwards over the
meatus, is a small pointed eminence, the tra-
gus ; so called from its being generally covered,
on its under surface, with a tuft of hairs, re-
sembling a goat's beard. Opposite the tragus,
and separated from it by a deep notch {inci-
sura intertragica), is a small tubercle, the anti-
tragus. Below this is the lobule, composed
of tough areolar and adipose tissues, want-
ing the firmness and elasticity of the rest of
the pinna.
Structure of the Pinna. The pinna is composed of a thin plate of cartilage,
covered with integument, and connected to the surrounding parts by ligaments,
and a few muscular fibres.
The Integument is thin, closely adherent to the cartilage, and furnished with
sebaceous glands, which are most numerous in the concha and scaphoid fossa.
The Cartilage of the Pinna consists of one single piece; it gives form to this
part of the ear, and upon its surface are found all the eminences and depressions
above described. It does not enter into the construction of all parts of the aui'i-
cle, and presents several intervals or fissures in its substance, which partially
separate the different parts. Thus, it does not form a constituent part of the
lobule; it is deficient, also, between the tragus and beginning of the helix, the
notch between them being filled up by dense fibrous tissue. The fissures in the
cartilage are the fissure of the helix, a short, vertical slit, situated at the fore
part of the pinna, immediately behind a small conical projection of cartilage,
opposite the first curve of the helix (process of the helix); another fissure, the
fissure of the tragus, is seen upon the anterior surface of the tragus. The anti-
helix is divided below, by a deep fissure, into two parts; one part terminates by
a pointed, tail-like extremity {processus caudatus); the other is continuous with
the anti tragus. The cartilage of the pinna is very pliable, elastic, of a yellow-
ish colour, and is similar in structure to the cartilages of the alee nasi.
The Ligaments of the Piniia consist of two sets. I. Those connecting it to
the side of the head. 2. Those connecting the various parts of its cartilage
together.
The former, the most important, are two in number, anterior and posterior.
The anterior ligament extends from the process of the helix, to the root of the
zygoma. The posterior ligament passes from the posterior surface of the concha,
to the outer surface of the mastoid process of the temporal bone. A few fibres
connect the tragus to the root of the zygoma.
Those connecting the various parts of the cartilage together, are also two in
number. Of these, one is a strong fibrous band, stretching across from the tragus
to the commencement of the helix, completing the meatus in front, and partly
MUSCLES OF THE PINNA.
569
encircling the boundary of the concha; the other extends between the concha and
the processus caudatus.
The Muscles of the Pinna (fig. 289), lilce the ligaments, also consist of two
sets. I. Those which connect it with the side of the head, moving the pinna as
289. — The Muscles of the Pinna.
a whole, viz. the Attollens, Attrahens and Retrahens aurem, already described;
and the proper muscles of the pinna, which extend from one part of the auricle
to another. These are the
Helicis major.
Helicis minor.
Trasricus.
Antitragicus.
Transversus auriculee.
Obliquus auris.
The Helicis major is a narrow, vertical band of muscular fibres, situated upon
the anterior margin of the helix. It arises, below, from the tubercle of the helix,
and is inserted into the anterior border of the helix, just where it is about to
curve backwards. It is pretty constant in its existence.
The Helicis minor is an oblique fasciculus, firmly attached to that part of the
helix which commences from the bottom of the concha.
The Tragicus is a short, flattened band of muscular fibres, situated upon the
outer surface of the tragus; the direction of its fibres being vertical.
The Antitragicus arises from the outer part of the an ti tragus; its fibres are
inserted into the processus caudatus of the helix. This muscle is usually very
distinct.
The Transversus auriculce is placed on the cranial surface of the pinna. It
consists of radiating fibres, partly tendinous and partly muscular, extending from
the convexity of the concha, to the prominence corresponding with the groove of
the helix.
570
ORGANS OF SENSE.
The Ohliquus auris (Tod) consists of a few fibres extending from the upper
and back part of the concha, to the convexity immediately above it.
The Arteries of the Pinna are the posterior auricular, from the external caro-
tid; the anterior auricular, from the temporal; and an auricular branch from the
occipital artery.
The Veins accompany the corresponding arteries.
The Nerves are the auricularis magnus, from the cervical plexus; the posterior
auricular, from the facial; the auricular branch of the pneumogastric ; and the
auriculo- temporal branch of the inferior maxillary nerve.
The Auditory Canal (fig. 290), {meatus auditorius externus), conveys the
vibrations of the air to the tympanum, and extends from the bottom of the concha
— A Front View of the Organ of Hearing. Eight Side.
to the membrana tympani. It is about an inch and a quarter in length, its direc-
tion obliquely forwards and inwards, and it is slightly curved upon itself, so as to
be higher in the middle than at either extremity. It forms an oval cylindrical
canal, somewhat flattened from before backwards, the greatest diameter being in
the vertical direction at the external orifice; but, in the transverse direction, at
the tympanic end. The membrana tympani, which occupies the termination of
the meatus, is obliquely directed, in consequence of the floor of this canal being
longer than the roof, and the anterior wall longer than the posterior. The audi-
tory canal is formed pai-tly by cartilage and fibrous tissue, and partly by bone.
The cartilaginous portion is about half an inch in length, being rather less
than half the canal; it is formed by the cartilage of the concha and tragus being
prolonged inwards to the circumference of the auditory process, to which it is
firmly attached. This tube is deficient at the upper and back part, its place
being supplied by fibrous membrane. This part of the canal is rendered
extremely moveable, by two or three deep fissures {incisures Santorini) which
extend through the cartilage in a vertical direction.
The osseous portion of the meatus is about three-quarters of an inch in length,
and is longer and narrower than the cartilaginous portion. It is directed inwards
and a little forwards, forming a slight curve in its course, the convexity of which
is upwards and backwards, and it terminates in the external orifice of the tympa-
num. Its inner end is smaller than the outer, and it is slightly contracted in the
middle. Its vertical transverse section is oval, the greatest diameter being from
above downwards. The front and lower parts of this canal are formed by a
THE TYMPANUM.
571
curved plate of bone, presenting a rough margin externally, to which the cartilage
of the pinna is attached. This osseous plate, in the foetus, exists as a separate
ring of bone (tympanic bone), incomplete at its upper part.
The skin lining the meatus is very thin, closely adherent to the cartilaginous
and osseous portions of the tube, and covers the surface of the membrana tympani,
forming its outer layer. After maceration, the thin pouch of epidermis, when
withdrawn, preserves the form of the meatus. The skin near the orifice is sup-
plied with hairs, sebaceous glands, and numerous ceruminous glands, which
furnish an abundant secretion, calculated to prevent the ingress of insects and
particles of dust.
The Arteries supplying the meatus are branches from the posterior auricular,
internal maxillary, and temporal.
The Nerves are chiefly derived from the temporo-auricular branch of the infe-
rior maxillary nerve.
Middle Ear, or Tympanum.
The middle ear, or tympanum, is an irregular cavity, compressed from without
inwards, and situated within the petrous bone. It is placed above the jugular
fossa, the carotid canal lying in front, the mastoid cells behind, the meatus audito-
rius externally, and the labyrinth within. It is filled with air, and communicates
with the pharynx by the Eustachian tube. The tympanum is traversed by a
chain of moveable bones, which connect the membrana tympani with the laby-
rinth, and serve to convey the vibrations communicated to the membrana tympani
across the cavity of the tympanum to the internal ear.
The Cavity of the Tympanum measures about five lines from before backwards,
three lines in the vertical direction, and between two and three in the transverse,
being a little broader behind and above than below and in front. It is bounded
externally by the membrana tympani and meatus: internally, by the outer surface
of the internal ear; behind, by the mastoid cells; and, in front, by the Eustachian
tube and canal for the Tensor tympani. Its roof and floor are formed by thin
osseous lamellae, which connect the squamous and petrous portions of the tem-
poral bone.
The roof is broad, flattened, and formed of a thin plate of bone, which
separates the cranial and tympanic cavities.
The^oor is narrow, and corresponds to the jugular fossa, which lies beneath.
The outer wall is formed by the membrana tympani, a small portion of bone
being seen above and below this membrane. It presents three small apertures,
the iter chordae posterius, the Glasserian fissure, and the iter chordae anterius.
The Aperture of the Iter ChordcB Posterius is behind the aperture for the mem-
brana tympani, close to its margin, at a level with its centre; it leads into a minute
canal, which descends in front of the aqueductus Fallopii, and terminates in this
canal near the stylo-mastoid foramen. It transmits the chorda tympani nerve.
The Glasserian Fissure opens just above and in front of the orifice of the mem-
brana tympani; in this situation it is a mere slit, about a line in length. It gives
passage to the long process of the malleus, the Laxator tympani muscle, and some
tympanic vessels.
The Aperture of the Iter Chordae Anterius is seen just above the preceding
fissure; it leads into a canal which runs parallel with the Glasserian fissure, and
transmits the chorda tympani nerve.
The internal wall of the tympanum is vertical in direction, and looks directly
outwards. It presents for examination the following parts:
Fenestra ovalis. Ridge of the Aqueductus Fallopii.
Fenestra rotunda. Pyramid.
Promontory. Opening for the Stapedius.
The Fenestra Ovalis is a reniform opening, leading from the tympanum into
S72
ORaANS OF SENSE.
the vestibule; its long diameter is directed horizontally, and its convex border is
upwards. The opening in the recent state is closed by the lining membrane
common to both cavities, and is occupied by the base of the stapes. This mem-
brane is placed opposite the membrana tympani, and is connected with it by the
ossicula auditus.
The Fenestra Rotunda is an oval aperture, placed at the bottom of a funnel-
291. — View of Inner Wall of Tympanum (Enlarged).
Chorda Tymp^
shaped depression, leading into the cochlea. It is placed below and rather behind
the fenestra ovalis, from which it is separated by a rounded elevation, the pro-
montory; it is closed in the recent state by a membrane {niembrana tympani
secundaria, Scarpa). This memlirane is concave towards the tympanum, convex
towards the cochlea. It consists of three layers: the external, or mucous, is
derived from the mucous lining of the tympanum; the internal, or serous, from
the lining membrane of the cochlea; and an intermediate, or fibrous layer.
The Promontory is a rounded hollow prominence, formed by the projection
outwards of the first turn of the cochlea; it is placed between the fenestras, and
furrowed on its surface by three small grooves, which lodge branches of the
tympanic plexus.
The Rounded Eminence of the Aqueductus Fallopii is placed between the
fenestra ovalis and roof of the tympanum; it is the prominence of the bony canal
in which the portio dura is contained. It traverses the inner wall of the tym-
panum above the fenestra ovalis, and behind that opening, curves nearly vertically
downwards along the posterior wall.
The Pyramid is a conical eminence, situated immediately behind the fenestra
ovalis, and in front of the vertical portion of the eminence above described; it is
hollow in the interior, and contains the Stapedius muscle; its summit projects
forwards towards the vestibular fenestra, and presents a small aperture, which
transmits the tendon of this muscle. The cavity in the pyramid is prolonged into
a canal, which descends vertically, parallel with the aqueductus Fallopii, and ter-
minates at the base of the petrous portion of the temporal bone, in front and to
the inner side of the stylo-mastoid foramen. This canal communicates with the
aqueductus Fallopii.
The posterior wall of the tympanum, is wider above than below, and presents
for examination the
Openings of the Mastoid Cells.
They consist of one large irregular aperture, and several smaller openings.
THE TYMPANUM.
573
situated at the upper part of the posterior wall; they lead into canals, which com-
municate with large irregular cavities contained in the interior of the mastoid
process. These cavities vary considerably in number, size, and form; they are
lined by mucous membrane, continuous with that covering the cavity of the
tympanum.
The anterior wall of the tympanum is wider al)ove than l)elow; it corre-
sponds with the carotid canal, from which it is separated by a thin plate of bone;
it presents for examination the
Canal for the Tensor tympani. Orifice of the Eustachian Tube.
The Processus Cochleariformis.
The orifice of the canal for the tensor Tympani, and the orifice of the Eustachian
tube, are situated at the upper part of the anterior wall, being separated from
each other by a thin, delicate, horizontal plate of bone, the processus cochleari-
formis. These canals run from the tympanum forward, inward, and a little
downward, to the retiring angle between the squamous and petrous portions of the
temporal bone.
The canal for the tensor Tympani is the superior and the smaller of the two;
it is rounded, and lies beneath the upper surface of the petrous bone, close to the
hiatus Fallopii. The tympanic end of this canal forms a conical eminence, which
is prolonged backwards into the cavity of the tympanum, and is perforated at its
summit by an aperture, which transmits the tendon of the muscle contained in it.
This eminence is sometimes called the anterior pyramid. The canal contains the
Tensor tympani muscle.
The Eustachian tube is the channel through which the tympanum communi-
cates with the pharynx. Its length is from an inch and a half to two inches, and
its direction downwards, forwards, and inwards. It is formed partly of bone,
partly of cartilage and fibrous tissue.
The osseous portion is about half an inch in length. It commences in the lower
part of the anterior wall of the tympanum, below the processus cochleariformis,
and gradually narrowing, terminates in an oval dilated opening, at the angle of
junction of the petrous and squamous portions, its extremity presenting a jagged
margin, which serves for the attachment of the cartilaginous portion.
The cartilaginous portion, about an inch in length, is formed of a triangular
plate of cartilage, curled upon itself, an interval being left below, between the
non-approximated margins of the cartilage, which is completed by fibrous tissue.
Its canal is narrow behind, wide, expanded, and somewhat trumpet-shaped in,
front, terminating by an oval orifice, placed at the upper part and side of
the pharynx, behind the back part of the inferior meatus. Through this canal
the mucous membrane of the pharynx is continuous with that which lines the
tympanum.
The Membrana Tympani separates the cavity of the tympanum from the
bottom of the external meatus. It is a thin semitransparent membrane, nearly oval
in form, somewhat broader above than below, and directed very obliquely down-
wards and inwards. Its circumference is contained in a groove at the inner end
of the meatus, which skirts the circumference of this part excepting above. The
handle of the malleus descends vertically between the inner and middle layers of
this membrane as far down as its centre, where it is firmly attached, drawing the
membrane inwards, so that its outer surface is concave, its inner convex.
Structure. This membrane is composed of three layers, an external (cuticular),
a middle (fibrous), and an internal (mucous). The cuticular lining is derived from
the integument lining the meatus. The fibrous layer consists of fibrous and
elastic tissues; some of the fibres radiate from near the centre to the circum-
ference; others are arranged, in the form of a dense circular ring, around the
attached margin of the membrane. The mucous lining is derived from the mucous
lining of the tympanum. The vessels pass to the membrana tympani along the
handle of the malleus, and are distributed between its layers.
74 ORGANS OF SENSE.
Ossicles of the Tympanum.
The tympanum is traversed by a chain of moveable bones, three in number, the
malleus, incus, and stapes. The former is attached to the membrana tympani, the
latter to the fenestra ovalis, the incus being placed between the two, to both of
which it is connected by delicate articulations.
The Malleus, so named from its fancied resemblance to a hammer, consists of a
head, neck, handle or manubrium, and two processes, viz., the processus gracilis
and the processus brevis.
The head is the large upper extremity of the bone; it is oval in shape, and
articulates posteriorly with the incus, being free in the rest of its extent.
The neck is the narrow contracted part just beneath the head; and below this is
a prominence, to which the various processes are attached.
The manubrium is a vertical portion of bone, which is connected by its outer
margin with the membrana tympani. It decreases in size towards its extremity,
where it is curved slightly forwards, and flattened from within outwards.
The processus gracilis is a long and very delicate process, which passes from
the eminence below the neck forwards and outwards to the Glasserian fissure, to
which it is connected by bone and ligamentous fibres. It gives attachment to the
Laxator tympani.
The processus brevis is a slight conical projection, which springs from the root
of the manubrium, and lies in contact with the membrana tympani. Its summit
gives attachment to the Tensor tympani.
The Incus has received its name from its resemblance to an anvil, but it does
not look unlike a bicuspid tooth, with two
292.— The Small Bones of the Ear, seen roots, which differ in length, and are widely
from the Outside (Enlarged). separated fiK)m each other. It consists of a
body and two processes.
The body is somewhat quadrilateral, but
compressed laterally. Its summit is deeply
concave, and ai'ticulates with the malleus; in
the fresh state, it is covered with cartilage
and lined with synovial membrane.
The two processes diverge from one an-
other nearly at right angles.
The short process, somewhat conical in
shape, projects nearly horizontally back-
wards, and is attached to the margin of the
opening leading into the mastoid cells by
ligamentous fibres.
The long process, longer and more slender than the preceding, descends nearly
- vertically behind the handle of the malleus, and bending inwards, terminates in a
rounded globular projection, the os orbicular e, tipped with cartilage, and articu-
lating with the head of the stapes. In the foetus the os orbiculare exists as a
separate bone, but becomes united to the long process of the incus in the adult.
The Stapes, so called from its close resemblance to a stirrup, consists of a head,
neck, two branches, and a base.
The head presents a depression, tipped with cartilage, which articulates with
the OS orbiculare.
The neck, the constricted part of the bone below the head, receives the insertion
of the Staj)edius muscle.
The two branches {crura), diverge from the neck, and are connected at their
extremities by a flattened, oval- shaped plate (the base), which forms the foot of
the stirrup, and is fixed to the margin of the fenestra ovalis by ligamentous
fibres.
Ligaments of the Ossicula. These small bones are connected with each other,
and with the tympanum, by ligaments, and moved by small muscles. The articular
MUSCLES OF THE TYMPANUM. 575
surfaces of the malleus and incus, the orbiculai* process of the incus and head
of the stapes, are covered with cartilage, connected together by delicate capsular
ligaments, and lined by synovial membrane. The ligaments connecting the ossi-
cula with the walls of the tympanum, are three in number, one for each bone.
The Suspensory Ligament of the 3Ialleus is a delicate, round bundle of fibres,
which descends perpendicularly from the roof of the tympanum to the head of the
malleus.
The Posterior Ligament of the Lncus is a short, thick ligamentous band, which
connects the extremity of the short process of the incus to the posterior wall of
the tympanum, near the margin of the opening of the mastoid cells.
The Annular Ligament of the Stapes connects the circumference of the base
of this bone to the margin of the fenestra ovalis.
A Suspensory Ligament of the Incus has been described by Arnold, descend-
ing from the roof of the tympanum to the upper part of the incus, near its
articulation with the malleus.
The muscles of the tympanum are three:
Tensor tympani. Laxator tympani. Stapedius.
The Tensor Tympani, the largest, is contained in a bony canal, above the
osseous portion of the Eustachian tube, from which it is separated by the pro-
cessus cochleariformis. It arises from the under surface of the petrous bone,
from the cartilaginous portion of the Eustachian tube, and from the osseous canal
in which it is contained. Passing backwards, it terminates in a slender tendon,
which is reflected outwards over the processus cochleariformis, and is inserted
into the handle of the malleus, near its root. It is supplied by a branch from
the otic ganglion.
The Laxator Tympani major (Soemmering), arises from the spinous process
of the sphenoid bone, and from the cartilaginous portion of the Eustachian tube;
passing backwards through the Glasserian fissure, it is inserted into the neck of
the malleus, just above the processus gracilis. It is supplied by a branch from
the chorda tympani.
^ The Laxator Tympani minor (Soemmering), arises from the upper and back
part of the external meatus, passing forwards and inwards between the middle
and inner layers of the membrana tympani; it is inserted into the handle of the
malleus, and processus brevis. This is considered as a ligament by some
anatomists.
The Stapedius is lodged in a cavity hollowed out of the interior of the pyramid.
It arises from the sides of this conical cavity: its tendon emerges from the orifice
at its apex, and, passing forwards, is inserted into the neck of the stapes. Its
surface is aponeurotic, its interior fleshy, and its tendon occasionally contains a
slender bony spine, which is constant in some mammalia. It is supplied by a
filament from the facial nerve.
Actions. The Tensor tympani draws the membrana tympani inwards, and thus
heightens its tension. The Laxator tympani draws the malleus outwards, and
■thus the tympanic membrane, especially at its fore part, is relaxed. The Stape-
dius depresses the back part of the base of the stapes, and raises its fore part. It
probably compresses the contents of the vestibule.
The Mucous Membrane of the Tympanum is thin, vascular, and continuous
with the mucous membrane of the pharynx, through the Eustachian tube. It
.invests the ossicula, and the muscles and nerves contained in the tympanic
cavity; forms the internal layer of the membrana tympani; covers the foramen
rotundum; and is reflected into the mastoid cells, which it lines throughout. In
the tympanum and mastoid cells, this membrane is pale, thin, slightly vascular,
and covered with ciliated epithelium. In the osseous portion of the Eustachian
tube, the membrane is thin; but, in the cartilaginous poi'tion, it is very thick,
highly vascular, covered with ciliated laminar epithelium, and provided with
numerous mucous elands.
576 ORGANS OF SENSE.
The Arteries supplying the Tympanum are five in number, viz., the tympanic
branch of the internal maxillary, which supplies the membrana tympani; the
stylo-mastoid branch of the posterior auricular, which supplies the back part of
the tympanum and mastoid cells. The smaller branches are, the petrosal branch
of the middle meningeal, and branches from the ascending pharyngeal and
internal carotid.
The Veins of the Tympanum terminate in the middle meningeal and pharyngeal
veins, and, through these, in the internal jugular.
The Nerves of the Tympanum may be divided into: I, Those supplying the
muscles; 2, Those distributed to the lining membrane; 3, Branches communicat-
ing with other nerves.
Nerves to Muscles. The Tensor tympani is supplied by a branch from the otic
ganglion; the Laxator tympani, by the chorda tympani; and the Stapedius, by a
filament from the facial (Soemmering).
The Nerves distributed to the Lining Membrane are derived from the tympanic
plexus.
Communications between the following nerves take place in the tympanum: the
Tympanic branch, from the petrous ganglion of the glosso-pharyngeal ; a filament
from the carotid plexus; a branch which joins the great superficial petrosal nerve
from the Vidian; and a branch to the otic ganglion (small superficial petrosal
nerve).
The Tympanic Branch of the Glosso-Pharyngeal (Jacobson's nerve), enters
the tympanum by an aperture in its floor, close to the inner wall, and ascends on
to the promontory. It distributes filaments to the lining membrane of the tympa-
num, and divides into three branches, which are contained in grooves on the
promontory, and serve to connect this with other nerves. One branch runs in a
groove, forwards and downwards, to an aperture' situated at the junction of the
anterior and inner walls, just above the floor, and enters the carotid canal, to
communicate with the carotid plexus of the sympathetic. The second branch is
contained in a groove which runs vertically upwards to an aperture on the inner
wall of the tympanum, just beneath the anterior pyramid, and in front of the
fenestra ovalis. The canal leading from this opens into the hiatus Fallopii,
where it joins the great petrosal nerve. The third branch ascends towards the
anterior surface of the petrous bone; it then passes through a small aperture in
the sphenoid and temporal bones to the exterior of the skull, and joins the otic
ganglion. As this nerve passes by the gangliform enlargement of the facial, it
has a connecting filament with it.
The Chorda Tympani quits the facial near the stylo-mastoid foramen, enters
the tympanum at the base of the pyramid, and arches forwards across its cavity,
between the handle of the malleus and long process of the incus, to an opening
internal to the fissura Glasseri. It is invested by a reflection of the lining mem-
brane of the tympanum.
Internal Ear, or Labyrinth.
The internal ear is the essential part of the acoustic organ, receiving the
ultimate distribution of the auditory nerve. It is called the labyrinth, from the
complexity of its communications, and consists of three parts, the vestibule, semi-
circular canals, and cochlea. It consists of a ■ series of cavities, channelled out of
the substance of the petrous bone, communicating externally with the cavity of
the tympanum, through the fenestra ovalis and rotunda; and internally, with the
meatus auditorius internus, which contains the auditory nerve. Within the
osseous labyrinth, is contained the membranous labyrinth, upon which the ramifi-
cations of the auditory nerve are distributed.
The Vestibule is the common central cavity of communication between the
parts of the internal ear. It is situated on the inner side of the tympanum,
behind the cochlea, and in front of the semicircular canals. It is somewhat
ovoidal in shape from before backwards, flattened from side to side, and measures
VESTIBULE; SEMICIRCULAR CANALS. 577
about one-fifth of an inch from before backwards, as well as from above down-
wards, being narrower from without inwards. On its outer, or tympanic
wall, is the fenestra ovalis, closed, in the recent state, by the base of the
stapes, and its annular ligament. On its inner tvall, at its fore part, is a
293.— The Osseous Labyrinth, laid open. (Enlarged).
Ope-rttit^ of
small circular depression, fovea hemispherica ; it is perforated at its ante-
rior and inferior part by several minute holes {macula cribrosa^, for the pas-
sage of filaments of the auditory nerve; and behind it is a vertical ridge, the
pyramidal eminence. At the back part of the inner wall is the orifice of the
aqueductus vestibuli, which extends to the posterior surface of the petrous
portion of the temporal bone. It transmits a small vein, and, according to some,
contains a tubular prolongation of the lining membrane of the vestibule^ which
ends in a cul-de-sac, between the layers of the dura mater within the cranial
cavity. On the upper wall, or roof, is a transversely-oval depression, fovea
semi-elliptica, separated from the fovea hemispherica by the pyramidal eminence,
already mentioned. Behind, the semicircular canals open into the vestibule by
five orifices. In front, is a larger oval opening which communicates with the
scala vestibuli of the cochlea by a single orifice, apertura scalce vestibuli
cochlecB.
The Semicircular Canals are three bony canals, situated above and behind the
vestibule. They are of unequal length, compressed from side to side, and describe
the greater part of a circle. They measure about one-twentieth of an inch in
diameter, and each presents a dilatation at one end, called the ampulla, which
measures more than twice the diameter of the tube. These canals open into the
vestibule by five orifices, one of the apertures being common to two of the
canals.
The superior semicircular canal is vertical in direction, its arch forming a
round projection on the anterior surface of the petrous bone. It forms about two-
thirds of a circle. Its outer extremity, which is ampullated, commences by a
distinct orifice in the upper part of the vestibule; the opposite end of the canal,
which is not dilated, joins with the corresponding part of the posterior canal, arid
opens by a common orifice with it in the back part -of the vestibule.
The posterior semicircular canal, also vertical in direction, is directed liack-
p p
578
ORGANS OF SENSE.
wards to the posterioi* surface of the petrous bone: it is the longest of the three,
its ampullated end commencing at the lower and back part of the vestibule, its
opposite end joining the common canal already mentioned.
The external, or horizontal canal, is the shortest of the three, its arch being
dii'ected outwards and backwards. Its ampullated end corresponds to the upper
and outer angle of the vestibule, just above the fenestra ovalis; its opposite end
opens by a distinct orifice at the upper and back part of the vestibule.
The Cochlea bears some resemblance to a common snail-shell : it forms
the anterior part of the labyrinth, is conical in form, and placed almost hori-
zontally in front of the vestibule; its apex is directed forwards and outwards
towards the upper and front part of the inner wall of the tympanum; its base
corresponds with the anterior depression at the bottom of the internal auditory
meatus; and is perforated by numerous apertures,, for the passage of the coch-
lear branch of the auditory nerve. It measures about a quarter of an inch in
length, and its breadth towards the base is about the same. It consists of a
conical-shaped central axis, the modiolus or columella; of a canal wound spirally
round the axis for two turns and a half; and of a delicate lamina (the lamina
spiralis) contained within the canal, which follows its windings, and subdivides it
into two.
The central axis, or modiolus, is conical in form, and extends from the base
to the apex of the cochlea. Its base is broad, corresponds with the first turn of
the cochlea, and is perforated by numerous orifices, which transmit filaments
of the cochlear branch of the auditory nerve; the axis diminishes rapidly in size in
the second coil, and terminates within the last half coil, or cupola, in an expanded,
delicate, bony lamella, which resembles the half of a funnel, divided longitudinally,
and called the infundibulum ; the broad part of this funnel is directed towards
the summit of the cochlea, and blends with the last half-turn of the spiral canal
of the cochlea, the cupola. The outer surface of the modiolus is formed of the
wall of the spiral canal, and is dense in structure; but its centre is channelled, as
far as the last half-coil, by numerous branching canals, which transmit nervous
filaments in regular succession into the canal of the cochlea, or upon the surface
of the lamina spiralis. One of these, larger than the rest, occupies the centre
of the modiolus, and is named the tubulus centralis modioli; it extends from
the base to the extremity of the modiolus, and transmits a small nerve and artery
{arteria centralis modioli).
The spiral canal (fig. 294) takes two turns and a half round the modiolus.
It is about an inch and a half in length, measured along its outer wall; and dimi-
294. — The Cochlea laid open (enlarged).
nishes gradually in size from the base to the summit, where it terminates in a
cul-de-sac, the cupola, which forms the apex of the cochlea. The commencement
of this canal is about the tenth of an inch in diameter: it diverges from the modio-
lus towards the tympanum and vestibule, and presents three openings. One, the
COCHLEA, 579
fenestra rotunda, communicates with the tympanum : in the recent state, this
aperture is closed by a membrane, the memhrana tympani secundaria. Another
aperture, of an oval form, enters the vestibule. The third is the aperture of the
aqueductus cochlece, which leads to a minute funnel-shaped canal, which opens
on the basilar surface of the petrous bone, and transmits a small vein.
The interior of the spiral canal is divided into two passages {scalce) by a
thin, osseous, and membranous lamina, which winds spirally round the modiolus.
This is the lamina spiralis, the essential part of the cochlea upon which the
nerve tubules are distributed. The osseous part of the spiral lamina extends
about half way across the diameter of the spiral canal; it is called the osseous
zone. It commences in the vestibule between the tympanic and vestibular open-
ings of the cochlea, and, gradually becoming narrower in its course, terminates in
a projecting hook, the hamular process, just where the expansion of the infundi-
bulum commences. The lamina spiralis consists of two thin lamellse of bone,
between which are numerous canals for the passage of nervous filaments, which
open chiefly on the lower or tympanic surface. At the point where the osseous
lamina is attached to the modiolus, and following its windings, is a small canal,
called by Rosenthal the canalis spiralis modioli. In the recent state, the osseous
zone is continued to the opposite wall of the canal by a membranous and muscular
layer (membranous zone), so as to form a complete partition in the tube of the
cochlea. Two passages, or scalte, are thus formed, by a division of the canal of
the cochlea into two. One, the scala tympani, is closed below by the membrane
of the fenestra rotunda; the other, the scala vestibuli, communicates, by an
oval aperture, with the vestibule. Near the termination of the scala vestibuli,
close by the fenestra rotunda, is the orifice of the aqueductus cochleae. The
scal^e communicate, at the apex of the cochlea, by an opening common to both,
the helicotrema, which exists in consequence of the deficiency of the lamina
spiralis in the last half coil of the canal.
In structure, the membranous zone is a transparent glassy lamina, presenting
near its centre a number of minute transverse lines, which radiate outwards, and
give it a fibrous appearance; and at its circumference, where connected with the
outer wall of the spiral canal, it is composed of a semi-transparent structure, the
Cochlearis muscle (Todd and Bowman), connective tissue (Kolliker).
The vestibular surface of the osseous portion of the lamina spiralis is covered,
for about the outer fifth of its surface, with a thin layer, resembling cartilage in
texture. It is described as the denticulate lamina (Todd and Bowman), from
its presenting a series of wedge-shaped teeth which form its free margin, and
which project into the vestibular scalfe.
The Inner surface of the osseous labyrinth is lined by an exceedingly thin
fibro-serous membrane, analogous to a periosteum, from its close adhesion to the
inner surface of these cavities, and performing the office of a serous membrane by
its free surface. It lines the vestibule, and from this cavity is continued into the
semicircular canals and the scala vestibuli of the cochlea, and through the heli-
cotrema into the scala tympani. Two delicate tubular processes are prolonged
along the aqueducts of the vestibule and cochlea, to the inner surface of the dura
mater. This membrane is continued across the fenestra ovalis and rotunda, and
consequently has no communication with the lining membrane of the tympanum.
Its attached surface is rough and fibrous, and closely adherent to the bone; its
free surface is smooth and pale, covered with a layer of epithelium, and secretes a
thin, limpid fluid, the aqua labyrinthi {perilymph (Blainville), liquor Cotunnii).
In the vestibule and semicircular canals, it separates the osseous from the mem-
branous labyrinth; but in the cochlea it lines the two surfaces of the bony lamina
spiralis; and being continued from its free margin across the canal to its outer
wall, forms the lamina spiralis membrnnacea, serving to complete the separation
between the two scal^e.
p i> 2
58o
ORGANS OF SENSE.
The Membranous Labyrinth.
The membranous labyrinth (fig. 295) is a closed membranous sac, containing
fluid, upon which the ultimate ramifications of the auditory nerve are distributed.
295- — The Membranous Labyrinth detached (enlarged).
Oiolitlics
teen ihroaoA ihew
N. tc Cochlea
It has the same general form as the vestibule and semicircular canals, in which it
is enclosed; but is considerably smaller, and separated from their lining membrane
by the perilymph.
The Vestibular "portion consists of two sacs, the utricle and the saccule.
The Utricle is the larger of the two, of an oblong form, compressed laterally,
and occupies the upper and back part of the vestibule, lying in contact with the
fovea semi-elliptica. Numerous filaments of the auditory nerve are distributed to
the wall of this sac; and its cavity communicates, behind, with the membranous
semicircular canals by five orifices.
The Sacculus is the smaller of the two vestibular sacs: it is globular in form, lies
in the fovea hemispherica, near the opening of the vestibular scala of the cochlea,
and receives numerous nervous filaments, which enter from the bottom of the
depression in which it is contained. Its cavity is apparently distinct from that
of the utricle.
The Membranous Semicircular Canals are about one-third the diameter of the
osseous canals, but in number, shape, and general form they are precisely similar;
they are hollow, and open by five orifices into the utriculus, one being common to
two canals. Their ampullas are thicker than the rest of the tubes, and nearly fill
the cavities in which they are contained.
The membranous labyrinth is held in its position by the numerous nervous fila-
ments distributed to the utriculus, the sacculus, and to the ampulla of each canal.
These nerves enter the vestibule through the minute apertures on its inner wall.
Structure. The wall of the membranous labyrinth is semi-transparent, and con-
sistg of three layers. The outer layer is a loose and flocculent tissue, containing
MEMBRANOUS LABYRINTH. 581
blood-vessels and numerous pigment cells, analogous to those in the choroid. The
middle layer, thicker and more transparent, bears some resemblance to the hyaloid
membrane, but it presents in parts marks of longitudinal fibrillation and elongated
nuclei on the addition of acetic acid. The in?ier layer is formed of polygonal
nucleated epithelial cells, which secrete the fluid contained in its interior.
The E?idolymph {liquor Scarpa) is a limpid serous fluid, which fills the mem-
branous labyrinth; in composition, it closely resembles the perilymph.
The Otoliths are two small rounded bodies, consisting of a mass of minute
crystalline grains of carbonate of lime, held together in a mesh of delicate fibrous
tissue, and contained in the wall of the utriculus and sacculus, opposite the distri-
bution of the nerves. A calcareous material is also, according to Bowman,
sparingly scattered in the cells lining the ampulla of each semicircular canal.
The Arteries of the Labyrinth are the internal auditory, from the basilar or
superior cerebellar, the stylo-mastoid, from the posterior auricular, and, occasion-
ally, branches from the occipital. The internal auditory divides at the bottom of
the internal meatus into two branches, cochlear and vestibular.
The cochlear branch subdivides into from twelve to fourteen twigs, which
traverse the canals in the modiolus, and are distributed, in the form of a capillary
network, in the substance of the lamina spiralis.
The vestibular branches accompany the nerves, and are distributed, in the form
of a minute capillary network, in the substance of the membranous labyrinth.
The Veins of the vestibule and semicircular canals accompany the arteries, and
receiving those of the cochlea at the base of the modiokis, terminate in the supe-
rior petrosal sinus.
The Auditory Nerve, the special nerve of the sense of hearing, divides, at the
bottom of the internal auditory meatus, into two branches, the cochlear and vesti-
bular. The trunk of the nerve, as well as the branches, contains numerous gan-
glion cells with caudate prolongations.
The Vestibular Nerve, the most posterior of the two, divides into three
branches, superior, middle, and inferior.
The superior vestibular branch, the largest, divides into numerous filaments,
which pass through minute openings at the upper and back part of the cul-de-sac
at the bottom of the meatus, and entering the vestibule, are distributed to the
utricle, and to the ampulla of the external and superior semicircular canals.
The middle vestibular branch consists of numerous filaments, which enter the
vestibule by a smaller cluster of foramina, placed below those above mentioned,
and which correspond to the bottom of the fovea hemispherica; they are distri-
buted to the sacculus.
The inferior and smallest branch passes backwards in a canal behind the fora-
mina for the nerves of the sacculus, and is distributed to the ampulla of the posterior
semicircular canal.
The nervous filaments enter the ampullary enlargement at a deep depression seen
on their external surface, and a corresponding elevation is seen within, the nerve
fibres ending in loops and in free extremities. In the utricle and saccule the
nerve fibres spread out, some blending with the calcareous matter, others radi-
ating on the inner surface of the wall of each cavity, becoming blended with a
layer of nucleated cells, and tei'minating in a thin fibrous film.
The Cochlear Nerve divides into numerous filaments at the base of the mo-
diolus, which ascend along its canals, and then bending outwards at right angles,
pass between the plates of the bony lamina spiralis close to its tympanic surface.
Between the plates of the spiral lamina, the nerves form a plexus, which contains
ganglion cells; and from the margin of the osseous zone, branches from this plexus
are distributed to the membranous part of the septum, where they are arranged
in small conical-shaped bundles, parallel with one another. The filaments which
supply the apical portion of the lamina spiralis are conducted to this part through
the tubulus centralis modioli.
Organs of Digestion.
THE Apparatus for the digestion of the food consists of the alimentary canal,
and of certain accessory organs.
The Alimentary Canal is a musculo-membranous tube, about thirty feet in
length, extending from the mouth to the anus, and lined throughout its entire
extent by mucous membrane. It has received different names in the various parts
of its course: at its commencement, which comprises the mouth, we find every
provision for the mechanical division of the food (mastication), and for its admix-
ture with a peculiar fluid secreted by the salivary glands (insalivation); beyond
this is the phaiynx and the oesophagus, the organs of deglutition, which convey the
food into that part of the alimentary canal (the stomach) in which the principal
chemical changes occur; in the stomach the reduction and solution of the food takes
place; in the small intestines, the nutritive principles of the food (the chyle), by
its admixture with the bile and pancreatic fluid, are separated from that portion
Avhich passes into the large intestine, and which is expelled from the system.
Alimentary Canal.
[ Duodenum.
Mouth. Small intestine { Jejunum.
Pharynx. (. Ileum.
CEsophagus. [ Caecum.
Stomach. Large intestine { Colon.
I Rectum.
Accessory Organs.
Teeth.
{Parotid. Liver.
Submaxillary. Pancreas.
Sublingual. Spleen.
The Mouth (fig. 2g6) is placed at the commencement of the alimentary canal;
it is a nearly oval-shaped cavity, in which the mastication of the food takes place.
It is bounded in front by the lips; laterally, by the cheeks and alveolar process
of the upper and lower jaw; above, by the hard palate and teeth of the upper
jaw; below, by the tongue, the mucous membrane stretched between the under
surface of this organ and the inner surface of the jaws, and by the teeth of the
lower jaw; behind, by the soft palate and fauces.
The mucous membrane lining the mouth is continuous with the integument at
the free margin of the lips, and with the mucous lining of the fauces behind; it is
of a pink rose tinge during life, and very thick where it covers the hard parts
bounding this cavity.
The Lips are two fleshy folds, which surround the orifice of the mouth, formed
externally of integument, intei-nally of mucous membrane, between which is found
the Orbicularis oris muscle, the coronary vessels, some nerves, areolar tissue, fat,
and numerous small labial glands. The inner surface of each lip is connected in
the middle line to the gum of the corresponding jaw by a fold of mucous mem-
brane, the frcenum lahii superioris and inferioris, the former being the larger of
the two.
T\iG labial glands are situated between the mucous membrane and the Orbicularis
THE MOUTH, LIPS, AND CHEEKS.
583
oris, around the orifice of the mouth. They are rounded in form, about the size
of a small pea, their ducts opening by small orifices upon the mucous membrane.
In structure, they resemble the other salivary glands.
The Cheeks form the sides of the face, and are continuous in front with the
lips. They are composed, externally, of integument; internally, of mucous mem-
brane; and, between the two, is a muscular stratum, besides a large quantity of
fat, areolar tissue, vessels, nerves, and buccal glands.
The mucous membrane lining the cheek, is reflected above and below upon the
gums, and is continuous behind with the lining membrane of the soft palate.
Opposite the second molar tooth of the upper jaw is a papilla, the summit of
296. — Sectional View of the Nose, Mouth, Pharynx, etc.
which presents the minute aperture of the duct of the parotid gland. The prin-
cipal muscle of the cheek is the Buccinator; but numerous others enter into its
formation, viz., the Zygomatici, Masseter, and the Platysma myoides.
The buccal glands are placed between the mucous membrane and Buccinator
muscle: they are similar in structure, but smaller, than the labial glands. Two
or three, of larger size than the rest, are placed between the Masseter and
Buccinator muscles: their ducts open into the mouth, opposite the last molar
tooth. They are called molar glands.
The Gums are composed of a dense fibrous tissue, closely connected to the
584
ORGANS OF DIGESTION.
periosteum of the alveolar processes, and surrounding the necks of the teeth.
They are covered by smooth and vascular mucous membrane, which is remarkable
for its limited sensibility. Around the necks of the teeth, this membrane
presents numerous fine papillae; and from this point it is reflected into the
alveolus, where it is continuous with the periosteal membrane lining that
cavity.
The Teeth.
The human subject is provided with two distinct sets of teeth, which make
their appearance at different periods of life. The first set appear in childhood,
and are called the temporary, deciduous, or Tnilk teeth. The second set, which
also appear at an early period, continue until old age, and are named ■permanent.
The Temporary Teeth are twenty in number; four incisors, two canine, and
four molars, in each jaw.
The Permanent Teeth are thirty- two in number; four incisors, two central and
two lateral, two canine, four bicuspids, and six molars, in each jaw.
General characters. Each tooth consists of three portions: the crown, or body.
MoU
297. — The Permanent Teeth. External View.
£icuspids
Wisdom' tnath
Vanine Jneistor
Fana
1 JVecA
LotveT Jaiv
Molars
which projects above the gum; the root, or fang, entirely concealed within the
alveolus; and the neck, the constricted portion between the other two.
The roots of the teeth are firmly implanted within the alveoli: these depressions
are lined with periosteum, which is reflected on to the tooth at the point of the
fang, and covers it as far as the neck. At the margin of the alveolus, the
periosteum becomes continuous with the fibrous structure of the gums.
TEETH. 585
Permanent Teeth.
The Incisors, or cutting teeth, are so named from their presenting a sharp,
cutting edge, adapted for cutting the food. They are eight in number, and form
the four front teeth in each jaw.
The crown is directed vertically, is wedge-like in form, being bevelled at the
expense of its posterior surface, so as to terminate in a sharp, horizontal cutting
edge, which, before being subject to attrition, presents three small prominent
points. It is convex, smooth, and highly polished in front; slightly concave
behind, where it is frequently marked by slight longitudinal furrows.
The neck is constricted.
The fang is long, single, conical, transversely flattened, thicker before than
behind, and slightly grooved on each side, in the longitudinal direction.
The Incisors of the Upper Jaw are altogether larger and stronger than those
of the lower jaw. They are directed obliquely downwards and forwards. The
two central ones are larger than the two lateral, and their free edges sharp and
chisel-like, being bevelled at the expense of their posterior edge: the root is more
rounded.
The Incisors of the Lower Jaw are smaller than the upper: the two central
ones are smaller than the two lateral, and are the smallest of all the incisor
teeth.
The Canine Teeth (cuspidati) are four in number, two in the upper, and
two in the lower jaw; one being placed behind each lateral incisor. They are
larger and stronger than the incisors, especially the root, which sinks deeply into
the jaw, and causes a well marked prominence upon its surface.
The croivn is large and conical, very convex in front, a little hollowed and
uneven posteriorly, and tapering to a blunted point, or cusp, which rises above
the level of the other teeth.
The root is single, but longer and thicker than that of the incisors, conical in
form, compressed laterally, and marked by a slight groove on each side.
The Upper Canine Teeth (vulgarly called eye-teeth), are larger and longer
than the two lower, and situated a little behind them.
The Loioer Canine Teeth are placed in front of the upper, so that their sum-
mits correspond to the interval between the upper canine tooth and the neigh-
bouring incisor.
The Bicuspid Teeth (small, or false molars), are eight in number, four in each
jaw, two being placed immediately behind each of the canine teeth. They are
smaller and shorter than the canine.
The crown is compressed from without inwards, and surmounted by two pyra-
midal eminences, or cusps, separated by a groove, hence their name, bicuspidate.
The outer of these cusps is larger and more prominent than the inner.
The neck is oval.
The root is generally single, compressed, and presenting a tendency to become
double, as seen from the deep groove on each side. The apex is generally bifid.
The Upper Bicuspids are larger, and present a greater tendency to the
division of their roots than the lower: this is especially marked in the second
upper bicuspid.
The Molar Teeth {multicuspidati, true, or large molars), are the largest of
the permanent set, and are adapted, from the great breadth of their crowns,
for grinding and pounding the food. They are twelve in number, six in each
jaw, three being placed behind each of the posterior bicuspids.
The crown is nearly cubical in form, rounded on each of its lateral surfaces,
flattened in front and behind; the upper surface being surmounted by four or five
tubercles, or cusps, (four in the upper, five in the lower molars), separated from
each other by a crucial depression, hence their name, multicuspidati.
586
ORGANS OF DIGESTION.
The neck is distinct, large, and rounded.
The root is subdivided into from two to five fangs, each of which presents an
aperture at its summit.
The First Molar Tooth is the largest and broadest of all: its crown has usually
five cusps, three outer and two inner. In the upper jaw, the root consists of
three fangs, widely separated from one another, two being external, the other
internal. The latter is the lai'gest and the longest, slightly grooved, and some-
times bifid. In the lower jaw, the root consists of two fangs, one being placed in
front, the other behind: they axe both compressed from before backwards, and
grooved on their contiguous faces, indicating a tendency to division.
The Second Molar is a little smaller than the first.
The crown has four cusps in the upper, and five in the lower jaw.
The root has three fangs in the upper jaw, and two in the lower, the characters
of which are similar to the preceding tooth.
The Third Molar Tooth is called the wisdom tooth (dens sapientice), from its
late appearance through the gum. It is smaller than the others, and its axis is
directed inwards.
The croicn is small and rounded, and furnished with three tubercles.
The root is generally single, short, conical, slightly curved, and grooved so as
to present traces of a subdivision into three fangs in the upper, and two in the
lower jaw.
Temporary Teeth.
The temporary, or milk teeth, are smaller, but resemble in form those of the
permanent set. The hinder of the two temporary molars is the largest of all the
298.— The Temporary, or Milk Teeth.
External View.
Motors Canine Incisors
Loiver Jcliv
■I'a.ng
milk teeth, and is succeeded by the second permanent bicuspid. The first upper
molar has only three cusps, two external, one internal: the second upper molar
has four cusps. The first lower molar has four cusps: the second lower molar
has five. The fangs of the temporary molar teeth are smaller, and more diverging
than those of the permanent set; but, in other respects, bear a strong resemblance
to them.
STRUCTURE OF TEETH.
587
299. — Vertical Section
of a Molar Tooth.
- Ci^own
-Neck
-Jfa
300. — Vertical Section of a Bicus-
pid Tooth (magnified).
Structure. On making a vertical section of a tooth (lig. 299), a hollow cavity
will be found in the interior. This cavity is situated at the base of the crown, and
is continuous with a canal which traverses the centre of
each fang, and opens by a minute orifice at its extremity.
The shape of the cavity corresponds somewhat with
that of the tooth: it forms what is called the pulp
cavity, and contains a soft, highly vascular, and sensitive
substance, the dental pulp. The pulp is richly supplied
with vessels and nerves, which enter the cavity through
the small aperture at the point of each fang,
The solid portion of the tooth consists of three distinct
structures, viz. ivory (tooth-bone, or dentine), which foi-ms
the larger portion of the tooth; enamel, which covers the
exposed part, or crown; and the cortical substance, or
cement {crusta petrosd), which is disposed as a thin layer on the surface of the
fang.
The Ivory, or dentine (fig. 300), forms the principal mass of a tooth; in its
central part is the cavity enclosing the pulp. It is a modification of the osseous
tissue, from which it differs, however, in struc-
ture and chemical composition. On examination
with the microscope, it is seen to consist of a
number of minute wavy and branching tubes,
having distinct parietes. They are called the
dental tuhuli, and are imbedded in a dense homo-
geneous substance, the intertubular tissue.
The Dental Tuhuli are placed parallel with
one another, and open at their inner ends into the
pulp cavity. They pursue a wavy and undulating
course towards the periphery. The direction of
these tubes varies; they are vertical in the upper
portion of the crown, oblique in the neck and
upper part of the root, and towards the lower
part of the root they are inclined downwards.
The tubuli, at their commencement, ai's about
"4 3^0^ *^^ ^^ inch in diameter; in their course they
divide and subdivide dichotomously, so as to give
to the cut surface of the dentine a striated ap-
pearance. From the sides of the tubes, espe-
cially in the fang, ramifications of extreme mi-
nuteness are given off, which join together in
loops in the intertubular substance, or terminate
in small dilatations, from which branches are given
off. Near the periphery of the dentine, the finer ramifications of the tubuli termi-
nate in a somewhat similar manner. In the fang, these ramifications occasionally
pass into the crusta petrosa. The dental tubuli have comparatively thick walls,
and contain, according to Mr. Tomes, slender cylindrical prolongations of the
pulp-tissue.
The Intertubular Substance is translucent, finely granular, and contains the
chief part of the earthy matter of the dentine. After the earthy matter has been
removed, by steeping a tooth in weak acid, the animal basis remaining is described
by Henle as consisting of bundles of pale, granular, flattened fibres, running
parallel with the tubes; but by Mr. Nasmyth as consisting of a mass of brick-
shaped cells surrounding the tubules. By Czermack and Mr. Salter it is sup-
posed to consist of laminse which run parallel with the pulp cavity, across the
direction of the tubes.
Chemical Composition. According to Berzelius and Bibra, dentine consists of
28 parts of animal, and 72 of earthy matter. The animal matter is resolvable by
/
-JPwuff
588 ORGANS OF DIGESTION.
boiling into gelatin. The earthy matter consists of phosphate of lime, carbo-
nate of lime, fluoride of calcium, a trace; and phosphate of magnesia and other
salts.
The Enamel is the hardest and most compact part of a tooth, and forms a thin
crust over the exposed part of the crown, as far as the commencement of the
fang. It is thickest on the grinding surface of the crown, until worn away by
attrition, and becomes thinner towards the neck. It consists of a congeries of
minute hexagonal rods. They lie parallel with one another, resting by one
extremity upon the dentine, which presents a number of minute depressions for
their reception ; the other extremity forming the free surface of the crown.
These fibres are directed vertically on the summit of the crown, horizontally at
the sides; they are about the 5-5V0 ^^ ^^ ^^*^^ ™ diameter, and pursue a more or
less wavy course, which gives to the cut surface of the enamel a series of con-
centric lines.
Numerous minute interstices intervene between the enamel-fibres near their
dentinal surface, a provision calculated to allow of the permeation of fluids from
the dentinal tubuli into its substance. The enamel-rods consist of solid hexago-
nal or four-sided prisms, connected by their surfaces and ends, and filled with
calcareous matter. If the latter is removed, by weak acid, from newly-formed or
growing enamel, it will be found to present a network of delicate prismatic cells
of animal matter.
Chemical Composition. According to Bibra, enamel consists of 96*5 per cent,
of earthy matter, and 3*5 per cent, of animal matter. The earthy matter consists
of phosphate of lime, with traces of fluoride of calcium; carbonate of lime, phos-
phate of magnesia and other salts.
The Cortical Substance, or cement {crusta petrosd), is disposed as a thin
layer on the roots of the teeth, from the termination of the enamel, as far as the
apex of the fang, where it is usually very thick. In structure and chemical com-
position, it resembles bone. It contains, sparingly, the lacunae and canaliculi
which characterise true bone: those placed near the surface have the canaliculi
radiating from the side of the lacunae towards the periodontal membrane; and
those more deeply placed, join with the adjacent dental tubuli. In the thicker
portions of the crusta petrosa, the lamella and Haversian canals peculiar to bone
are also found. As age advances, the cementum increases in thickness, and gives
rise to those bony growths, or exostoses, so common in the teeth of the aged; the
pulp cavity becomes also partially filled up by a hard substance, intermediate in
structure between dentine and bone {osteo-dendne, Owen ; secondary dentine,
Tomes). It appears to be formed by a slow conversion of the dental pulp, which
shrinks or even disappears.
Development of the Teeth (figs. 301 to 306).
According to the observations of Arnold and Goodsir, the teeth are developed
from the mucous membrane covering the edges of the maxillary arches. About
the sixth week of foetal life (fig. 301), the mucous membrane covering the edge
of the upper jaw, presents a semicircular depression or groove : this is the pri-
mitive dental groove (Goodsir), from the floor of which the germs of the ten
deciduous or milk-teeth are developed. The germ of each tooth is formed by a
conical elevation or papilla of mucous membrane (fig. "^oa); it constitutes the
rudimentary pulp of a milk-tooth. The germs of the milk-teeth make their
appearance in the following order: at the seventh week, the germ of the first
deciduous molar of the upper jaw appears ; at the eighth week, that for the
canine tooth is developed; the two incisor papilla appear about the ninth week
(the central preceding the lateral); lastly, the second molar papilla is seen at the
tenth week, behind the anterior molar. The teeth of the lower jaw appear rather
later, the first molar papilla being only just visible at the seventh week; and
the tenth papilla not being developed before the eleventh week. This completes
the first or papillary stage of their development.
DEVELOPMENT OF TEETH.
589
The dental groove now becomes contructed,
its margins tliickened and prominent, and the
groove is converted into follicles, for the i-e-
ception of the papillas, by the growth of mem-
branous sejDta, which pass across the groove
between its borders (fig. 303)* The follicles
by this means become the alveoli, lined by
periosteum, from the bottom of which a pro-
cess of the mucous membrane of the gum
rises, which is the germ of the future tooth.
The follicle for the first molar is complete
about the tenth week, the canine follows next,
succeeded by the follicles for the incisors,
which are completed about the eleventh or
twelfth week; and, lastly, the follicle of the
posterior deciduous molar is completed about
the fourteenth week. These changes consti-
tute the second or follicular stage.
About the thirteenth week, the papillae
begin to grow rapidly, project from the folli-
cles, and assume a form corresponding with
that of the future teeth; the follicles soon
become deeper, and from their margins small
membranous processes, or opercula, are de-
veloped, which, meeting, unite and form a lid
to the now closed cavity (fig. 304). These
processes correspond in shape to the form of
the crown of the tooth, and in number to
the tubercles on its surface. The follicles of
the incisor teeth have two opercula, the canine
three, and the molars four or five each. The
follicles are thus converted into dental sacs,
and the contained papillae become pulps. The
lips of the dental groove gradually advance
over the follicles from behind forwards, and,
uniting, gradually obliterate it. This com-
pletes the third or saccular stage, which takes
place about the end of the fifteenth week.
The deep portion of the primitive dental
groove is now closed in; but the more super-
ficial portion, near the surface of the gum,
still remains open; it is called by Mr. Goodsir,
the secondary dental groove : from it are de-
veloped the ten anterior permanent teeth.
About the fourteenth week, certain lunated
depressions are formed, one behind each of
the sacs of the rudimentary milk-teeth. They
are ten in number in each jaw, and are
formed successively from before backwards;
they are the rudimentary follicles of the four
permanent incisors, the two canine, and the
four bicuspids. As the secondary dental groove
closes in, these follicles become closed cavities
of reserve (fig. 304). The cavities soon elongate,
and recede from the surface into the sub-
stance of the gum, behind the sacs of the
Development of Teeth.
Flo. 301.
F I C . 3 02'.
F I C . 304.
FIG. 305.
iv Cnvitu ofJRese^ve
Fl C. 306j
^efimctvte^^ 'feat^
I
590 ORGANS OF DIGESTION.
deciduous teeth, and a papilla projects from the bottom of each, which is the
germ of the permanent tooth: at the same time, one or more opercular folds are
developed from the sides of the cavity; and these uniting, divide it into two
portions; the lower portion containing the papilla of the permanent tooth, the
upper narrower portion becoming gradually contracted in the same way that the
primitive dental groove was obliterated over the sacs of the deciduous teeth.
The six posterior permanent teeth in each jaw, three on each side, arise from
successive extensions backwards of the posterior part of the primitive dental
groove. During the fourth month, that portion of the dental groove which lies
behind the last temporary molar follicle remains open, and from it is developed
the papilla, the rudiment of the first permanent molar. The follicle in which
it is contained becomes closed by its operculum, and the upper part of the
now-formed sac elongates backwards to form a cavity of reserve, in which the
papilla of the second permanent molar appears at tlie seventh month after birth.
After a considerable interval, during which the sacs of the first and second
permanent molars have considerably increased in size, the remainder of the
cavity of reserve presents for the last time a series of changes similar to the
preceding, and gives rise to the sac and papilla of the wisdom-tooth, which
appears at the sixth year.
Growth of the Teeth. As soon as the dental sacs are formed by the closing in
of the follicles, they gradually enlarge, as well as their contained papillse. The
sacs consist of two layers: an internal highly vascular layer, lined by epithelium;
and an external or areolo-fibrous membrane, analogous to the corium of the
mucous membrane.
The Dental Pulps soon become moulded to the form of the future teeth, and are
adherent by their bases to the bottom of the dental sacs ; in the case of the molars,
the base of the pulp is divided into two or more portions, which form the future
fangs. During the fourth or fifth month of fcetal life, a thin lamina or cap of dentine
is formed on the most prominent point of the pulp of all the milk-teeth. In the
incisor and canine teeth, this newly-formed lamina has the form of a hollow cone;
in the molar teeth, as many sejDarate laminae are found, as there are eminences
upon its crown. These laminae grow at the expense of the pulp-substance,
increasing in breadth by a growth around their margins, and in thickness by a
similar formation in its substance ; the separate cones (if a molar tooth) ultimately
coalesce, and the crown is completely formed. The pulp now becomes constricted,
so as to form the cervix; and the remaining portion becomes narrow and elon-
gated, to form the fang. The growth of dentine takes place from the surface
towards the interior, until nothing but the small cavitas pulpcB remains in the
centre of the tooth, communicating by the aperture left at the point of each fang,
with the dental vessels and nerves.
As soon as the formation of the dentine has commenced, there is developed
from the inner wall of the dental sac, a soft pulpy mass, the enamel organ, which
is intimately united to the surface of the dental pulp, or its cap of dentine. It
consists of a mesh of fibres, elastic and spongy, containing within its reticulations
fluid albumen; and at the point of junction of each fibre, a transparent nucleus is
visible. The surface towards the dentinal pulp is covered by a layer of elongated
nucleated cells, the enamel memhrane. The deposition of the enamel takes place
on the outer surface of the cap of dentine.
The Cementum appears to be formed, at a later period of life, by the perio-
dontal membrane, extending from the margin of the enamel downwards.
Eruption. When the calcification of the different tissues of the tooth is suffi-
ciently advanced to enable it to bear the pressure to which it will be afterwards
subjected, its eruption takes place, the tooth making its way through the gum.
The gum is absorbed by the pressure of the crown of the tooth against it, which
is itself pressed up by the increasing size of the fang. Concurrent with this, the
septa between the dental sacs, at first fibrous in structure, soon ossify, and consti-
PALATE.
591
tute the alveoli; these firmly embrace the necks of the teeth, and aiford them a
solid basis of support.
The eruption of the temporary teeth commences at the seventh month, and
is complete about the end of the second year, those of the lower jaw preceding
the upper.
The periods for the eruption of the temporary set are :
7th month, central incisors. 14th to 20th month, canine.
7th to 10th month, lateral incisors. i8th to 36th month, posterior molars,
1 2th to 14th month, anterior molars.
Calcification of the permanent teeth commences a little before birth, and pro-
ceeds in the following order in the upper jaw, in the lower jaw appearing a little
earlier. First molar, five or six months; the central incisor a little later; lateral
incisors and canine, about the eighth or ninth month; the bicuspids at the second
year; second molar, five or six years; wisdom-tooth, about twelve years.
Previous to the permanent teeth penetrating the gum, the bony partitions
separating their sacs from the deciduous teeth are absorbed, the fangs of the
temporary teeth disappear, and the permanent teeth become now placed under the
loose crowns of the deciduons teeth ; the latter finally become detached, when
the permanent teeth take their place in the mouth.
The eruption of the pei'manent teeth takes place at the following periods, the
teeth of the lower jaw preceding those of the upper by a short interval :
6^ years, first molars. 1 0th year, second bicuspid.
7th year, tAvo middle incisors. llth to I2th year, canine.
8th year, tAvo lateral incisors. 1 2th to 13th year, second molars.
9th year, first bicuspid. 17th to 2 1st year, wisdom-teeth.
The Palate,
The Palate forms the roof of the mouth; it consists of two portions, the hard
palate in front, the soft palate behind.
The Hard Palate is bounded in front and at the sides by the alveolar arches
and gums; behind, it is continuous with the soft palate. It is covered by a dense
structure, formed by the periosteum and mucous membrane of the mouth, which
are intimately adherent. Along the middle line is a linear ridge or raphe, which
terminates anteriorly in a small papilla, corresponding with the inferior opening
of the anterior palatine fossa. This papilla receives filaments from the naso-
palatine and anterior palatine nerves. On either side and in front of the raphe,
the mucous membrane is thick, pale in colour, and corrugated; behind, it is thin,
smooth, and of a deeper colour: it is covered with squamous epithelium, and fur-
nished with numerous glands (palatal glands), which lie between the mucous
membrane and the surface of the bone.
The Soft Palate ( Velum ■pendulum palati) is a moveable fold, suspended from
the posterior border of the hard palate, forming an incomplete septum betAveen the
mouth and pharynx. It consists of a fold of mucous membrane, enclosing mus-
cular fibres, an aponeurosis, vessels, nerves, and mucous glands. When occupying
its usual position (a relaxed pendent state), its anterior surface is concave, con-
tinuous with the roof of the mouth, and marked by a median ridge or raphe,
which indicates its original separation into two lateral halves. Its posterior
surface is convex, and continuous with the mucous membrane covering the floor
of the posterior nares. Its upper border is attached to the posterior margin of
the hard palate, and its sides are blended with the pharynx. Its lower border is
free.
Hanging from the middle of its lower border is a small conical-shaped pendu-
lous process, the v.vv.la ; and arching outwards a-nd dowuAvards from the base of
592 ORGANS OF DIGESTION.
the uvula on each side, are two curved folds of mucous membrane, containing
muscular fibres, called the arches or pillars of the soft palate.
The anterior pillar runs downwards and forwards to the side of the base of
the tongue, and is formed by the projection of the Palato-glossus muscle, covered
by mucous membrane.
The posterior pillars are more closely approximated and larger than the ante-
rior; they run downwards and backwards to the sides of the pharynx, and are
formed by the projection of the Palato-pharyngei muscles, covered by mucous
membrane. The anterior and jDosterior pillars are separated below by a triangular
interval, in which the tonsil is lodged.
The space left between the arches of the palate on the two sides is called the
isthmus of the fauces. It is bounded above by the free margin of the palate;
below, by the tongue; and on each side, by the pillars of the soft palate and
tonsils.
The mucous membrane of the soft palate is thin, and covered with squamous
epithelium on both surfaces, excepting near the orifice of the Eustachian tube,
where it is columnar and ciliated. The palatine glands form a continuous layer
on its posterior surface and around the uvula.
The aponeurosis of the soft palate is a thin but firm fibrous layer, attached
above to the hard palate, and becoming thinner towards the free margin of the
velum. It is blended with the aponeurotic tendon of the Tensor palati muscle.
The muscles of the soft palate are five on each side; the Levator palati, Tensor
palati, Palato-glossus, Palato-pharyngeus, and the Azygos uvulae. (See p. 213.)
The Tonsils (^Amygdalce) are two glandular organs, situated one on each side
of the fauces, between the anterior and posterior pillars of the soft palate. The
tonsils are of a rounded form, and vary considerably in size in diiferent individuals.
Externally the tonsil is in relation with the inner surface of the Superior con-
strictor, and with the internal carotid and ascending pharyngeal arteries, and
corresponds to the angle of the lower jaw. Its inner surface presents from
twelve to fifteen orifices, leading into small recesses, from which numerous folli-
cles branch out into the substance of the gland. These follicles are lined by a
continuation of the mucous membrane of the pharynx, covered with epithelium,
their walls being formed by a layer of closed capsules imbedded in the submucous
tissue. These capsules are analogous to those of Peyer's glands; they contain a
thick greyish secretion.
The arteries supplying the tonsil are the dorsalis linguae from the lingual,
the ascending palatine and tonsillar from the facial, the ascending pharyngeal
from the external carotid, and the descending palatine branch of the internal
maxillary.
The veins terminate in the tonsillar plexus, on the outer side of the tonsil.
The nerves are derived from the fifth, and from the glosso-pharyngeal.
The Salivary Glands.
The principal salivary glands communicating with the mouth, and pouring their
secretion into its cavity, are the parotid, submaxillary, and sublingual.
The Parotid Gland {irapa, near; ov9, oc)TO<i the ear) (fig. 307), so called from
being placed near the ear, is the largest of the' three salivary glands, varying in
weight from half an ounce to an ounce. It lies upon the side of the face, imme-
diately in front of the external ear. It is bounded above by the zygoma; below,
by the angle of the jaw, and by an imaginary line drawn between it and the Sterno-
mastoid muscle; anteriorly, it extends to a variable extent over the Masseter mus-
cle; posteriorly, it is bounded by the external meatus, the mastoid process, and
the insertion of the Sterno-mastoid muscle, which it slightly overlaps. Its outer
surface is smooth, covered by the integument, fascia, and Platysma, and has one
or two lymphatic glands resting on it. Its inner surface passes behind the ramus
SALIVARY GLANDS.
593
of the lower jaw, between it and the mastoid process. This portion of the gland
is deeply seated, extending above into the back part of the glenoid cavity; behind
and below, lying upon the styloid process and Styloid muscles; and, in front, ad-
vancing forwards beneath the ramus of the jaw, between the two Pterygoid
muscles. Embedded in its substance is the external carotid, which ascends behind
the ramus of the jaw; the posterior auricular artery emerges from it behind; the
temporal artery above; the transverse facial in front; and the internal maxillary
winds through it inwards, behind the neck of the jaw. Superficial to the carotid
307. — The Salivaiy Glands.
~"^
artery is the trunk formed by the union of the temporal and internal maxillary
veins. It is traversed, from before backwards, by the facial nerve and its
branches, which emerge at its anterior border; the great auricular nerve pierces
the gland to join the facial, and the temporal branch of the inferior maxillary
nerve lies above the upper part of the gland. The internal carotid artery and
internal jugular vein lie close to its deep surface.
The duct of the parotid gland (Steno's) is about two inches and a half in
length. It commences upon the inner surface of the cheek by a small orifice,
opposite the second molar tooth of the upper jaw; running obliquely for a short
distance beneath the mucous membrane, it pierces the Buccinator muscle, and
crosses the Masseter to the anterior border of the gland, in the substance of
which it subdivides into numerous branches. The direction of the duct corre-
sponds to a line drawn across the face about a finger's breadth below the zygoma,
from the lower part of the concha, to midway between the free margin of the
upper lip and the ala of the nose. While crossing the Masseter, it receives the
duct of a small detached portion of the gland, which occasionally exists as a sepa-
rate lobe, the socia parotidis. The parotid duct is dense, of considerable thick-
ness, and its canal about the size of a crow-quill: it consists of an external or
594 ORGANS OF DIGESTION.
fibrous coat, of considerable density, containing contractile fibres, and of an
internal or mucous coat, lined with columnar epithelium.
The arteries supplying the parotid gland are derived from the external carotid,
and from the branches of that vessel in or near its substance.
The veins follow a similar course.
The lymphatics terminate in the superficial and deep cervical glands, passing
in their course through two or three lymphatic glands, placed on its surface and
in its substance.
The nerves are derived from the carotid plexus of the sympathetic, the facial,
superficial temporal, and great auricular nerves.
The Submaxillary Gland is situated below the jaw, in the anterior part of the
submaxillary triangle of the neck. It is irregular in form, and weighs about two
drachms. It is covered in by the body of the lower jaw, the integument, Platysma,
and deep cervical fascia; and lies upon the Mylo-hyoid, Hyo-glossus, and Stylo-
glossus muscles, a portion of the gland passing beneath the posterior border of the
Mylo-hyoid. Behind, it is separated from the parotid gland by the stylo-maxil-
lary ligament, and from the sublingual gland in front by the Mylo-hyoid muscle.
The facial artery lies in a groove in its posterior and upper border.
The duct of the submaxillary gland (Wharton's) is about two inches in length,
and its walls much thinner than those of the parotid duct. It commences by a
narrow orifice on the summit of a small papilla, at the side of the frtenum linguae.
Passing between the sublingual gland and the Genio-hyo-giossus muscle, it runs
backwards and outwards between the Mylo-hyoid, and the Hyo-glossus and
Genio-hyo-glossus muscles, to the deep portion of the gland, where it divides
into numerous branches.
The arteries supplying the submaxillary gland are branches of the facial and
lingual. Its veins follow the course of the arteries. The nerves are derived from
the submaxillary ganglion, from the mylo-hyoid branch of the inferior dental, and
from the sympathetic.
The Suhliiigual Gland is the smallest of the salivary glands. It is situated
beneath the mucous membrane of the floor of the mouth, on either side of the
fraanum lingua, in contact with the inner surface of the lower jaw, close to the
symphysis. It is narrow, flattened, in shape somewhat like an almond, and
weighs about a drachm. It is in relation, above, with the mucous membrane;
beloio, with the Mylo-hyoid muscle; ^V^ front, with the depression on the side of
the symphysis of the lower jaw, and with its fellow of the opposite side; behind,
with the deep part of the submaxillary gland; and internally, with the Genio-hyo-
glossus, from which it is separated by the lingual neiwe and Wharton's duct. Its
excretory ducts (ductus Riviniani), from eight to twenty in number, open sepa-
rately into the mouth, on the elevated crest of mucous membrane, caused by the
projection of the gland, on either side of the frgenum linguae. One or more
join to form a tube which opens into, or near, the Whartonian duct: it is called
the duct of Bartholine.
Vessels and Nerves. The sublingual gland is supplied with blood from the
sublingual and submental arteries. Its nerves are derived from the gustatory.
Structure. The salivary are conglomerate glands, consisting of numerous lobes,
which are made up of smaller lobules, connected together by dense areolar tissue,
vessels, and ducts. Each lobule consists of numerous closed vesicles, Avhich open
into a common duct: the wall of each vesicle is formed of a delicate basement
membrane, lined by epithelium, and covered on its outer surface with a dense
capillary network. In the submaxillary and sublingual glands, the lobes are
larger and more loosely united than in the parotid.
The Pharynx.
The pharynx is that part of the alimentary canal which is placed behind the
nose, mouth, and larynx. It is a musculo-membranous sac, somewhat conical in
PHARYNX.
595
form, with the base upwards, and the apex downwards, extending from the base
of the skull to the cricoid cartilage in front, and the fifth cervical vertebra
behind.
The pharynx is about four inches and a half in length, and broader in the
transverse than in the antero-posterior diameter. Its greatest breadth is opposite
the cornua of the hyoid bone; its narrowest point at its termination in the
oesophagus. It is limited, above, by the basilar process of the occipital bone;
beloio, it is continuous with the oesophagus; posteriorly, it is connected by loose
areolar tissue with the cervical portion of the vertebral column, and the Longi
colli and Recti capitis antici muscles; anteriorly, it is incomplete, and is attached
in succession to the internal pterygoid plate, the pterygo-maxillary ligament, the
lower jaw, the tongue, hyoid bone, and larynx; laterally, it is connected to the
styloid processes and their muscles, and is in contact with the common and
internal carotid arteries, the internal jugular veins, and the eighth, ninth, and
sympathetic nerves, and above, with a small part of the Internal pterygoid
muscles.
It has seven openings communicating with it: the two posterior nares, the two
Eustachian tubes, the mouth, larynx, and oesophagus.
The posterior nares are the two large apertures situated at the upper part of
the anterior wall of the pharynx.
The two Eustachian tubes open one at each side of the upper part of the
pharynx, at the back part of the inferior meatus. Below the nasal fossie is the
posterior surface of the soft palate and uvula, the large aperture of the mouth, the
base of the tongue, the epiglottis, and the cordiform opening of the larynx.
The oesophageal opening is the lower contracted portion of the pharynx.
Structure. The pharynx is composed of three coats : a mucous coat, a muscular
layer, and a fibrous coat.
^\\^& fibrous coat is situated between the mucous and muscular layers, and is
called the pharyngeal aponeurosis. It is thick above, where the muscu.lar fibres
are wanting, and firmly connected to the basilar process of the occipital and
petrous portion of the temporal bones. As it descends, it diminishes in thickness,
and is gradually lost.
The mucous coat is continuous with that lining the Eustachian tubes, the nares,
the mouth, and the larynx. It is covered by columnar ciliated epithelium, as
low down as a level with the floor of the nares; below that point, it is of the
squamous variety.
The muscular coat has been already described (p. 21 1).
The pharyngeal glands are of two kinds, the simple, or compound follicular,
which are found in considerable numbers beneath the mucous membrane, through-
out the entire pharynx; and the racemose, which are especially numerous at the
upper part of the pharynx, and form a thick layer, across the back of the fauces,
between the two Eustachian tubes.
The (Esophagus.
The oesophagus is a membranous canal, about nine inches in length, extending
from the pharynx to the stomach. It commences at the lower border of the
cricoid cartilage, opposite the fifth cervical vertebra, descends along the front of
the spine, through the posterior mediastinum, passes through the Diaphragm, and,
entering the abdomen, terminates at the cardiac orifice of the stomach, opposite
the ninth dorsal vertebra. The general direction of the o3sophagus is vertical;
but it presents two or three slight curvatures in its course. At its commence-
ment, it is placed in the median line; but it inclines to the left side at the root of
the neck, gradually passes to the middle line again, and finally, again deviates
to the left, as it passes forwards to the oesophageal opening of the Diaphragm.
The oesophagus also presents an antero-posterior flexure, corresponding to the
curvature of the cervical and thoracic portions of the spine. It is the narrowest
Q Q 2
596 ORGANS OF DIGESTION.
part of the alimentarj canal, being most contracted at its commencement, and at
the point where it passes through the Diaphragm.
Relations. In the neck, the oesophagus is in relation, in front, with the trachea;
and, at the lower part of the neck, where it projects to the left side, with the
thyroid gland and thoracic duct ; behind, it rests upon the vertebral column
and Longus colli muscle; on each side, it is in relation with the common carotid
artery (especially the left, as it inclines to that side), and part of the lateral lobes
of the thyroid gland; the recurrent laryngeal nerves ascend between it and the
trachea.
In the thorax, it is at first situated a little to the left of the median line: it
passes across the left side of the transverse part of the aortic arch, descends in
the posterior mediastinum, along the right side of the aorta, until near the
Diaphragm, where it passes in front and a little to the left of this vessel, previous
to entering the abdomen. In is in relation, in front, with the trachea, the arch
of the aorta, the left bronchus, and the posterior surface of the pericardium;
behind, it rests upon the vertebral column, the Longus colli, and the intercostal
vessels; and below, near the Diaphragm, upon the front of the aorta; laterally, it
is covered by the pleurae; the vena azygos major lies on the right, and the
descending aorta on the left side. The pneumogastric nerves descend in close
contact with it, the right nerve passing down behind, and the left nerve in front
of it.
Surgical Anatomy. The relations of the CBSophagus are of considerable practical inter-
est to the surgeon, as he is frequently required, in cases of stricture of this tube, to
dilate the canal by a bougie, when it becomes of importance that its direction, and
relations to surrounding parts, should be remembered. In cases of malignant disease of
the oesophagus, where its tissues have become softened from infiltration of the morbid
dejDosit, the greatest care is requisite in directing the bougie through the strictured part,
as a false passage may easily be made, and the instrument may pass into the mediastinum,
or into one or the other pleural cavity, or even into the pericardium.
The student should also remember that contraction of the oesophagus, and consequent
symptoms of stricture, are occasionally produced by an aneurism of some part of the
aorta pressing upon this tube. In such a case, the passage of a bougie could only facilitate
the fatal issue.
It occasionally happens that a foreign body becomes impacted in the oesophagus, which
can neither be brought upwards nor moved downwards. When all ordinary means for its
removal have failed, excision is the only resource. This of course can only be performed
when it is not very low down. If the foreign body is allowed to remain, extensive inflam-
mation and ulceration of the oesophagus may ensue. In one case with which I am
acquainted, the foreign body ultimately penetrated the intervertebral substance, and
destroyed life by inflammation of the membranes and substance of the cord.
The operation of oesophagotomy is thus performed. The patient being placed upon his
back, with the head and shoulders slightly elevated, an incision, about four inches in
length, should be made on the left side of the trachea, from the thyroid cartilage down-
wards, dividing the skin and Platysma. The edges of the wound being separated, the Omo-
hyoid muscle, and the fibres of the Sterno-hyoid and Sterno-thyroid muscles, must be cut
through; the sheach of the carotid vessels being exposed, should be drawn outwards, and
retained in that position by retractors ; the oesophagus will then be exposed, and should
be divided over the foreign body, which should then be removed. Great care is necessary
to avoid woimdiug the thyroid vessels, the thyroid gland, and the laryngeal nerves.
Structure. The oesophagus has three coats: an external, or muscular; a middle,
or cellular; and an internal, or mucous coat.
The muscular coat is composed of two planes of fibres of considerable thick-
ness, an external longitudinal, and an internal circular.
The longitudinal fibres are arranged, at the commencement of the tube, in
three fasciculi ; one in front, which is attached to the vertical ridge on the posterior
surface of the cricoid cartilage; and one at each side, which are continuous with
the fibres of the Inferior constrictor: as they descend they blend together, and
form a uniform layer, which covers the outer surface of the tube.
The circular fibres are continuous above with the Inferior constrictor: their
direction is transverse at the upper and lower parts of the tube, but oblique in
the central part.
. ABDOMEN. 597
The muscular fibres in tlie upper part of tlie oesophagus are of a red colour,
and consist chiefly of the striped variety; but below, tliey consist entirely of the
involuntary muscular fibre.
The cellular coat connects loosely the mucous and muscular coats.
The mucous coat is thick, of a reddish colour above, and pale below. It is
loosely connected with the muscular coat, and disposed in longitudinal plicae,
which disappear on distension of the tube. Its surface is studded with minute
papillae, and it is covered throughout with a thick layer of squamous epithelium.
The (Esophageal Glands are numerous small compound glands, scattered
throughout the tube: they are lodged in the submucous tissue, and open upon the
surface by a long excretory duct. They are most numerous at the loAver part of
the tube, where they form a ring round the cardiac orifice.
The Abdomen.
The abdomen is the largest cavity of the trunk of the body, and is separated,
below, from the pelvic cavity by the brim of the pelvis. It is of an oval form,
the extremities of the oval being directed upwards and downwards; it is wider
above than below, and measures more in the vertical than in the transverse
diameter.
Boundaries. It is bounded in front and at the sides by the lower ribs, the
Transversales muscles, and venter ilii; behind, by the vertebral column, and the
Psoee and Quadrati lumborum muscles; above, by the Diaphragm; below, by the
brim of the pelvis. The muscles forming the boundaries of this cavity are lined
upon their inner surface by a layer of fascia, differently named according to the
part to which it is attached.
This cavity contains the greater part of the alimentary canal, some of the
accessory organs to digestion, the liver, pancreas, and spleen, and the kidneys and
supra-renal capsules. Most of these structures, as well as the wall of the cavity
in which they are contained, are covered by an extensive and complicated serous
membrane, the peritoneum.
The apertures found in the walls of the abdomen, for the transmission of struc-
tures to or from it, are the umbilicus, for the transmission (in the foetus) of the
umbilical vessels; the caval opening in the Diaphragm, for the transmission of
the inferior vena cava; the aortic opening, for the passage of the aorta, vena
azygos, and thoracic duct; and the oesophageal opening, for the oesophagus and
pneumogastric nerves. Belozv, are two apertures on each side ; one for the
passage of the femoral vessels, and the other for the transmission of the spermatic
cord in the male, and the round ligament in the female.
Regions. For convenience of description of the viscera, as well as of reference
to the morbid condition of the contained parts, the abdomen is artificially divided
into certain regions. Thus, if two circular lines are drawn round the body, the
one parallel with the cartilages of the ninth ribs, and the other with the highest
point of the crests of the ilia, the abdominal cavity is divided into three zones, an
upper, a middle, and a lower. If two parallel lines are drawn from the cartilage
of the eighth rib on each side, down to the centre of Poupart's ligament, each of
these zones is subdivided into three parts, a middle and two lateral.
The middle region of the upper zone is called the epigastric {eiTL, over;
<yaarr]p, the stomach); and the two lateral regions, the right and left hypochon-
driac {vTTO, under; ')(ovhpoL, the cartilages). The central region of the middle
zone is the umbilical; and the two lateral regions, the right and left lumbar.
The middle region of the lower zone is the hypogastric or pubic region; and the
lateral regions are the right and left inguinal. The parts contained in these
different regions are the following (fig. 308) :
598
ORGANS OF DIGESTION.
308
, — The Regions of the Abdomen and their Contents.
(Edge of Costal Cartilages in dotted outline.)
^ijnif
Right ■ Hypochondriac.
The right lobe of the
liver and the gall-bladder,
the duodenum, hepatic
flexure of the colon, upper
part of the right kidney,
and right supra-renal cap-
sule.
Right Lumbar.
Ascending colon, lower
part of the right kidney,
and some convolutions of
the small intestines.
Right Inguinal.
The CEecum, appendix
cseci, ureter, and spermatic
vessels.
Epigastric Region.
The middle and pylo-
ric end of the stomach,
left lobe of the liver and
lobus Spigelii, the hepa-
tic vessels, cseliac axis,
semilunar ganglia, pan-
creas, parts of the aorta,
vena cava, vena azygos,
and thoracic duct.
Umbilical Region.
The transverse colon,
part of the great omen-
tum and mesentery, trans-
verse part of the duode-
num, and some convolu-
tions of the jejunum and
ileum.
Hypogastric Region.
Convolutions of the
small intestines, the blad-
der in children, and in
adults if distended, and
the uterus during preg-
nancy.
Left Hypochondriac.
The splenic end of the
stomach, the spleen and
extremity of the pancreas,
the splenic flexure of the
colon, upper half of the
left kidney, and left su-
pra-renal capsule.
Left Lumbar.
Descending colon, lower
part of left kidney, and
some convolutions of the
small intestines.
Left Inguinal.
Sigmoid flexure of the
colon, ureter, and sper-
matic vessels.
599
The Peritoneum.
The peritoneum (nrepLreivetv, to extend around) is a serous membrane; and,
like all membranes of this class, a shut sac. In the female, however, it is not
completely closed, the Fallopian tubes communicating with it by their free
extremities ; and thus the serous membrane is continuous with their mucous
lining.
The peritoneum invests, more or less completely, all the viscera contained in
the abdominal and pelvic cavities, forming the visceral layer of the membrane;
it is then reflected upon the internal surface of the parietes of those cavities,
forming the parietal layer. The free surface of the peritoneum is smooth, moist,
and covered by a thin, squamous epithelium; its attached surface is rough, being
connected to the viscera and inner surface of the parietes by means of areolar tissue,
called the sub-peritoneal areolar tissue. The parietal portion is loosely connected
with the fascia lining the abdomen and pelvis; but more closely to the under
surface of the Diaphragm, and in the middle line of the abdomen.
In order to trace the reflections of this membrane (fig. 309) (the abdomen having
309.'
-The Eeflections of the Peritoneum, as seen in a vertical
Section of the Abdomen.
been opened), the liver should be raised upwards and supported in that position,
and the stomach should be depressed, when a thin membranous layer is seen pass-
ing from the transverse fissure of the liver, to the upper border of the stomach:
this is the lesser, or g astro-hepatic omentum. It consists of two thin, delicate
layers of peritoneum, an anterior and a posterior, between which are contained
6oo ORGANS OF DIGESTION.
the hepatic vessels and nerves. Of these two layers, the anterior should first be
traced, and then the posterior.
The anterior layer descends to the lesser curvature of the stomach, and covers
its anterior surface as far as the great curvature; it descends for some distance in
front of the small intestines, and, returning upon itself to the transverse colon,
forms the external layer of the great omentum; it then covers the under surface
of the transverse colon, and, passing to the back part of the abdominal cavity,
forms the inferior layer of the transverse meso-eolon. It may then be traced, in
front of the duodenum, the aorta, and vena cava, as far as the superior mesenteric
artery, along which it passes to invest the small intestines, and, returning to the
vertebral column, forms the mesentery ; whilst on either side, it covers the
ascending and descending colon, and is thus continuous with the peritoneum
lining the walls of the abdomen. From the root of the mesentery, it descends
along the front of the spine into the pelvis, and surrounds the upper part of the
rectum, which it holds in its position by means of a distinct fold, the meso-rectum.
Its course in the male and female now differs.
In the male, it forms a fold between the rectum and bladder, the recto-vesical
fold, and ascends over the posterior surface of the latter organ as far as its summit.
In the female, it descends into the pelvis in front of the rectum, covers a small
part of the posterior wall of the vagina, and is then reilected on to the uterus, the
fundus and body of which it covers. From the sides of the uterus, it is reflected
on each side to the wall of the pelvis, forming the broad ligaments; and from its
anterior surface it ascends upon the posterior wall of the bladder, as far as its
summit. From this point it may be traced, as in the male, ascending upon the
anterior parietes of the abdomen, to the under surface of the Diaj^hragm; from
which it is reflected upon the liver, forming the upper layer of the coronary, and
the lateral and longitudinal ligaments. It then (Tovers the upper and under sur-
faces of the liver, and at the transverse fissure becomes continuous with the
anterior layer of the lesser omentum, the point from whence its reflection was
originally traced.
The posterior layer of the lesser omentum descends to the lesser curvature of
the stomach, and covers its posterior surface as far as the great curvature; it
then descends for some distance in front of the small intestines, and, returning
upon itself to the transverse colon, forms the internal layer of the great omentum;
it covers the upper surface of the transverse colon, and, passing backwards to the
spine, forms the upper layer of the transverse meso-colon. Ascending in front
of the pancreas and crura of the diaphragm, it lines the back part of the under
surface of this muscle, from which it is reflected on to the posterior border of the
liver, forming the inferior layer of the coronary ligament. From the under sur-
face of the liver, it may be traced to the transverse fissure, where it is continuous
with the posterior layer of the lesser omentum, the point from whence its reflec-
tion was originally traced.
The space included in the reflections of this layer of the peritoneum, is called
the lesser cavity of the peritoneum, or cavity of tJie great omentum. It is bounded,
in front, by the lesser omentum, the stomach, and the descending part of the great
omentum; behind, by the ascending part of the great omentum, the transverse
colon, transverse meso-colon, and its ascending layer ; above, by the liver; and
beloWy by the folding of the great omentum. This space communicates with the
general peritoneal cavity through the foramen of Winslow, which is situated
behind the right free border of the lesser omentum.
The Foramen of Winsloio is bounded in front by the lesser omentum, enclos-
ing the vena portas and the hepatic artery and duct; behind, by the inferior
vena cava; above, by the lobus Spigelii; beloio, by the hepatic artery curving
forwards from the CEsliac axis.
This foramen is nothing more than a constriction of the general peritoneal
cavity at this point, caused by the hepatic and gastric arteries passing forwards
from the cseliac axis to reach their respective viscera.
PERITONEUM. 6oi
The viscera thus shown to be almost entirely invested by peritoneum are the
liver, stomach, spleen, first portion of duodenum, jejunum, and ileum, transverse
colon, sigmoid flexure, upper end of rectum, uterus, and ovaries.
Those partially covered by it are the descending and transverse portions of the
duodenum, the ctecum, the ascending and descending colon, the middle portion of
the rectum, and the upper part of the vagina and posterior wall of bladder.
Those receiving no investment from it, are the lower end of the rectum, the
neck, base, and anterior surface of the bladder, and the lower part of the
vagina.
Numerous folds are formed by the peritoneum, extending between the various
organs. These serve to hold them in position, and, at the same time, enclose the
vessels and nerves proceeding to each part. Some of the folds are called
ligaments, from their serving to support the organs in position. Others con-
stitute the mesenteries, which connect certain parts of the intestine with the
abdominal wall; and lastly, those are called omenta, which proceed from one
viscus to another.
The Ligaments, formed by folds of the peritoneum, include those of the liver,
spleen, bladder, and uterus. They are described with their respective organs.
The Omenta are the lesser omentum, the great omentum, and the gastro-
splenic omentum.
The Lesser, or Gastro-hepatic Omentum, is the duplicature which extends
between the transverse fissure of the liver, and the lesser curvature of the
stomach. It is extremely thin, and consists, as before said, of two layers of
peritoneum. At the left border, its two layers pass on to the end of the oesopha-
gus; but, at the right border, where it is free, they are continuous, and form a
free rounded margin, which contains between its layers the hepatic artery, the
ductus communis choledocus, the portal vein, lymphatics, and hepatic plexus
of nerves; all these structures being enclosed in loose areolar tissue, called
Glisson's capsule.
The Great Omentum {gastro- colic) is the largest peritoneal fold. It consists
of four layers of peritoneum, two of which descend from the stomach, one from
its anterior, the other from its posterior surface; these, uniting at its lower
border, descend in front of the small intestines, as low down as the pelvis; and
the same two ascend again as far as the transverse colon, where they separate and
enclose that part of the intestine. These separate layers may be easily demon-
strated in the young subject, but, in the adult, they are more or less inseparably
blended. The left border of the great omentum is continuous with the gastro-
splenic omentum: its right border extends as far only as the duodenum. The
great omentum is usually thin, presents a cribriform appearance, and always
contains some adipose tissue, which, in fat subjects, accumulates in considerable
quantity. Its use appears to be to protect the intestines from cold, and to facili-
tate their movement upon each other during their vermicular action.
The Gastro- Splenic Omentum is the fold which connects the concave surface
of the spleen to the cul-de-sac of the stomach, being continuous by its lower
border with the great omentum. It contains the splenic vessels and vasa brevia.
The Mesenteries are, the mesentery proper, the me&o-csecum, the ascending,
transverse, and descending meso-colon, and the meso-rectum.
The Mesentery (fxecrov, evrepov), so called from being connected to the middle
of the cylinder of the small intestine, is the broad fold of peritoneum which
connects the convolutions of the jejunum and ileum with the posterior wall of the
abdomen. Its root, the part connected with the vertebral column, is narrow,
about six inches in length, and directed obliquely from the left side of the second
lumbar vertebra, to the right sacro-iliac symphysis. Its intestinal border is much
longer; and here its two layers separate, so as to enclose the intestine, and form
its peritoneal coat. Its breadth, between its vertebral and intestinal border, is
about four inches. Its upper border is continuous with the under surface of the
transverse meso-colon; its loiver border., with the peritoneum covering the caecum
6o2 ORGANS OF DIGESTION.
and ascending colon. It serves to retain the small intestines in their position,
and contains between its layers the mesenteric vessels and nerves, the lacteal
vessels, and mesenteric glands.
The Meso-Ccecum, when it exists, serves to connect the back part of the
caecum with the right iliac fossa; more frequently, the peritoneum passes merely
in front of this portion of the large intestine.
The Ascending Meso- Colon is the fold which connects the back part of the
ascending colon with the posterior wall of the abdomen.
The Descending Meso- Colon retains the descending colon in connection with
the posterior abdominal wall; more frequently, the peritoneum merely covers the
anterior surface and sides of these two portions of the intestine.
The Transverse Mesa-Colon is a broad fold, which connects the transverse
colon with the posterior wall of the abdomen. It is formed of the two ascending
layers of the great omentum, which, after separating to surround the transverse
colon, join behind it, and are continued backwards to the spine, where they
diverge in front of the duodenum, as already mentioned. This fold contains
between its layers the vessels which supply the transverse colon.
The Sigmoid Meso- Colon is the fold of peritoneum which retains the sigmoid
flexure in connection with the left iliac fossa.
The Meso-Rectum is the narrow fold which connects the upper part of the
rectum with the front of the sacrum. It contains the hemorrhoidal vessels.
The Appendices Epiploicce are small pouches of the peritoneum filled with
fat, and situated along the colon and upper part of the rectum. They are chiefly
appended to the transverse colon.
The Stomach.
The stomach is the principal organ of digestion. It is the most dilated part
of the alimentary canal, serving for the solution and reduction of the food, which
constitutes the process of chymification. It is situated in the left hypocondriac,
the epigastric, and part of the right hypocondriac regions. Its form is irregularly
conical, curved upon itself, and presenting a rounded base, turned to the left side.
It is placed immediately behind the anterior wall of the abdomen, above the
transverse colon, below the liver and Diaphragm. Its size varies considerably in
different subjects, and also according to its state of distension. When moderately
full, its transverse diameter is about twelve inches, its vertical diameter about
four. Its weight, according to Clendenning, is about four ounces and a half. It
presents for examination two extremities, two orifices, two borders, and two
surfaces.
Its left extremity is called the greater, or Splenic end. It is the largest part
of the stomach, and expands for two or three inches to the left of the point of
entrance of the oesophagus. This expansion is called the great cul-de-sac, or
fundus. It lies beneath the ribs, in contact with the spleen, to which it is
connected by the gastro-splenic omentum.
The lesser, or pyloric end, is much smaller than the preceding, and situated on a
plane anterior and inferior to it. It lies in contact with the wall of the abdomen,
the under surface of the liver, and the neck of the gall-bladder.
The oasophageal, or cardiac orifice, communicates with the oesophagus: it is
the highest part of the stomach, and somewhat funnel-shaped in form.
The pyloric orifice communicates with the duodenum, the aperture being
guarded by a valve.
The lesser curvature extends between the oesophageal and cardiac orifices,
along the upper border of the organ, and is connected to the under surface of the
liver by the lesser omentum.
The greater curvature extends between the same points, along the lower
border, and gives attachment to the great omentum. The surfaces of the organ
are limited by these two curvatures.
STOMACH.
603
The anterior surface is directed upwards and forwards, and is in relation with
the Diaphragm, the under surface of the left lobe of the liver, and, in the
epigastric region, with the abdominal parietes.
310. — The Mucous Membrane of the Stomach and Duodenum, with the Bile Ducts.
Cys-tle
The posterior surface is directed downwards and backwards, and is in relation
with the pancreas and great vessels of the abdomen, the crura of the Diaphragm,
and the solar plexus.
The stomach is held in position by the lesser omentum, which extends from
the transverse fissure of the liver to its lesser curvature, and by a fold of peri-
toneum, which passes from the Diaphragm on to the oesophageal end of the
stomach, the gastro-phrenic ligament; this constitutes the most fixed point of the
stomach, whilst the pyloric end and greater curvature are the most moveable
parts ; hence, when this organ becomes greatly distended, the greater curvature is
directed forwards, whilst the anterior and posterior surfaces are directed, the
former upwards, and the latter downwards.
Alterations in Position. There is no organ in the body the position and connexions of
which present such frequent alterations as the stomach. During inspiration it is displaced
downwards by the descent of the Diaphragm, and elevated by the pressure of the abdo-
minal muscles during expiration. Its position to the surrounding viscera is also changed,
according to the empty or distended state of the organ. When empty, it occupies only a
small part of the left hypochondriac region, the spleen lying behind it ; the left lobe of
the liver covers it in front, and the under surface of the heart rests upon it above, and in
front, being separated from it by the left lobe of the liver and pericardium. Hence it is,
that, in gastralgia, the pain is generally referred to the heart, and is often accompanied by
palpitation and intermission of the pulse. When the stomach is distended the Diaphragm
is forced upwards, contracting the cavity of the chest ; hence the dyspnoea complained of
from inspiration being impeded. The heart is also displaced upwards ; hence the oppres-
6o4
ORGANS OF DIGESTION.
sion in this region, and the palpitation experienced in extreme distension of the stomach.
Pressure from without, as in the pernicious practice of tight lacing, pushes the stomach
down towards the pelvis. In disease, also, the position and connexions of the organ may-
be greatly changed, from the accumulation of fluid in the chest or abdomen, or when the
size of any of the surrounding viscera undergoes alteration.
On looking into the pyloric end of the stomach, the mucous membrane is found
projecting inwards in the form of a circular fold, the pylorus, leaving a narrow
circular aperture, about half an inch in diameter, by which the stomach communi-
cates with the duodenum.
The pylorus is formed by a reduplication of the mucous membrane of the
stomach, containing its circular muscular fibres, which are here aggregated into a
thick circular ring, the longitudinal fibres and serous membrane being continued
over the fold without assisting in its formation. The aperture is occasionally
oval. Sometimes the circular fold is replaced by ttvo crescentic folds, placed one
above and the other below the pyloric orifice; and, more rarely, there is only one
crescentic fold.
Structure. The stomach consists of four coats, a serous, a musculai", a cellular,
and a mucous coat, together with vessels and nerves.
The serous coat is derived from the peritoneum, and covers the entire surface
of the organ, excepting along the greater and lesser curvatures, at the points of
attachment of the greater and lesser omenta; here the two layers of peritoneum
leave a small triangular space, along which the nutrient vessels and nerves
The WMScular coat (fig. 311) is situated immediately beneath the serous cover-
ing. It consists of three sets of fibres, longitudinal, circular, and oblique.
311. — The Muscular Coat of the Stomach. The Innermost LaytT is not seen.
The longitudinal fibres are placed most externally; they are continuous with
the longitudinal fibres of the oesophagus, radiating in a stellate manner from the
cardiac orifice. They are most distinct along the curvatures, especially the lesser,
but are very thinly distributed over the surfaces. At the pyloric end, they are
STRUCTURE OF STOMACH.
605
more thickly distributed, and continuous with the longitudinal fibres of the small
intestine.
The circular fibres form a uniform layer over the whole extent of the
stomach, beneath the longitudinal fibres. At the pylorus, they become thicker,
and are aggregated into a circular ring, which projects into the cavity, and forms,
with the fold of mucous membrane covering its surface, the pyloric valve.
The internal or oblique fibres are limited chiefiy to the great end of the
stomach, where they are disposed as a thick uniform layer, and from this point
they descend obliquely upon its anterior and posterior surfaces, upon which they
become lost.
The cellular coat consists of a loose filamentous areolar tissue, connecting the
mucous and muscular layers. It is sometimes called the submucous coat. It
supports the blood-vessels previous to their distribution to the mucous membrane;
hence it is sometimes called the vascular coat.
The mucous membrane is thick; its surface smooth, soft, and of a pulpy con-
sistence. During infancy, and immediately after death, it is of a pinkish tinge;
but in adult life and in old age it becomes of a pale straw or ash-grey colour. It
is thin at the cardiac extremity, but thicker towards the pylorus. During the
contracted state of the organ it is thrown into plaits or rugae, which, for the most
part, have a longitudinal direction, and are most numerous towards the lesser end
of the stomach and along the greater curvature. These folds are entirely obliter-
ated when the organ becomes distended.
Structure of the mucous membrane (fig. 312). The entire surface of the mucous
3 1 2. — Minute Anatomy of Mucous Membrane of Stomach.
Alveoli ^_piiheJi^
SlbutAs of Tic6i/,U
Orifice of Tu2e
EpitheliaZ particles
membrane is covered with small shallow depressions or alveoli, of a polygonal or
hexagonal form, which vary from i-iooth to i- 200th of an inch in diameter. At
the bottom of the alveoli, as well as in the intervals between them, are seen the
orifices of minute tubes, the gastric follicles, which are situated perpendicularly
side by side, over the entire surface of the mucous membrane. They are short,
and simply tubular in character towards the cardia, but at the pyloric end they
are longer, more convoluted, and terminate in dilated saccular extremities, or
subdivide into from two to six tubular branches. The gastric follicles are
composed of a homogeneous basement membrane, lined upon its free surface by a
layer of cells, which differ in their character in difierent parts of the stomach.
Towards the pylorus, these tubes are lined throughout with columnar epithelium.
They are termed the mucous glands, and are supposed to secrete the gastric
mucus. In other parts of the organ, the deep part of each tube is filled with
nuclei, and a mass of granules; above these are a mass of nucleated cells, the
upper fourth of the tube being lined by columnar epithelium. These are called
the peptic glands, the supposed agents in the secretion of the gastric juice.
Simple follicles are found in greater or less numbers over the entire surface of
6o6 OKGANS OF DIGESTION.
the mucous membrane; they are most numerous near the pyloric end of the
stomach, and especially distinct in early life. The epithelium lining the mucous
membrane of the stomach and its alveoli is of the columnar variety.
Vessels and Nerves. The arteries supplying the stomach are the gastric, pyloric
and right gastro-epiploic branches of the hepatic, the left gastro-epiploic and vasa
brevia from the splenic. They supply the muscular coat, ramify in the submucous
coat, and are finally distributed to the mucous membrane. The veins accompany
the arteries, and terminate in the splenic and superior mesenteric veins. The
lymphatics are numerous: they consist of a superficial and deep set, which pass
through the lymphatic glands found along the two curvatures of the organ.
The nerves are the terminal branches of the right and left pneumogastric, the
former being distributed upon the back, and the latter upon the front part of the
organ. Branches from the sympathetic also suj)ply the organ.
The Small Intestines.
The small intestine is that part of the alimentary canal in which the food is
mixed with the bile and pancreatic juice, and where the separation of the nutri-
tive principles of the food, the chyle, is effected: this constitutes chylification.
The small intestine is a convoluted tube, about twenty feet in length, which
gradually diminishes in size from its commencement to its termination. It is
contained in the central and lower parts of the abdominal and pelvic cavities,
surrounded above and at the sides by the large intestine, in relation in front with
the mesentery and abdominal parietes, and connected to the spine by a fold of
peritoneum, the mesentery. The small intestine is divisible into three portions;
the duodenum, jejunum, and ileum.
The Duodenum has received its name from being about equal in length to the
breadth of twelve fingers (eight or ten inches). ^It is the shortest, the widest,
and the most fixed part of the small intestine; it has no mesentery, and is only
partially covered by the peritoneum. Its course presents a remarkable curve,
somewhat like a horse-shoe in form; the convexity being directed towards the
right, and the concavity to the left, embracing the head of the pancreas. Com-
mencing at the pylorus, it ascends obliquely to the under surface of the liver; it
then descends in front of the right kidney, and passes nearly transversely across
the front of the second lumbar vertebra, terminating in the jejunum on the left
side of this bone. Hence the duodenum has been divided into three portions;
ascending, descending, and transverse.
The first, or ascending portion, about two inches in length, is free and move-
able, and completely invested by the peritoneum. It commences at the pylorus,
and passes obliquely upwards and backwards to the under surface of the liver.
It is in relation, above and in front, with the liver and neck of the gall-bladder;
behind, with the right border of the lesser omentum, the hepatic artery and duct,
and vena portge. This portion of the intestine is usually found stained with bile,
especially on its anterior surface.
The second, or descending portion, about three inches in length, is firmly fixed
by the peritoneum and pancreas. It passes from the neck of the gall-bladder
vertically downwards, in front of the right kidney, as far as the third lumbar
vertebra. It is covered by peritoneum only on its anterior surface. It is in
relation, by its anterior surface, with the right aTch of the colon and meso-colon;
by its posterior surface, it is connected to the front of the right kidney by loose
areolar tissue ; at its inner side is the head of the pancreas, and the common
choledic duct. The common bile and pancreatic ducts perforate this side of the
intestine obliquely, a little below its middle.
The third, or transverse portion, the longest and narrowest part of the duode-
num, passes across the front of the spine, ascending from the third to the second
lumbar vertebra, terminating in the jejuntun on the left side of the second lumbar
vertebra. In front, it is covered by the ascending and descending layers of the
transverse meso-colon, and crossed by the superior mesenteric vessels; behind, it
\
SMALL INTESTINES. 607
rests upon tlie aorta, the vena cava, and the crura of the diaphragm; above it, is
the lower border of the pancreas, the superior mesenteric vessels passing forwards
between the two.
The arteries supplying the duodenum are the pyloric and superior pancreatico-
duodenal branches of the hepatic, and the inferior pancreatico-duodenal branch of
the superior mesenteric.
The veins terminate in the gastro-duodenal and superior mesenteric.
Its nerves are derived from the solar plexus.
The Jejunum {jejunus, empty), so called from being usually found empty after
death, inclvides the upper two-fifths of the rest of the small intestine. It com-
mences at the duodenum on the left side of the second lumbar vertebra, and
terminates in the ileum; its convolutions being chiefly confined to the umbilical
and left iliac regions. The jejunum is wider, its coats thicker, more vascular,
and of a deeper colour than those of the ileum; but there is no characteristic
mark to distinguish the termination of the one, or the commencement of the
other.
The Ileum (elXeiv, to ttvist), so called from its numerous coils or convolu-
tions, includes the remaining three-fifths of the small intestine, occupying chiefly
the umbilical, hypogastric, right iliac, and occasionally the pelvic, regions, and ter-
minating in the right iliac fossa by opening into the inner side of the commence-
ment of the large intestine. The ileum is narrower, its coats thinner and less
vascular than those of the jejunum; a given length of it weighing less than the
same length of jejunum.
Structure. The wall of the small intestine is composed of four coats; serous,
muscular, cellular, and mucous.
The serous coat is derived from the peritoneum. The first, or ascending por-
tion of the duodenum, is completely surrounded by this membrane; the second, or
descending portion, is covered by it only in front; and the third, or transverse,
portion lies behind the ascending and descending layers of the transverse meso-
colon, by which it is covered in front. The remaining portion of the small
intestine is completely sui-rounded by the peritoneum, excepting along the attached
or mesenteric border of the intestine; here a space is left for the vessels and
nerves to pass to the intestine.
The muscular coat consists of two layers of fibres, an external or longitudinal,
and an internal or circular layer. The longitudinal fibres are thinly scattered
over the surface of the intestine, and are most distinct along its free border.
The circular fibres form a thick, uniform layer; they surround the cylinder of
the intestine in the greater part of its circumference, but do not form complete
rings. The muscular coat is thicker at the upper, than at the lower part of the
small intestine.
The cellular, or submucous coat, connects together the mucous and muscular
layers. It consists of a loose, filamentous, areolar tissue, which forms a nidus for
the subdivision of the nutrient vessels, previous to their distribution to the mucous
surface.
The mucous membrane is thick* and highly vascular at the upper part of the
small intestine, but somewhat paler and thinner below. It presents for examina-
tion the following constituents :
-r^ .^, T Simple follicles.
Epithelium. , ^ \ , , ,
-t^/ 1 , . , ( Duodenal glands.
Valvulse conniventes. ^t -. o t^ i i
-Y-[Y (jrlands. ■; Solitary glands.
( Agminate or Peyer's glands.
The Epithelium, covering the mucous membrane of the small intestines, is of
the columnar variety throughout.
The Valvulce Conniventes (valves of Kerkring) are reduplications or foldings
of the mucous membrane, containing no muscular fibres. They extend trans-
versely across the cylinder of the intestine for about one-half or three-fourths of
6o8
OEGANS OF DIGESTION.
313- — Two Villi magnified.
its circumference. The larger folds are about two inches in length, and two-
thirds of an inch wide at their broadest part; but the greater number are of
smaller size. The larger and smaller folds alternate with each other. They are
not found at the commencement of the duodenum, but begin to appear about one
or two inches beyond the pylorus. In the lower part of the descending portion,
below the point where the common choledic and pancreatic ducts enter the intes-
tine; they are very large and closely approximated. In the transverse portion of
the duodenum and upper half of the jejunum, they are large and numerous; and
from this point, as far as the middle of the ileum, where they terminate, they
diminish considerably in size. In the lower half of the ileum, the mucous lining
is without folds; hence the comparative thinness of this portion of the intestine,
as compared with the duodenum and jejunum. The valvulae conniventes retard
the passage of the food along the intestines, and afford a more extensive surface
for absorption.
The Villi are minute, highly vascular,
projecting processes, covering the mucous
membrane of the small intestine through-
out its whole extent, and giving to its
entire surface a beautiful velvety appear-
ance. In shape, some are triangular and
laminated, others conical or cylindrical,
with clubbed, or filiform extremities. They
are largest and most numerous in the
duodenum and jejunum, and become fewer
and smaller in the ileum. Krause estimates
their number in the upper part of the
small intestine, at from fifty to ninety in a
square line; and in the lower part, from
forty to seventy; the total number for the
whole length of the intestine being four
millions.
In structure each villus consists of a network of blood and lacteal vessels, with
granular corpuscles and fat globules in their interstices, enclosed in a thin pro-
longation from the mucous surface, covered by columnar epithelium, which is
arranged perpendicular to the surface. The mode of origin of the lacteals within
the villi is unknown.
The Simple Follicles, or crypts of Lieberklihn, are found in considerable
numbers over every part of the mucous membrane of the small intestine. They
consist of minute csecal pouches of the mucous membrane, arranged perpendicu-
larly to the surface, upon which they open by small circular apertures. Their
walls are thin, and lined with columnar epithelium.
The Duodenal, or Brunner's glands, are limited to the duodenum and com-
mencement of the jejunum (Huschke). They are small, flattened, granular bodies,
imbedded in the submucous areolar tissue, and open upon the surface of the
mucous membrane by minute excretory ducts. They are most numerous near
the pylorus. In structure, they are analogous to the salivary glands and
pancreas.
The Solitary Glands {glandulce solitaricB), are found scattered throughout the
mucous membrane of the small intestine, but are most nimierous in the lower
part of the ileum. They are small, round, Avhitish, prominent bodies, about the
size of a millet-seed, consisting of a closed saccular cavity, having no excretory
duct, and containing an opaque Avhite secretion. Their free surface is covered
with villi, and around them is scattered irregularly the orifices of the follicles
of Lieberkiihn. Their use is not known.
The Aggregate, or Peyei-'s glands, are largest and most numerous in the ileum.
In the lower part of the jejunum they are small, of a circular form, and few
in number, and they are occasionally seen in the duodenum. They consist of
LARGE INTESTINE.
609
314- — Patch of Peyer's Glands.
From tlie lower part of the Ileum.
-A portion of the above magnified.
Orifices of LieberTcuhn's Follicles.
circular or oval patches, from twenty to thirty in number, and varying in length
from half an inch to four inches. They are placed lengthwise in the intestine,
covering the portion of the tube most
distant from the attachment of the mesen-
tery. Each patch is formed of a group of
small, round, whitish vesicles, covered with
mucous membrane. Each vesicle consists
of a moderately thick external capsule,
having no excretoiy duct, and containing
an opaque white secretion. Each is sur-
rounded by a zone, or wreath of simple
follicles, and the interspaces between them
covered with villi. These vesicles are
usually closed; but it is supposed they open
at intervals to discharge the secretion con-
tained within them. The mucous and sub-
mucous coats of the intestine are intimately
adherent, and highly vascular, opposite the
Peyerian glands. Their use is not known.
The Large Intestine.
The large intestine extends from the
tei'mination of the ileum to the anus. It
is about five feet in length; being one-fifth 315-
of the whole extent of the intestinal canal.
It is largest at its commencement at the
caecum, and gradually diminishes as far as
the rectum, where there is a dilatation of
considerable size, just above the anus. It
differs from the small intestine in its greater
size, its more fixed position, and its saccu-
lated form. The large intestine, in its
course, describes an arch, which surrounds
the convolutions of the small intestine. It
commences in the right iliac fossa, in a
dilatation of considerable size, the caecum.
It ascends through the right lumbar and
hypochondriac regions, to the under surface
of the liver; passes transversely across the
abdomen, on the confines of the epigastric
and umbilical regions, to the left hypochondriac region; descends through the left
lumbar region to the left iliac fossa, where it becomes convoluted, and forms the
sigmoid flexure; finally, it enters the pelvis, and descends along its posterior
surface to the anus. The large intestine is divided into the csecum, colon, and
rectum.
The Ccecum {ccecus, blind), is the large blind pouch, or cul-de-sac, extending
downwards from the commencement of the large intestine. It is the most dilated
part of this tube, measuring about two and a half inches, both in its vertical and
transverse diameters. It is situated in the right iliac fossa, immediately behind
the anterior abdominal wall, being retained in its place by the peritoneum, which
passes over its anterior surface and sides; its posterior surface being connected by
loose areolar tissue with the iliac fascia. Occasionally, it is almost completely
surrounded by peritoneum, which forms a distinct fold, the meso-ctecum, by which
it is held in connection with the iliac fossa. This fold allows the caecum con-
siderable freedom of movement. Attached to its lower and back part, is the
appendix vermiformis, a long, narrow, worm-sliaped tube, the rudiment of the
lengthened caecum found in all the mammalia, except the ourang-outang and
R R
6io
ORGANS OF DIGESTION.
wombat. The appendix vai-ies from three to six inches in length, its average
diameter being about equal to that of a goose-quill. It is usually directed
upwards and inwards behind the CEecum, coiled upon itself, and terminates
316.-
-The Caecum and Colon laid open to shew the
Ilio-Csecal Valve.
in a blunt point, being retained in its position by a fold of peritoneum, which
sometimes forms a mesentery for it. Its canal is small, and communicates with
the caecum by an orifice which is sometimes guarded with an incomplete valve.
Its coats are thick, and its mucous lining furnished with a large number of
solitary glands.
Ilio-CcBcal Valve. The lower end of the ileum terminates at the inner and
back part of the large intestine, opposite the junction of the caecum with the
colon. At this point, the mucous membrane forms two valvular folds, which pro-
ject into the large intestine, and are separated from each other by a narrow
elongate aperture. This is the ilio-cascal valve {valvula Bauhini). Each fold is
semilunar in form, and projects vertically inwards, the upper one being attached
by its convex border to the point of junction of the ileum with the colon; the
lower segment, the larger, being connected at the point of junction of the ileum
witli the caecum. Their concave margins are free, project into the intestine,
separated from one another by a narrow elongated aperture, which has a trans-
verse direction. At each end of this aperture, the two segments of the valve
coalesce, and are continued, as a narrow membranous ridge, around the canal of
the intestine for a short distance, forming the. fra3na, or retinacula of the valve.
The left end of this aperture, is rounded: the right end is narrow and pointed.
Each segment of the valve is formed of a reduplication of the mucous mem-
brane, and of the circular muscular fibres of the intestine, the longitudinal fibres
and peritoneum being continued uninterruptedly across from one intestine to the
other. When these are divided or removed, the ileum may be drawn outwards,
and all traces of the valve will be lost, the ileum appearing to open into the large
intestine by a funnel-shaped orifice of large size.
The surface of each segment of the valve directed towards the ileum is covered
with villi, and presents the characteristic structure of the mucous membrane of
LARGE INTESTINE. 6ii
the small intestine; whilst that turned towards the large intestine is destitute of
villi, and marked with the orifices of the numerous tubuli peculiar to this mem-
brane. These differences in structure continue as far as the free margin of the
valve.
When the caecum is distended, the margins of the opening are approximated, so
as to prevent any reflux into the ileum.
The Colon is divided into four parts, the ascending, transverse, descending, and
the sigmoid flexure.
The ascending colon is smaller than the ccecum. It passes upwards from the
right iliac fossa, to the under surface of the liver, on the right of the gall-
bladder, where it bends abruptly inwards to the left, forming the hepatic flexure.
It is retained in position to the wall of the abdomen by the peritoneum, which
covers its anterior surface and sides, its posterior surface being connected by
loose areolar tissue with the Quadratus lumborum and right kidney ; sometimes the
peritoneum almost completely invests it, and forms a distinct but narrow meso-
colon. It is in relation, in front, with the convolutions of the ileum and the
abdominal parietes; behind, it lies on the Quadratus lumborum muscle, and right
kidney.
The transverse colon, the longest part of the large intestine, passes transversely
from right to left across the abdomen, opposite the confines of the epigastric and
umbilical zones, into the left hypochondi'iac region, where it curves downwards
beneath the lower end of the spleen, forming its splenic flexure. In its course it
describes an arch, the concavity of which is directed backwards towards the ver-
tebral column; hence the name, transverse arch of the colon. This is the most
moveable part of the colon, being completely invested by peritoneum and connected
to the spine behind by a large and wide duplicature of this membrane, the trans-
verse meso-colon. It is in relation, by its upper surface, with the liver and gall-
bladder, the great curvature of the stomach, and the lower end of the spleen; by
its under surface, with the small intestines; by its anterior surface, with the ante-
rior layers of the great omentum and the abdominal parietes; by its posterior
surface, with the transverse meso-colon.
The descending colon passes almost vertically downwards through the left
hypochondriac and lumbar regions to the left iliac fossa, where it terminates in
the sigmoid flexure. It is retained in position by the peritoneum, which covers
its anterior surface and sides, its posterior surface being connected by areolar
tissue with the left crus of the Diaphragm, the left kidney, and the Quadratus
lumborum. It is smaller in calibre and more deeply placed than the ascending
colon.
The sigmoid Jlexure is the narrowest part of the colon; it is situated in the left
iliac fossa, commencing at the termination of the descending colon, at the margin
of the crest of the ilium, and terminating in the rectum, opposite the left sacro-
iliac symphysis. It curves in the first place upwards, and then descends verti-
cally, and to one or the other side like the letter^ hence its name; and is retained
in its place by a loose fold of peritoneum, the iliac meso-colon. It is in relation,
in front, with the small intestines and abdominal parietes; behind, with the iliac
fossa.
The Rectum is the terminal part of the large intestine, and extends from the
sigmoid flexure to the anus; it varies in length from six to eight inches, and has
received its name from being somewhat less flexuous than any other part of the
intestinal canal. It commences opposite the left sacro-iliac symphysis, passes
obliquely downwards from left to right to the middle of the sacrum, forming a
gentle curve to the right side. Regaining the middle line, it descends in front of
the lower part of the sacrum and coccyx, and near the extremity of the latter
bone inclines backwards to terminate at the anus, being curved both in the lateral
and antero-posterior directions. The rectum is, therefore, not straight, the upper
part being directed obliquely from the left side .to the median line, the middle
RR 2
6i2 ORGANS OF DIGESTION.
portion being curved in the direction of the hollow of the sacrum and coccyx, the
lower portion presenting a short curve in the opposite direction. The rectum is
cylindrical, not sacculated like the rest of the large intestine ; it is narrower at its
upper part than the sigmoid flexure, gradually increases in size as it descends,
and immediately above the anus presents a considerable dilatation, capable of
acquiring an enormous size. The rectum is divided into three portions, upper,
middle, and lower.
The upper portion, which includes about half the length of the tube, extends
obliquely from the left sacro-iliac symphysis to the centre of the third piece of the
sacrum. It is almost completely surrounded by peritoneum, and connected to the
sacrum behind by a duplicature of this membrane, the meso-rectum. It is in
relation behind with the Pyriformis muscle, the sacral plexus of nerves, and the
branches of the internal iliac artery of the left side, which separate it from the
sacrum and sacro-iliac symphysis; in front, it is sep&,rated, in the male, from the
posterior surface of the bladder; in the female, from the posterior surface of
the uterus and its appendages, by some convolutions of the small intestine.
The middle portion of the rectum is about three inches in length, and extends
as far as the tip of the coccyx. It is closely connected to the concavity of the
sacrum, and covered by peritoneum only on the upper part of its anterior surface.
It is in relation, in front, with the triangular portion of the base of the bladder,
the vesiculie seminales, and vasa deferentia; more anteriorly, with the under sur-
face of the prostate. In the female, it is adherent to the posterior wall of the
vagina.
The third portion is about an inch in length ; it curves backwards at the fore
part of the prostate gland, and terminates at the anus. This portion of the intes-
tine receives no peritoneal covering. It is invested by the Internal sphincter,
supported by the Levatores ani muscles, and surrounded at its termination by the
External sphincter. In the male, it is separated from the membranous portion
and bulb of the urethra by a triangular space; and, in the female, a similar space
intervenes between it and the vagina. This space forms by its base the peri-
nsEum.
Structure. The large intestine has four coats, serous, muscular, cellular, and
mucous.
The serous coat \^ derived from the peritoneum, and invests the different por-
tions of the large intestine to a variable extent. The csecum is covered only on
its anterior surface and sides; more rarely it receives a complete investment, and
is held in its position by a duplicature, the meso-csecum. The ascending and
descending colon are usually covered only in front. The transverse colon is
completely invested, excepting at the points corresponding to the attachment of
the great omentum and transverse meso-colon. The sigmoid flexure is also com-
pletely surrounded, excepting at the point corresponding to the attachment of the
iliac meso-colon. The upper part of the rectum is completely invested by the
peritoneum; the upper portion is covered only on its anterior surface; and the
lower third is entirely devoid of any serous investment.
The muscular coat consists of an external longitudinal and an internal circular
layer of muscular fibres.
The longitudinal fibres are found as a unifoi'm layer over the whole surface of
the large intestine. In the csecum and colon, they are especially collected into
three flat longitudinal bands, each being about half an inch in width. These
bands commence at the attachment of the appendix vermiformis to the cascum:
one, the posterior, is placed along the attached border of the intestine; the ante-
rior band, the largest, becomes inferior along the arch of the colon, where it cor-
responds to the attachment of the great omentum, but is in front in the ascending
and descending colon and sigmoid flexure; the third, or lateral band, is found on
the inner side of the ascending and descending colon, and on the under border of
the transverse colon. These bands are nearly one-half shorter than the other
parts of the intestine, and serve to produce those sacculi characteristic of the
STRUCTUEE OF LARGE INTESTINE.
613
caecum and colon; accordingly, when they are dissected off, the tube can be
lengthened, and its sacculated character becomes lost. In the sigmoid flexure,
the longitudinal fibres become more scattered, and upon its lower part, as well as
around the rectum, they spread out and form a thick uniform layer.
The circular fibres form a thin layer over the cajcum and colon, being espe-
cially accumulated in the intervals between the sacculi; in the rectum, they form
a thick layer, especially at its lower end, where they become numerous, and form
the Internal sphincter.
The cellular coat connects closely together the muscular and mucous layers.
The mucous membrane, in the ctecum and colon, is pale, and of a greyish
or pale yellow colour. It is quite smooth, destitute of villi, and raised into
numerous crescentic folds, which correspond to the intervals between the sacculi.
In the rectum, it is thicker, of a darker colour, more vascular, and connected
loosely to the muscular coat, as in the oesophagus. In its contracted state, the
lower part of the rectum is thrown into a number of longitudinal folds, similar to
those in the oesophagus, the larger of which have been called by Morgagni, the
columns of the rectum. Besides these, the mucous membrane forms three pro-
minent valvular folds, specially described by Mr. Houston. They are all directed
obliquely; one is situated near the commencement of the rectum, on the right
side; another extends inwards from the side of the tube opposite the middle of
the sacrum; and the third projects backwards from the fore part of the rectum,
opposite the prostate gland; these folds become effaced when the canal is dis-
tended. The mucous membrane of the large intestine presents for examination :
epithelium, simple follicles, and solitary glands.
317. — Minute Structure of Large Intestine.
Aptrtiires ofTutuli
Aperture oji
jSoUfar^ FoTlic-le-
jp7>ee Surface
The epithelium is of the columnar kind.
The simple follicles are minute tubular prolongations of the mucous membrane,
arranged perpendicularly, side by side, over its entire surface; they are longer,
more numerous, and placed in much closer apposition than those of the small
intestine; and they open by minute rounded orifices upon the surface, giving it a
cribriform appearance.
The solitary glands in the large intestine, are most abundant in the ca;cum
and appendix vermiformis, being irregularly scattered over the rest of the intes-
tine; they are small, prominent, circular bodies, of a whitish colour, perforated
upon the central part of their free surface by a minute orifice.
The Livek.
The liver is a glandular organ of large size, intended for the secretion of the
bile. It is situated in the right hypochondriac region, and extends across the
epigastrium into the left hypochondrium. It is. the largest gland in the body,
weighing from three to four pounds (from fifty to sixty ounces avoirdupois)
It
6 14 ORGANS OF DIGESTION.
measures, in its transverse diameter, from ten to twelve inches; from six to seven
in its antero-posterior ; and is about three inches thick at tlie back part of the
right lobe, wliich is the thickest part.
Its upper surface is convex, directed upwards and forwards, smooth, covered
by peritoneum, and is in relation with the under surface of the Diaphragm; and
below, to a small extent, with the abdominal parietes. This surface is divided
into two unequal lobes, the right and left, by a fold of peritoneum, the suspensory
or broad ligament.
Its under surface is concave, directed downwards and backwards, and in rela-
tion with the stomach and duodenum, the hepatic flexure of the colon, and the
right kidney and supra-renal capsule. This surface is divided, by a longitudinal
fissure, into a right and left lobe.
The posterior border is rounded and broad, and connected to the Diaphragm by
the coronary ligament; it is in relation with the aorta, the vena cava, and the
crura of the Diaphragm.
The anterior border is thin and sharp, and marked, opposite the attachment of
the broad ligament, by a deep notch. In adult males, this border usually corre-
sponds with the margin of the ribs; but in women and children, it projects usually
below this point.
The right extremity of the liver is thick and rounded ; whilst the left is thin
and flattened.
Changes of Position. The student should make himself acquainted with the different
circumstances under which the liver changes its position, as they are of importance as a
guide in determining the existence of enlargement, or other disease of that organ.
Its position varies according to the posture of the body ; in the upright and sitting
postures, its lower border may be felt beneath the edges of the ribs ; ia the recumbent
posture, it usually recedes beneath the ribs.
Its position varies with the ascent or descent of the Diaphragm. Iv. a deep inspiration,
the liver descends below the ribs ; in expiration, it is raised to its ordinary level. Again,
in emphysema, where the lungs are distended, and the Diaphragm descends very low, the
liver is pushed down ; but in some other diseases, as phthisis, where the Diaphragm is
much arched, the liver rises very high up.
Pressure from without, as in tight lacing, by compressing the lower part of the chest,
displaces the liver considerably, its anterior edge often extending as low as the crest of
the ilium ; and its convex surface is often, at the same time, deeply indented from pressure
of the ribs.
Its position varies greatly, according to the greater or less distension of the sto-
mach and intestines. When the intestines are empty, the hver descends in the abdomen ;
but when they are distended, it is pushed upwards. Its I'elations with surrounding organs
may also be changed by the growth of tumours, or from collections of fluid in the thoracic
or abdominal cavities.
Ligaments. The ligaments of the liver (fig. 318) are five in number: four
being formed of folds of peritoneum; the fifth, the ligamentum feres, is a round,
fibrous cord, resulting from the obliteration of the umbilical vein. The ligaments
are the longitudinal, two lateral, coronary, and round.
The Longitudinal Ligament (broad, falciform, or suspensory ligament) is a
broad and thin antero-posterior peritoneal fold, falciform in shape, its base being
directed forwards, its apex backwards. It is attached by one margin to the
under surface of the Diaphragm, and the posterior surface of the sheath of the
right Rectus muscle as low down as the umbilicus; by its hepatic margin, it
extends from the notch on the anterior margin of the liver, as far back as its
posterior border. It consists of two layers of peritoneum closely united together.
Its anterior free margin contains between its layers the round ligament.
The Lateral Ligaments, two in number, right and left, are triangular in shape.
They are formed of two layers of peritoneum united, and extend from the sides
of the Diaphragm to the adjacent margins of the posterior border of the liver.
The left is the longer of the two, and lies in front of the oesophageal opening in
the Diaphragm; the right lies in front of the inferior vena cava.
The Coronary Ligament connects the posterior border of the liver to the
LIVER.
615
Diaphragm. It is formed by the reflection of the peritoneum from the Diaphragm
on to the upper and lower margins of the posterior border of the organ. The
318. — The Liver. Upper Surface.
coronary ligament consists of two layers, which are continuous on each side with
the lateral ligaments; and in front, with the longitudinal ligament. Between the
layers, a large oval interspace is left uncovered by peritoneum, and connected to
the Diaphragm by firm areolar tissue. This space is subdivided, near its left
extremity, into two parts by a dsep notch (sometimes a canal), which lodges the
inferior vena cava, and into which open the hepatic veins.
The Round Ligament is a fibrous cord, resulting from the obliteration of the
umbilical vein. It ascends from the vimbilicus in the anterior free margin of the
longitudinal ligament, to the notch in the anterior border of the liver, from which
it may be traced along the longitudinal fissure on the under surface of the liver,
as far back as the inferior vena cava.
Fissures. Five fissures are seen upon the under surface of the liver, which
serve to divide it into five lobes. They are the longitudinal fissure, the fissure of
the ductus venosus, the transverse fissure, the fissure for the gall-bladder, and the
fissure for the vena cava.
The Longitudinal Fissure is a deep groove, which extends from the notch on
the anterior margin of the liver, to the posterior border of the organ. It sepa-
rates the right and left lobes; the transverse fissure joins it, at right angles, about
one-third from its posterior extremity, and divides it into two parts. The ante-
rior half is called the umbilical fissure : it is deeper than the posterior pai't, and
lodges the umbilical vein in the foetus, or its fibrous cord (the round ligament) in
the adult. This fissure is often partially bridged over by a prolongation of the
hepatic substance, the pons hepatis.
The Fissure of the Ductus Venosus is the back part of the longitudinal
fissure; it is shorter and shallower than the anterior portion. It lodges in the
foetus the ductus venosus, and in the adult a slender fibrous cord, the obliterated
remains of that vessel.
The Transverse, or Portal Fissure, is a short but deep fissure, about two
inches in length, extending transversely across the under surface of the right
lobe, nearer to its posterior than its anterior border. It joins, nearly at right
angles, with the longitudinal fissure. By the older anatomists, this fissure was
considered the gateway {porta) of the liver; hence the large vein which enters
6i6
ORGANS OF DIGESTION.
at this point was called the portal vein. Besides this vein, the fissure transmits
the hepatic artery and nerves, and the hepatic duct and lymphatics. At their
319. — The Liver. Under Surface.
entrance into the fissure, the hepatic duct lies to the right, the hepatic artery to
the left, and most posteriorly the portal vein.
The Fissure for the Gall-bladder {fossa cystis fellece) is n. shallow, oblong
fossa, placed on the under surface of the right lobe, parallel with the longitudinal
fissure. It extends from the anterior free margin of the liver, which is occa-
sionally notched for its reception, to near the right extremity of the transverse
fissure.
The Fissure for the Vena Cava is a short deep fissure, occasionally a com-
plete canal, which extends obliquely upwards from a little behind the right
extremity of the transverse fissure, to the posterior border of the organ, where it
joins the fissure for the ductus venosus. On slitting open the inferior vena cava
which is contained in it, a deep fossa is seen, at the bottom of which the hepatic
veins communicate with this vessel. This fissure is separated from the transverse
fissure by the lobus caudatus; and from the longitudinal fissure by the lobus
Spigelii.
Lobes. The lobes of the liver, like the ligaments and fissures, are also five in
number: the right lobe, the left lobe, the lobus quadratus, the lobus Spigelii, and
the lobus caudatus.
The right lobe is much larger than the left; the proportion between them being
as six to one. It occupies the right hypochondrium, and is separated from the left
lobe, on its upper surface, by the longitudinal ligament; on its under surface, by
the longitudinal fissui'e; and in front, by a deep notch. It is of a quadrilateral
form, its under surface being marked by three, fissures: the transverse fissure,
the fissure for the gall-bladder, and the fissure for the inferior vena cava; and by
two shallow impressions, one in front (irnpressio colica), for the hepatic flexure of
the colon; and one behind {irnpressio renalis), for the right kidney and supra-
renal capsule.
The left lobe is smaller and more flattened than the right. It is situated in the
epigastric and left hypochondriac regions, sometimes extending as far as the upper
border of the spleen. It upper surface is convex; its under concave surface rests
upon the front of the stomach; and its posterior border is in relation with the
cardiac orifice of the stomach.
STRUCTURE OF LIVER. 617
The Lobus Quadratus, or square lobe, is situated on the under surface of the
right lobe, bounded in front by the free margin of the liver; behind, by the trans-
verse fissure; on the right, by the fissure for the gall-bladder; and, on the left, by
the umbilical fissure.
The Lobus Spigelii projects from the back part of the under surface of the
right lobe. It is bounded, in front, by the transverse fissure; on the right, by
the fissure for the vena cava; and, on the left, by the fissure for the ductus
venosus.
The Lobus Caudatus, or tailed lobe, is a small elevation of the hepatic sub-
stance, extending obliquely outwards, from the base of the lobus Spigelii, to the
under surface of the right lobe. It separates the right extremity of the trans-
verse fissure from the commencement of the fissure for the inferior cava.
Vessels. The vessels connected with the liver are also five in number: they
are the hepatic artery, the portal vein, the hepatic vein, the hepatic duct, and
lymphatics.
The Hepatic Artery, Portal Vein, and Hepatic Duct, accompanied by numerous
lymphatic vessels and nerves, ascend to the transverse fissure, between the layers
of the gastro-hepatic omentum; the hepatic duct lying to the right, the hepatic
artery to the left, and the portal vein behind and between the other two. They
are enveloped in a loose areolar tissue, the capsule of Glisson, which accompanies
the vessels in their course through the portal canals, which are hollowed out of
the interior of the organ.
The Hepatic Veins convey the blood from the liver. They commence at the
circumference of the organ, and proceed towards the deep fossa in its posterior
bordei', where they tei'minate by two large, and several smaller branches, in the
inferior vena cava.
The hepatic veins have no cellular investment; consequently their parietes are
adherent to the walls of the canals through which they run: so that, on a section
of the organ, these veins remain widely open and solitary, and may be easily
distinguished from the branches of the portal vein, which are more or less col-
lapsed, and always accompanied by an artery and duct.
The Lymphatics are large and numerous, consisting of a deep and superficial
set. They have been already described.
Nerves. The nerves of the liver are derived from the hepatic plexus of the
sympathetic, from the pneumogastric nerves, especially the left, and from the
right phrenic.
Structure. The substance of the liver is composed of lobules, held together by
an extremely fine areolar tissue, of the ramifications of the portal vein, hepatic
duct, hepatic artery, hepatic veins, lymphatics, and nerves; the whole being
invested by a fibrous and a serous coat.
The serous coat is derived from the peritoneum, and invests the entire surface
of the organ, excepting at the point corresponding to the attachment of its
various ligaments, and at the bottom of the different fissures, where it is deficient.
It is intimately adherent to the fibrous coat.
The fibrous coat lies beneath the serous investment, and covers the entire
surface of the organ. It is difficult of demonstration, excepting where the serous
coat is deficient. At the transverse fissure, it is continuous with the capsule of
Glisson; and, on the surface of the organ, with the areolar tissue separating the
lobules.
The Lobules form the chief mass of the hepatic substance: they may be seen
either on the surface of the organ, or by making a section through the gland.
They are small granular bodies, about the size of a millet-seed, measuring from
one-twentieth to one-tenth of an inch in diameter. When divided longitudinally,
they have a foliated margin, and, if transversely, a polygonal outline. The bases
of the lobules are clustered round the smallest branches (sub-lobular) of the
hepatic veins, to which each is connected by means of a small branch, which
issues from the centre of each lobule (intra-lobular). The remaining part of the
6i8
ORGANS OF DIGESTION.
Fig. y.
H. Longitudinal section of an hepatic vein ; a. por-
tion of the canal, from which the vein has been
removed ; b. orifices of ultimate twigs of the vein
(sub-lobular), situated in the centre of the lobules.
After Kiernan.
surface of each lobule is imperfectly isolated from the surrounding lobules, by a
thin stratum of areolar tissue, or by the smaller vessels and ducts.
If one of the hepatic veins be laid
open, the bases of the lobules may be
seen through the thin wall of the vein,
on which they rest, arranged in the form
of a tessellated pavement, the centre of
each polygonal space presenting a mi-
nute aperture, the mouth of a sublobular
vein.
Each lobule is composed of a mass of
cells; of a plexus of biliary ducts; of a
venous plexus, formed by branches of
the portal vein; of a branch of an he-
patic vein (intralobular) ; of minute
arteries; and probably, of nerves and
lymphatics.
The hepatic cells form the chief mass
of the substance of a lobule, and lie in
the interspaces of the capillaiy plexus,
being probably contained in a tubular
network, which forms the origin of the
biliary ducts. The smallest branches of
the vena portas pass between the lobules,
around which they form a plexus, the
interlobular. Branches from this plexus
enter the lobules, and form a network in
its circumference. The radicles of the
portal vein communicate with those of
the hepatic vein, which occupy the centre of the lobule; and the latter converge
to form the intralobular vein, which issues from the base of the lobule, and joins
the hepatic vein. The portal vein carries the blood to the liver, from which the
bile is secreted; the hepatic vein carries from the liver the superfluous blood;
and the bile duct carries from the liver the bile secreted by the hepatic cells.
The Hepatic Cells form the chief mass of each lobule: they are of a more or
less spheroidal form; but may be rounded, flattened, or many-sided, from mutual
compression. They vary in size from the ^ q^^ q th to the s^Vo^^ ^^ ^^ inch in
diameter, and contain a distinct nucleus in the interior, or even sometimes two.
In the nucleus is a highly refracting nucleolus, with granules. The cell-contents
are viscid, and contain yellow particles, the colouring matter of the bile, and oil
globules. The cells adhere together by their surfaces, so as to form rows, which
radiate from the centre towards the circumference of the lobule. These cells are
the chief agents in the secretion of the bile; and, according to the extensive
researches of Dr. Beale, lie in a tubular network, which forms the origin of the
ducts.
Biliary Ducts. The precise mode of origin of the biliary ducts is uncertain.
Mr. Kiernan's original view, confirmed as it is by the researches of Dr. Beale,
shows that the ducts commence within the lobules, in a plexiform network (lobular
biliary plexus), in which the hepatic cells lie. The lobular ducts, on leaving the
lobules, form a plexus (interlobular) between the lobules; and the interlobular
branches unite into vaginal branches, which lie in the portal canals, with branches
of the portal vein and hepatic duct. The ducts finally join into two large trunks
which leave the liver at the transverse fissure.
The Portal Vein, on entering the liver at the transverse fissure, divides into
primary branches, which are contained in the portal canals, together Avith branches
of the hepatic artery and duct, and the nerves and lymphatics. In the larger
portal canals, the vessels are separated from the parietes, and joined to each other.
BILE DUCTS.
6ig
Fig. 32 1.
Longitudinal section of a small portal vein and
canal, after Kiernan. a. Portions of the canal,
from which the vein has heen removed ; b. side of
the portal vein in contact witli the canal ; c. the
side of the vein which is separated from the canal
by the hepatic artery and duct, with areolar tissue
(Glisson's capsiile); d. internal surface of the por-
tal vein, through which is seen the outlines of the
lobules and the openings of the interlobular veins;
/. vaginal veins of Kiernan; g. hepatic artery;
h. hepatic duct.
by a loose cellular web, the capsule of Glisson. The veins, as they lie in the portal
canals, give off vaginal branches, which form a plexus (vaginal plexus) in
Glisson's capsule. From this plexus,
and from the portal vein itself, small
branches are given oif, which pass be-
tween the lobules (interlobular veins);
these cover the entire surface of the
lobules, excepting their bases. The
lobular branches are derived from the
interlobular veins: they penetrate into
the lobule, and form a capillary plexus
within them. From this plexus the in-
tralobular vein arises.
The Hepatic artery enters the liver at
the transverse fissure, with the portal
vein and hepatic duct, and ramifies with
these vessels through the portal canals.
It gives off vaginal branches, which
ramify in the capsule of Glisson; and
other branches which are distributed to
the coats of the vena port^ and hepatic
duct. From the vaginal plexus, inter-
lobular branches are given off, which
ramify through the interlobular fissures,
a few branches being distributed to the
lobules. Kiernan supposes that the
branches of the hepatic artery terminate
in a capillary plexus which communicates
with the branches of the vena portae.
The Hepatic Veins commence in the interior of each lobule by a plexus, the
branches of which converge to form the intralobular vein.
The intralobular vein passes thi-ough
the centre of the lobule, and leaves it at Fig. 32 2.
its base to terminate in a sublobular ■
vein.
The sublobular veins unite with neigh-
bouring branches to form larger veins,
and they join to form the large hepa-
tic trunks, which terminate in the vena
cava.
Gall Bladder.
The gall bladder is the reservoir for
the bile; it is a conical or pear-shaped
membranous sac, lodged in a fossa on
the under surface of the right lobe of the
liver, and extending from near the right
extremity of the transverse fissure to the
anterior free margin of the organ. It is
about four inches in length, one inch in
breadth at its widest part, and holds
from eight to ten drachms. It is divided
into a fundus, body, and neck. The fundus, or broad extremity, is directed
downwards, forwards, and to the right, and occasionally projects from the anterior
border of the liver: the body and neck are directed upwards and backwards to the
left. The gall bladder is held in its position by the peritoneum, which, in the
A transverse section of a small portal cnnal and its
vessels, after Kiernan. 1 . Portal vein ; 2. inter-
lobular branches ; 3. branches of the vein, termed
by Mr. Kiernan, vaginal, also giving off inter-
lobular branches; 4. hepaiic duct; 5. hepatic
artery.
620 ORGANS OF DIGESTION.
majority of cases, passes over its under surface, but it occasionally invests it, and
is connected to the liver by a kind of mesentery.
Relations. The body of the gall bladder is in relation by its upper surface with
the liver, to which it is connected by areolar tissue and vessels; by its under sur-
face, Avith the first portion of the duodenum, occasionally the pyloric end of the
stomach, and the hepatic flexure of the colon. The fundus is completely invested
by peritoneum; it is in relation, in front, with the abdominal parietes, imme-
diately below the tenth costal cartilage; behind, with the transverse arch of the
colon. The neck is narrow, and curved upon itself like the italic letter f; at its
point of connection with the body and with the cystic duct, it presents a well
marked constriction.
When the gall bladder is distended with bile or calculi, the fundus may be felt through
the abdominal parietes, especially in an emaciated subject ; the relations of this sac will
also serve to explain the occasional occurrence of abdominal biliary fistulee, through which
biliary calculi may pass out, and of the passage of calculi from the gall bladder into the
stomach, duodenum, or colon, which occasionally hajppens.
Structure. The gall bladder consists of three coats, serous, fibrous and muscular,
and mucous.
The external or serous coat is derived from the peritoneum; it completely
invests the fundus, but covers the body and neck only on their under surface.
The middle or fibrous coat is a thin but strong fibrous layer, which forms the
framework of the sac, consisting of dense fibres which interlace in all directions.
Plain muscular fibres are also found in this coat, disposed chiefly in a longitudinal
direction, a few running transversely.
The internal or mucous coat is loosely connected with the flbrous layer. It is
generally tinged of a yellowish brown colour, and is everywhere elevated into
minute rugre, by the union of which numerous meshes are formed; the depressed
intervening spaces having a polygonal outline. The meshes are smaller at the
fundus and neck, being most developed about the centre of the sac.
Opposite each curve of the neck of the gall bladder, the mucous membrane pro-
jects inwards so as to form a large valvular fold. The mucous membrane is
covered by columnar epithelium, and secretes an abundance of thick viscid mucus;
it, is continuous through the hepatic duct with the mucous membrane lining the
ducts of the liver, and through the ductus communis choledocus with the mucous
membrane of the alimentary canal.
The Biliary Ducts are the hepatic, the cystic, and the ductus communis
choledocus.
The Hepatic Duct is formed of two trunks of nearly equal size, which issue
from the liver at the transverse flssure, one from the right and one from the left
lobe; these unite, and pass downwards and to the right for about an inch and a
half to join at an acute angle with the cystic duct, to form the common choledic
duct.
The Cystic Duct, the smallest of the three biliary ducts, is about an inch in
length. It passes obliquely downwards and to the left from the neck of the gall
bladder, and joins the hepatic duct to form the common duct. It lies in the
gastro-hepatic omentum in front of the vena cava, the cystic artery lying to its
left side. The mucous membrane lining its interior is thrown into a series of
crescentic folds, from five to twelve in number, which project into the duct in
regular succession, and are directed obliquely round the tube, presenting much the
appearance of a continuous spiral valve. They exist only in the human subject.
When the duct has been distended, the interspaces between the folds are dilated,
so as to give to its exterior a sacculated appearance.
The Ductus communis choledocus, the largest of the three, is the common
excretory duct of the liver and gall bladder. It is about three inches in length,
of the diameter of a goose-quill, and formed by the junction of the cystic and
PANCREAS. 621
hepatic ducts. It descends along the right border of the lesser omentum, behind
the first portion of the duodenum, in front of the vena portte, and to the right of
the hepatic artery; it then passes between the pancreas and descending portion of
the duodenum, and running for a short distance along the right side of the pan-
creatic duct, near its termination, passes with it obliquely between the mucous and
muscular coats, the two opening by a common orifice upon the summit of a papilla,
situated at the inner side of the descending portion of the duodenum, a little
below its middle.
Structure. The coats of the biliary ducts are composed of an external or fibrous
and an internal or mucous layer. The fibrous coat is composed of a strong areolar
fibrous tissue. The mucous coat is continuous with the lining membrane of the
hepatic ducts and gall bladder, and also with that of the duodenum. It is provided
with numerous glands, the orifices of which are scattered irregularly in the larger
ducts, but in the smaller hepatic ducts are disposed in two longitudinal rows, one on
each side of the vessel. These glands are of two kinds. Some are ramified tubes,
which occasionally anastomose, and from the sides of which saccular dilatations
are given off; others are small clustered cellular glands, which open either sepa-
rately into the hepatic duct, or into the ducts of the tubular glands.
The Pancreas.
Dissection. The pancreas may be exposed for dissection in three different ways : 1. By
raising the liver, drawing down the stomach, and tearing through the gastro-hepatic
omentum. 2. By raising the stomach, the arch of the colon, and great omentum upwards,
and then dividing the inferior layer of the transverse meso-colon. 3. By dividing the
two layers of peritoneum, which descend from the great curvature of the stomach to
form the great omentum ; turning this organ upwards, and then cutting through the
ascending layer of the transverse mesocolon.
The Pancreas {irav-Kpea^, all jiesJi) is a conglomerate gland, analogous in its
structure to the salivary glands. In shape, it is transversely oblong, flattened
from before backwards, and bears some slight resemblance to a hammer, its right
extremity being broad, and presenting a sort of angular bend from above down-
wards, called the head; its left extremity gradually tapers to form the tail, the
intermediate portion being called the body. It is situated transversely across the
posterior wall of the abdomen, at the back of the epigastric and both hypochon-
driac regions. Its length varies from six to eight inches, its breadth an inch and
a half, and its thickness from half an inch to an inch, being thicker at its right
extremity and along its upper border. Its weight varies from two to three and a
half ounces, but it may reach six ounces.
The right extremity or head of the pancreas (fig. 323) is curved upon itself
from above downwards, and is embraced by the concavity of the duodenum. The
common bile duct descends behind, between the duodenum and pancreas; and the
pancreatico-duodenal artery descends in front between the same parts. Upon its
posterior part is a lobular fold of the gland, which passes transversely to the left,
behind the superior mesenteric vessels, forming the posterior part of the canal, in
which they are contained. It is sometimes detached from the rest of the gland,
and is called the lesser pancreas.
The lesser end or tail of the pancreas is narrow; it extends to the left as far
as the spleen, and is placed over the left kidney and supra-renal capsule.
The body of the pancreas is convex in front, and covered by the ascending
layer of the transverse mesocolon and the posterior surface of the stomach.
The posterior surface is concave, and has the following structures interposed
between it and the first lumbar vertebra. The superior mesenteric artery and
vein, and commencement of the vena portfe, the vena cava, the aorta, the left
kidney, supra-renal capsule, and corresponding renal vessels.
The upper border is thick, and has resting upon it, near its centre, the coeliac
axis; the splenic artery and vein are lodged in a deep groove or canal in this
622
ORGANS OF DIGESTION.
border; and to the right, the first part of the duodenum and the hepatic artery
are in relation with it.
The loioer border, thinner than the upper, is separated from the transverse
portion of the duodenum by the superior mesenteric artery and vein; to the left
of this the inferior mesenteric vein ascends behind it to join the splenic vein.
The Pancreatic Duct, called the canal of Wirsung from its discoverer, extends
transversely from left to right through the substance of the pancreas, nearer to its
lower than its upper border, and lying nearer its anterior than its posterior sur-
face. In order to expose it, the superficial portion of the gland must be removed.
It commences by an orifice common to it and the ductus communis choledocus
upon the summit of an elevated papilla, situated at the inner side of the descending
333. — The Pancreas and its Relations.
portion of the duodenum, a little below its middle. Passing very obliquely
through the mucous and muscular coats, it separates itself from the common
choledic duct, and, ascending slightly, runs from right to left through the middle
of the gland, giving off numerous branches, which pass to be distributed to its
separate lobules.
Sometimes the pancreatic and common choledic ducts open separately into the
duodenum. The excretory duct of the lesser pancreas is called the ductus pan-
creaticus minor ; it opens into the main duct near the duodenum, and sometimes
separately into that intestine, at a distance of an inch or more from the termina-
tion of the principal duct.
The pancreatic duct, near the duodenum, is about the size of an ordinary quill;
its walls are thin, consisting of two coats, an external fibrous and an internal
mucous; the latter is thin, smooth, and furnished, near its termination, with a few
scattered follicles.
Sometimes the pancreatic duct is double, up to its point of entrance into the
duodenum.
In structure, the pancreas resembles that of the salivary glands; but it is looser
and softer in its texture.
The arteries of the pancreas are derived from the splenic, the pancreatico-
duodenal branch of the hepatic, and the superior mesenteric.
i
SPLEEN. 623
Its veins open into the splenic and superior mesenteric veins.
Its lymphatics terminate in tlie lumbar glands.
The nerves are filaments from the splenic plexus.
The Spleen.
The spleen is usually classified together with the thyroid, supra-renal glands,
and thymus, as one of the ductless glands, from its possessing no excretory duct.
It is of an oblong flattened form, soft, of very brittle consistence, highly vascular,
of a dark bluish-red colour, and situated in the left hypochondriac region, em-
bracing the cardiac end of the stomach. It is invested by peritoneum, and
connected with the stomach by the gastro-splenic omentum.
Relations. Its external surface is convex, smooth, and in relation with the
under surface of the Diaphragm, which separates it from the ninth, tenth, and
eleventh ribs of the left side.
The internal surface is slightly concave, and divided by a vertical fissure, the
hilus, into an anterior or larger, and a posterior or smaller portion. The hilus is
pierced by several large, irregular apertures, for the entrance and exit of vessels
and nerves. At the margins of the hilus, the two layers of peritoneum are
reflected from the surface of the organ on to the cardiac end of the stomach,
forming the gastro-splenic omentum, which contains between its layers the splenic
vessels and nerves, and the vasa brevia. The internal surface is in relation, in
front, with the great end of the stomach; below, with the tail of the pancreas;
and behind, with the left crus of the Diaphragm and corresponding supra-renal
capsule.
Its upper end, thick and rounded, is in relation with the Diaphragm, to which
it is connected by a fold of peritoneum, the suspensory ligament.
Its loioer end is pointed; it is in relation with the left extremity of the trans-
verse arch of the colon.
Its anterior margin is free, rounded, and often notched, especially below.
Its posterior margin is rounded, and lies in relation with the left kidney, to
which it is connected by loose areolar tissue.
The spleen is held in its position by two folds of peritoneum; one, the gastro-
splenic omentum, connects it with the stomach ; and the other, the suspensory
ligament, with the under surface of the Diaphragm.
The size and weight of the spleen are liable to very extreme variations at
different periods of life, in different individuals, and in the same individual under
different conditions. In the adult, in whom it attains its greatest size, it is usually
about five inches in length, three or four inches in breadth, and an inch or an inch
and a half in thickness, and weighs about seven ounces. At hirth, its weight, in
proportion to the entire body, is almost equal to what is observed in the adult,
being as I to 350 ; whilst in the adult it varies from i to 320 and 400. In old
age, the organ not only decreases in weight, but decreases considerably in pro-
portion to the entire body, being as i to 700. The size of the spleen is increased
during and after digestion, and varies considerably, according to the state of
nutrition of the body, being large in highly fed, and small in starved animals.
In intermittent and other fevers, it becomes much enlarged, weighing occasion-
ally from 18 to 20 pounds.
Structure. The spleen is invested by two coats ; an external serous, and an
internal fibrous elastic coat.
The external, or serous coat, is derived from the peritoneum; it is thin, smooth,
and in the human subject intimately adherent to the fibrous elastic coat. It
invests almost the entire organ; being reflected from it, at the hilus, on to the
great end of the stomach, and at the upper end of the organ on to the Dia-
phragm.
The fibrous elastic coat forms the framework of the spleen. It invests the
exterior of the organ, and at the hilus is reflected inwards upon the vessels in the
624
OEGANS OF DIGESTION.
form of vaginae or sheaths. From these sheaths, as well as from the inner surface
of the fibro-elastic coat, numerous small fibrous bands, trabeculcB (fig. 324), are
given off in all directions; these uniting, constitute the areolar framework of the
spleen. The proper coat, the sheaths of the vessels, and the trabecules, consist of
324- — Transverse Section of the Spleen, showing the Trabecular Tissue,
and the Splenic Vein and its Branches.
a dense mesh of the white and yellow elastic fibrous tissues, the latter consider-
ably predominating. It is owing to the presence of this tissue, that the spleen
possesses a considerable amount of elasticity, admirably adapted for the very
considerable variations in size that it presents under certain circumstances. In
some of the mammalia, in addition to the usual constituents of this tunic, are
found numerous pale, flattened, spindle-shaped, nucleated fibres, like unstriped
muscular fibre. It is probably owing to this structure, that the spleen possesses,
when acted upon by the galvanic current, faint traces of contractility.
The proper substance of the spleen occupies the interspaces of the areolar
framework of the organ; it is a soft, pulpy mass, of a dark reddish-brown colour,
consisting of colourless and coloured elements.
The colourless elements consist of granular matter ; nuclei, about the size of
the red blood-discs, homogeneous or gi-anular in structure; and nucleated vesicles
in small numbers. These elements form, probably, one-half or two-thirds of the
whole substance of the pulp, filling up the interspaces formed by the partitions of
the spleen, and lying in close contact with the walls of the capillary vessels, so as
to be readily acted upon by the nutrient fluid which permeates them. These
elements form a lai-ge part of the entire bulk of the spleen in well-nourished
animals; whilst they diminish in number, and occasionally are not found at all, in
starved animals. The application of chemical tests shows that they are essen-
tially a proteine compound.
The coloured elements of the pulp consist of red blood-globules and of coloured
corpuscles, either free, or included in cells. Sometimes, unchanged blood-discs
are seen included in a cell ; but more frequently the included blood-discs are
altered both in form and colour. Besides these, numerous deep-red, or reddish-
yellow, or black corpuscles and crystals, either single or aggregated in masses, are
seen diffused throughout the pulp-substance : these, in chemical composition, are
closely allied to the haematin of the blood.
STRUCTURE OF SPLEEN. 625
MalpigUan Corpuscles. On examining the cut surface of a healthy spleen, a
number of small semi-opaque bodies, of gelatinous consistence, are seen dissemi-
nated throughout its substance ; these are the splenic or Malpighian corpuscles
(fig. 325). They may be seen at all periods of life; but they are more distinct in
325.— The Malpighian Corpuscles, and their Eelatiou with the Splenic Artery
and its Branches.
early, than in adult life or old age ; and they are much smaller in man, than in
most mammalia. They are of a spherical or ovoid form, vary considerably in
size and number, and are of a semi-opaque whitish colour. They are appended
to the sheaths of the smaller arteries and their branches, presenting a resemblance
to the buds of the moss rose. Each consists of a membranous capsule, composed
of fine pale fibres, which interlace in all directions. In man, the capsule is homo-
geneous in structure, and formed by a prolongation from the sheaths of the small
arteries to which the corpuscles are attached. The blood-vessels ramifying on
the surface of the corpuscles, consist of the larger ramifications of the arteries to
which the sacculus is connected; and also of a delicate capillary plexus, similar
to that surrounding the vesicles of other glands. These vesicles have also a
close relation with the veins (fig. 326). These vessels, which are of consider-
able size even at their origin, commence on the surface of each vesicle throughout
the whole of its circumference, forming a dense venous mesh, in which each of
these bodies is enclosed. It is probable, that from the blood contained in the
capillary network, the material is separated which is occasionally stored up in
their cavity; the veins being so placed as to carry ofi^, under certain conditions,
those contents that are again to be discharged into the circulation. Each cap-
sule contains a soft, white, semi-fluid substance, consisting of granular matter,
nuclei similar to those found in the pulp, and a few nucleated cells, the composi-
tion of which is apparently albuminous. These bodies are very large after the
early periods of digestion, in well-fed animals, and especially in those fed upon
albuminous diet. In starved animals, they disappear altogether.
The Splenic Artery is remarkable for its large size," in proportion to the size
s s
626
OEGANS OF DIGESTION.
of the organ; and also for its tortuous course. It divides into from four to six
branches, which enter the hilus of the organ, and ramify throughout its substance
326. — One of the Splenic Corpuscles, showing its Relations
with the Blood-vessels.
(fig. 327), receiving sheaths from an involution of the external fibrous tunic,
the same sheaths also investing the nerves and veins. Each branch runs in the
transverse axis of the organ, from within outwards, diminishing in size during its
327. — Transverse Section of the Human Spleen, showing the Distribution
of the Splenic Artery and its Branches.
transit, and giving off, in its passage, smaller branches, some of which pass to the
anterior, others to the posterior part : these ultimately terminate in ihe proper
substance of the spleen, in small tufts or pencils of capillary vessels, which lie in
STRUCTURE OF SPLEEN. 627
direct contact with the pulp. Each of the larger branches of the artei-y supplies
chiefly that region of the organ in which the branch raniilies, having no anasto-
mosis with the majority of the other branches.
The Capillaries, supported by the minute trabecula;, traverse the pulp in all
directions, and terminate either directly in the veins, or open into lacunar spaces,
from Avhich the veins originate.
The Veins are of large size, as compared with the size of the organ ; and their
distribution is limited, like that of the arteries, to the supply of a particular part
of the gland; they are much larger and more numerous than the arteries. They
originate, ist, as continuations of the capillaries of the arteries; 2nd, by inter-
cellular spaces communicating with each other; 3rd, by distinct cascal pouches.
By their junction they form from four to six branches, which emerge from the
hilus; and these uniting, form the splenic vein, the largest branch of the vena
porta3.
The Lymphatics form a deep and superficial set ; they pass through the
lymphatic glands at the hilus, and terminate in the thoracic duct.
The Nerves are derived from branches of the right and left semilunar ganglia,
and right pneumogastric nerve.
S S 2
The Thorax.
THE Thorax is a conical, osseous framework, connected with the middle
region of the spine. It is the largest of the three cavities of the trunk,
narrow above, broad below, flattened before and behind, and somewhat cordiform
on a transverse section.
Boundaries. It is bounded in front by the sternum, the six upper costal
cartilages, the ribs, and intercostal muscles; at the sides, by the ribs and inter-
costal muscles; and behind, by the same structures and the dorsal portion of the
vertebral column.
The Superior Opening of the thorax is bounded on each side by the first rib;
in front, by the upper border of the sternum ; and behind, by the first dorsal
vertebra. It is broader from side to side, than from before backwards; and its
direction is backwards and upwards.
The Loioer Opening, or Base, is bounded in front by the ensiform cartilage;
behind, by the last dorsal vertebra ; and on each side by the last rib, the Dia-
phragm filling in the intervening space. Its direction is obliquely downwards
and backwards; so that the cavity of the thorax is much deejjer on the posterior,
than on the anterior Avail. It is wider transversely than from before backwards,
and its general direction is convex towards the chest; but it is more flattened at the
centre than at the sides, and rises higher on the ri^ht than on the left side, corre-
sponding in the dead body to the upper border of the fifth rib, near the sternum,
on the right side; and to the corresponding part of the sixth rib on the left
side.
The parts which pass through the upper opening of the thorax are, from before
backwards, the Sterno-hyoid and Sterno-thyroid muscles, the remains of the
thymus gland, the trachea, oesophagus, thoracic duct, and the Longi colli muscles;
on the sides, the arteria innominata on the right, the left carotid and left sub-
clavian arteries, the internal mammary and superior intercostal arteries, the right
and left venje innominatas, the pneumogastric, symj)athetic, phrenic, and cardiac
nerves, and the recurrent laryngeal nerve of the left side. The apex of each
lung, covered by the pleura, also projects through this aperture, a little above the
margin of the first rib.
The viscera contained in the thoracic cavity are, the great central organ of
circulation, the heart, enclosed in its membranous bag, the pericardium; and the
organs of respiration, the lungs, invested by the pleurae.
The Pericardium.
The pericardium is a conical membranous sac, in which the heart and the
commencement of the great vessels are contained. It is placed behind the sternum,
and the cartilages of the fourth, fifth, sixth, and seventh ribs of the left side, in
the interval between the pleurae.
Its apex is directed upwards, and surrounds the great vessels about two inches
above their origin from the base of the heart. Its base is attached to the central
tendon of the Diaphragm, extending a little farther to the left than the right side.
In front, it is separated from the sternum by the remains of the thymus gland
above, and a little loose areolar tissue below; and is covered by the margins of
the lungs, especially the left. Behind, it rests upon the bronchi, the oesophagus, and
the descending aorta. Laterally, it is covered by the pleurae; the phrenic vessels
and nerve descending between the two membranes on either side.
PERICARDIUM. 629
The Pericardium is a fibro-serous membrane, and consists, tlaerefore, of two
layers: an external fibrous, and an internal serous.
The fibrous layer is a strong, dense fibrous membrane. Above, it surrounds
the great vessels arising from the base of the heart, on whiclx it is continued in
the form of tubular prolongations, which are gradually lost upon their external
coats; the strongest being that which encloses the aorta. Below, it is attached
to the central tendon of the Diaphragm, and, on the left side, to its muscular
fibres.
The vessels receiving fibrous prolongations from this membrane are the aorta,
the superior vena cava, and the pulmonary arteries and veins. As the inferior
cava enters the pericardium, through the central tendon of the Diaphragm, it
receives no covering from the fibrous layer.
The serous layer invests the heart, and is then reflected on the inner surface
of the pericardium. It consists, therefore, of a visceral and a parietal portion.
The former invests the surface of the heart, and the commencement of the great
vessels, to the extent of two inches from their origin; from these it is reflected
upon the inner surface of the fibrous layer, lining, below, the upper surface of the
central tendon of the Diaphragm. The serous membrane encloses the aorta and
pulmonary artery in a single tube; but it only partially covers the superior and
inferior vena cavae, and the four pulmonary veins. Its inner surface is smooth
and glistening, and secretes a thin fluid, which serves to facilitate the movements of
the contained organ.
The arteries of the pericardium are derived from the internal mammary, the
bronchial, the oesophageal, and the phrenic.
The Heart.
The heart is a hollow muscular organ, of a conical form, placed between the
lungs, and enclosed in the cavity of the jaericardium.
Position. The heart is placed obliquely in the chest: the broad attached end,
or base, is directed upwards and backwards to the right, and corresponds to the
interval between the fifth and eighth dorsal vertebrge: the apex is directed down-
wards and forwards to the left, and corresponds to the interspace between the
cartilages of the fifth and sixth ribs, one inch to the inner side, and two inches
below the left nipple. The heart projects further into the left than into the
right cavity of the chest, extending from the median line about three inches in
the former direction, and only one and a half in the latter. Its upper border
would correspond to a line drawn across the sternum, on a level with the upper
border of the third costal cartilage; and its lower border, to a line drawn across
the lower end of the same bone, from the costo-xiphoid articulations of the right
side, to the part corresponding to the apex. Its upper surface is rounded and
convex, directed upwards and forwards, and formed chiefly by the right ventricle
and part of the left. Its under sui-face is flattened, and rests upon the Diaphragm.
Of its two borders, the right is the longest and thinnest, the left shorter, but
thick and round.
Size. The heart, in the adult, measures about five inches in length, three
inches and a half in the broadest part of its transverse diameter, and two inches
and a half in its antero-posterior. The prevalent weight, in the male, varies
from ten to twelve ounces; in the female, from eight to ten: its proportion to the
body being as i to 169, in males; i to 149, in females. The heart continues
increasing in weight, and also in length, breadth, and thickness, up to an advanced
period of life; and this is more marked in men than in women.
The heart is subdivided by a longitudinal muscular septum, into two lateral
halves, which are named respectively, from their position, right and left; and a
transverse constriction divides each half of the organ into two cavities, the upper
cavity on each side . being called the auricle, the lower the ventricle. The right
is the venous side of the heart, receiving into its auricle the dark venous blood
from the entire body, by the superior and inferior cavae, and coronary sinus.
630
THE THOEAX.
From the auricle, the blood passes into the right ventricle; and from the right
ventricle, through the pulmonary artery, into the lungs. The blood, arterialized
by its passage through the lungs, is returned to the left side of the heart by the
pulmonary veins, which open into the left auricle; from the left auricle the blood
passes into the left ventricle, and from the left ventricle is distributed, by the
aorta and its subdivisions, through the entire body. This constitutes the circula-
tion of the blood in the adult.
This division of the heart into four cavities, is indicated upon its surface in the
form of grooves. Thus, the great transverse groove separating the auricles from
the ventricles, is called the auriculo-ventricular groove. It is deficient, in front,
from being crossed by the root of the pulmonary artery, and contains the trunk
of the nutrient vessels of the heart. The auricular portion occupies the base of
the heart, and is subdivided into two cavities by a median septum. The two
ventricles are also separated into a right and left, 1by two longitudinal furrows,
which are situated, one on its anterior, the other on its posterior surface: these
extend from the base to the apex of the organ: the former being situated nearer
to the left border of the heart, and the latter to the right. It follows, therefore,
that the right ventricle forms the greater portion of the anterior surface of the
heart, and the left ventricle more of its posterior surface.
Each of these cavities should now be separately examined.
The Right Auricle is a little larger than the left, its walls somewhat thinner,
measuring about one line; and its cavity is capable of containing about two
ounces. It consists of two parts, a principal cavity, or sinus, and an appendix
auriculas.
The sinus is the large quadrangular-shaped cavity, placed between the two
venge cava3: its walls are extremely thin, and it is connected below with the right
328. — The Right Auricle and Ventricle laid open,
the Anterior Walls of both being removed.
2 Oerrit*
Bj-Lsllc ^aiisecl -through.
Sight Auricula -Vattricu l(t,T' opencna
ventricle, and internally, with the left auricle, being free in the rest of its
extent.
HEART; RIGHT AURICLE. 631
The appendix auricula, so called from its fancied resemblance to a dog's ear,
is a small conical muscular pouch, the margins of which present a dentated
edge. It projects from the sinus forwards and to the left side, overlapping the
root of the pulmonary artery.
To examine the interior of the auricle, a transverse incision should be made along its
ventricular margin, from its right border to the appendix ; and, from the middle of this, a
second incision should be carried upwards, along tlie inner side of the two vense cavse.
The following parts present themselves for examination :
( Superior cava.
\ Inferior cava. , _, , . .
^ . J ^ . XT- 1 I Eustachia
(Jpenings. < Coronary smus. Valves < p .
/ Foramina Thebesii. *■ '''
Auriculo-ventricular.
Relics of Fcetal | Annulus ovalis.
structure | Fossa ovalis.
Musculi pectinati.
Openings. The Superior Vena Cava returns the blood from the upper half of
the body, and opens into the upper and front part of the auricle, the direction of
its orifice being downwards and forwards.
The Inferior Vena Cava, larger than the superior, returns the blood from the
lower half of the body, and opens into the lowest part of the auricle, near the
septum, the direction of its orifice being upwards and inwards. The direction of
a current of blood through the superior vena cava, would consequently be towards
the auriculo-ventricular orifice; whilst the direction of the blood through the
inferior cava, would be towards the auricular septum. This is the normal
direction of the two currents in foetal life.
The Tuberculum Loweri is a small projection on the right wall of the auricle,
between the two cavse. This is most distinct in the hearts of quadrupeds: in
man, it is scarcely visible. It was supposed by Lower, to direct the blood from
the superior cava towards the auriculo-ventricular opening.
The Coronary Sinus opens into the auricle, between the inferior vena cava,
and the auriculo-ventricular opening. It returns the blood from the substance of
the heart, and is protected by a semicircular fold of the lining membrane of the
auricle, the coronary valve. The sinus, before entering the auricle, is consi-
derably dilated. Its wall is partly muscular, and, at its junction with the great
coronary vein, is somewhat constricted, and furnished with a valve, consisting of
two unequal segments.
The Foramina Thebesii are numerous minute apertures, the mouths of small
veins {vence cordis minimce), which open on various parts of the surface of the
auricle. They return the blood directly from the muscular substance of the
heart. Some of these foramina are minute depressions in the walls of the heart,
presenting a closed extremity.
The Auriculo- Ventricular Opening is the large oval aperture of communica-
tion between the auricle and ventricle, to be presently described.
Valves. The Eustachian Valve is situated between the anterior margin of the
inferior cava, and the auriculo-ventricular orifice. It is semilunar in form, its
convex margin attached to the wall of the vein; its concave margin, which is
free, terminating in two cornua, of which the left is attached to the anterior edge
of the annulus ovalis; the right being lost on the wall of the auricle.
In the foetus, this valve is of large size, and serves to direct the blood from the
inferior cava, through the foramen ovale, into the left auricle.
In the adult, it is occasionally persistent, and may assist in preventing the
reflux of blood into the inferior cava: more commonly, it is small, and its free
margin presents a cribriform, or filamentous appearance: occasionally, it is alto-
632 , THE THORAX.
gether wanting. It is formed by a duplicature of the lining membrane of the
auricle, containing a few muscular fibres.
The Coronary Valve is a semicircular fold of the lining membrane of the
auricle, protecting the orifice of the coronary sinus. It prevents the regurgitation
of blood into the sinus during the contraction of the auricle. This valve is
occasionally double.
The Fossa Ovalis is an oval depression, corresponding to the situation of the
foramen ovale in the foetus. It is situated at the lower part of the septum
auricularum, above the orifice of the inferior vena cava.
The Annulus Ovalis is the prominent oval mai-gin of the foramen ovale. It is
most distinct above, and at the sides; below, it is deficient. A small slit-like
valvular opening is occasionally found, at the upper margin of the fossa ovalis,
which leads upwards, beneath the annulus, into the left auricle, it is the remains of
the aperture between the two auricles in the foetus. '
The Musculi Pectinati are small, prominent muscular columns, running trans-
versely across the inner surface of the appendix auriculee, and adjoining portion
of the wall of the sinus. They have received the name, pectinati, from the fancied
resemblance they bear to the teeth of a comb.
The Right or Anterior Ventricle is somewhat triangular in form, and
extends from the right auricle to near the apex. Its anterior or upper surface is
rounded and convex, and forms the larger part of the front of the heart. Its pos-
terior or under surface is flattened, rests upon the Diaphragm, and forms only a
small part of this surface. Its inner wall is formed by the partition between the
two ventricles, the septum ventriculorum, the surface of which is convex, and
bulges into the cavity of the right ventricle. Superiorly, the ventricle forms a
conical prolongation, the infundibichim, or conus arteriosus, from which the pul-
monary artery arises. The walls of the right ven'tricle are thinner than those of
the left, the proportion between them being as i to 2 (Bizot). The thickest part
of the wall is at the base, and it gradually becomes thinner towards the apex.
Its cavity, which equals that of the left ventricle, is capable of containing about
two fluid ounces.
To examine its interior, an incision should be made a little to the right of the anterior
ventricular groove from the pulmonary artery to the apex of the heart, and from thence
carried up along the right border of the ventricle, as far as the auriculo-ventricular
opening.
The following parts present themselves for examination:
^ . ( Auriculo-ventricular.
to • • I Opening of the Pulmonary Artery.
XT 1 ( Tricuspid.
Valves . . . { c^ .1
I bemilunar.
And a muscular and tendinous apparatus connected with the tricuspid valves.
Columnge carnese. Chordae tendinese.
The Auriculo- Ventricular Orifice is the large oval aperture of communication
between the auricle and ventricle. It is situated at the base of the right ventricle,
near the right border of the heart, and corresponds to the sternum between the
third costal cartilages. The opening is about aninch in diameter, oval from side to
side, surrounded by a fibrous ring, covered by the lining membrane of the heart, and
is rather larger than the corresponding aperture on the left side, being sufiiciently
large to admit the ends of three fingers. It is guarded by the tricuspid valve.
The Opening of the Pulmonary Artery is circular in form, and situated at the
summit of the conus arteriosus, close to the septum ventriculorum. It is placed
on the left side, and in front of the auriculo-ventricular opening, upon the anterior
aspect of the heart, and corresponds to the upper border of the third costal carti-
lage of the left side, close to the sternum. Its orifice is guarded by the semilunar
valves.
HEART; RIGHT VENTRICLE. 633
The Tricuspid Valve consists of three segments of a trianguLir or trapezoidal
shape, formed by a duplicature of the lining membrane of the heart, strengthened
by a layer of fibrous tissue, and containing, according to KUrschner and Senac,
muscular fibres. These segments are connected by their bases to the auriculo-
ventricular orifice, and by their sides with one another, so as to form a continuous
annular membrane, which is attached around the margin of the auriculo-ventricular
opening, their free margin and ventricular surfaces affording attachment to a number
of delicate tendinous cords, the choreics tendinece. The largest of these three seg-
ments is placed towards the left side of the auriculo-ventricular opening inter-
posed between it and the pulmonary artery, so as to prevent the filling of that
tube during the distension of the ventricle. Another segment corresponds to the
front of the ventricle; and a third to its posterior wall. The central part of each
segment is thick and strong; and the lateral margins thin and indented. The
chordae tendinece are connected with the adjacent margins of the principal seg-
ments of the valve, and are further attached to each segment in the following
manner : i . Three or four reach the attached margin of each segment, where they
are continuous with the auriculo-ventricular tendinous ring. 2. Others, four to
six in number, are attached to the central thickened part of each segment, 3. The
most numerous and finest are connected with the marginal portion of each
segment.
The ColumncB Carnece. are the rounded muscular columns which are ob-
served projecting from the whole of the inner surface of the ventricle, excepting
the infundibulum, and interlacing in every direction. They may be classified
according to their mode of connection with the ventricle, into three sets. The
first set merely form prominent ridges on the inner surface of the ventricle, being
attached their entire length on one side, as well as by their extremities. The
second set are attached by their two extremities, but are free in the rest of their
extent; whilst the third set {columnce papillares), three or four in number, are
attached by one extremity to the wall of the heart, the opposite extremity
giving insertion to the chordos tendinece.
The Semilunar Valves, three in number, guard the orifice of the pulmonary
artery. They consist of three semicircular folds, formed by a duplicature of the
lining membrane, strengthened by fibrous tissue. They are attached, by their
convex margins, to the wall of the artery, at its junction with the ventricle, the
straight border being free, and directed upwards in the course of the vessel,
against the sides of which they are pressed during the passage of the blood along
its canal. The free margin of each valve is somewhat thicker than the rest, and
strengthened by a bundle of tendinous fibres; it presents, at its middle, a small
projecting fibro-cartilaginous nodule, called corpus Arantii. From this nodule
tendinous fibres radiate through the valve to its attached margin, and these fibres
form a constituent part of its substance throughout its whole extent, excepting
two narrow lunated portions, placed one on either side of the nodule, immediately
behind the free margin; here the valve is thin, and formed merely by the lining
membrane. During the passage of the blood along the pulmonaiy artery, these
valves are pressed against the sides of its cylinder, and the course of the blood
along the tube is uninterrupted; but during the ventricular diastole, when the
current of blood along the pulmonary artery is checked, and partly thrown back
by its elastic walls, these valves become immediately expanded, and effectually
close the entrance of the tube. When the valves are closed, the lunated portions
of each are brought into contact with one another by their opposed surfaces, the
three fibro-cartilaginous nodules filling up the small triangular space that would
be otherwise left by the approximation of three semilunar folds.
Between the semilunar valves and the commencement of the pulmonary artery
are three pouches or dilatations, one behind each valve. These are the pulmonary
sinuses (sinuses of Valsalva). Similar sinuses exist between the semilunar valves
and the commencement of the aorta; they are larger than the pulmonary sinuses.
The Left Aukicle is rather smaller but thicker than the right, measuring about
634
THE THORAX.
one line and a half; it consists of two parts, a principal cavity or sinus, and an
appendix auriculae.
The sinus is cuboidal in form, and concealed in front by the pulmonary artery
and aorta; internally, it is separated from the right auricle by the septum auricu-
larum; and behind, it receives on each side the pulmonary veins, being free in the
rest of its extent.
The appendix auriculae is somewhat constricted at its junction with the auricle;
it is longer, narrower, and more curved than that of the right side, and its mar-
gins more deeply indented, presenting a kind of foliated appearance. Its direction
is forwards towards the right side, overlapping the root of the pulmonary
artery.
In order to examine its interior, a horizontal incision should be made along the attached
border of the auricle to the ventricle, and from the middle of this a second incision should
be carried upwards.
The following parts then present themselves for examination :
The Openings of the four Pulmonary Veins.
Auriculo-Ventricular Opening.
Musculi Pectinati.
The Pulmonary Veins, four in number, open two into the right, and two into
the left side of the auricle. The two left veins frequently terminate by a common
opening. They are not provided with valves.
329. — The Left Auricle and Ventricle laid open,
the Anterior Walls of both being removed.
il passed thr.
rtle openlna
The Auricula- Ventricular Opening is the large oval aperture of communication
between the auricle and ventricle. It is rather smaller than the corresponding
opening on the opposite side.
HEART; LEFT AURICLE AND VENTRICLE. 635
The Musctdi Pectinati are fewer in number and smaller tlian on the right side;
they are confined to the inner surface of the appendix.
On the inner surface of the septum auricular um may be seen a lunated impres-
sion, bounded below by a crescentic ridge, the concavity of Avhich is turned
upwards. It corresponds to the foramen ovale in the fcctus. This depression is
just above the fossa ovalis in the right auricle.
The Left Ventricle is longer and more conical in shape than the right ven-
tricle. It forms a small part of the left side of the anterior surface of the heart,
and a considerable part of its posterior surface. It also forms the apex of the
heart by its projection beyond the right ventricle. Its walls are much thicker
than those of the right ventricle, the proportion being as 2 to i (Bizot). They
are also thickest in the broadest part of the ventricle, becoming gradually thinner
towards the base, and also towards the apex, which is the thinnest part.
Its cavity should be opened by making an incision through its anterior wall along the
left side of the ventricular septum, and carrying it round the apes and along its posterior
surface to the aui'iculo-ventricular opening.
The following parts present themselves for examination:
I
Auriculo-ventricular. ^^ , (Mitral.
Semilunar.
Openings I ^^^^.^_ " ^^^^'^^
Chordas tendinete. Columnse carneiE.
The Auriculo-ventricular Opening is placed behind, and to the left side of,
the aortic orifice. This opening is a little smaller than the corresponding aper-
ture of the opposite side; and, like it, is broader in the transverse, than in the
antero-posterior diameter. Its position corresponds to the centre of the sternum.
It is surrounded by a dense fibrous ring, covered by the lining membrane of the
heart, and is guarded by the mitral valve.
The Aortic Opening is a small circular aperture, in front and to the right side
of the auriculo-ventricular, from which it is separated by one of the segments of
the mitral valve. Its orifice is guarded by the semilunar valves. Its position
corresponds to the junction of the third left costal cartilage with the sternum.
The Mitral Valve is attached to the circumference of the auriculo-ventricular
orifice, in the same way that the tricuspid valve is on the opposite side. It is
formed by a duplicature of the lining membrane, strengthened by fibrous tissue,
and contains a few muscular fibres. It is larger in size, thicker, and altogether
stronger than the tricuspid, and consists of two segments of unequal size. The
larger segment is placed in front, between the auriculo-ventricular and aortic
orifices, and is said to prevent the filling of the aorta during the distension of the
ventricle. Two smaller segments are usually found at the angle of junction of
the larger. The mitral valves are furnished with numerous chordse tendineae;
their mode of attachment is precisely similar to those on the right side; but they
are thicker, stronger, and less numerous.
The Semilunar Valves surround the orifice of the aorta; they are similar in
structure, and in their mode of attachment, to those of the pulmonary artery.
They are, however, larger, thicker, and stronger than those of the right side;
the lunula3 are more distinct, and the corpora Arantii larger and more prominent.
Between each valve and the cylinder of the aorta is a deep depression, the sinus
aortici (sinuses of Valsalva); they are larger than those at the root of the pulmo-
nary artery.
The ColumncB Carnecs admit of a subdivision into three sets, like those upon
the right side; but they are smaller, more numerous, and present a dense inter-
lacement, especially at the apex, and upon the posterior wall. Those attached by
one extremity only, the musculi papillares, are two in number, being connected
one to the anterior, the other to the posterior wall; they are of large size, and
terminate by free rounded extremities, from which. the chordie tendinea3 arise.
The Endocardium is the serous membrane which lines the internal surface of
636 THE THOEAX.
the heart; it assists in forming, by its reduplications, the valves contained in this
organ, and is continuous with the lining membrane of the great blood-vessels.
It is a thin, smooth, transparent membrane, giving to the inner surface of the
heart its glistening appearance. It is more opaque on the left, than on the right
side of the heart, thicker in the auricles than in the ventricles, and thickest in the
left auricle. It is thin on the musculi pectinati, and on the columnae carnete; but
thicker on the smooth part of the auricular and ventricular walls, and on the tips
of the musculi papillares.
Structure. The heart consists of muscular fibres, and of fibrous rings which
serve for their attachment.
The Fibrous Rings surround the auriculo-ventricular and arterial orifices: they
are stronger upon the left, than on the right side of the heart. The auriculo-
ventricular rings serve for the attachment of the muscular fibres of the auricles
and ventricles, and also for the mitral and tricuspid valves; the left one is closely
connected, by its right margin, with the aortic arterial ring. Between these and
the right auriculo-ventricular ring, is a fibro-cartilaginous mass; and in some of
the larger animals, as the ox and elephant, a portion of bone.
The fibrous rings surrounding the arterial orifices, serve for the attachment of
the great vessels and semilunar valves. Each ring receives, by its ventricular
margin, the attachment of the muscular fibres of the ventricles ; its opposite
margin presents three deep semicircular notches, within which the middle coat
of the artery (which presents three convex semicircular segments) is firmly fixed;
the attachment of the artery to its fibrous ring being strengthened by the thin
cellular coat and serous membrane extei'nally, and by the endocardium within.
It is opposite the margins of these semicircular notches, in the arterial rings, that
the endocardium, by its reduplication, forms the semilunar valves, the fibrous
structure of the ring being continued into each of the segments of the valve at
this part. The middle coat of the artery in this situation is thin, and the sides of
the vessel dilated to form the sinuses of Valsalva.
The Muscular Structure of the heart consists of bands of fibres, which present
an exceedingly intricate interlacement. They are of a deep red colour, involun-
tary, but marked with transverse stride.
The muscular fibres of the heart admit of a subdivision into two kinds; those
of the auricles, and those of the ventricles ; which are quite independent of one
another.
Fibres of the Auricles. These are disposed in two layers; a superficial layer
common to both cavities, and a deep layer proper to each. The superficial fibres
are most distinct on the anterior surface of the auricles, across the bases of which
they run in a transverse direction, forming a thin, but incomplete, layer. Some
of these fibres pass into the septum auricularum. The internal or deep fibres
proper to each auricle consist of two sets, looped, and annular fibres. The looped
fibres pass upwards over each auricle, being attached by both extremities to the
corresponding auriculo-ventricular rings, in front and behind. The annular fibres
surround the whole extent of the appendices auriculae, and are continued upon
the walls of the veniB cavte and coronary sinus on the right side, and upon the
pulmonary veins on the left side, at their connection with the heart. In the
appendices, they interlace with the longitudinal fibres.
Fibres of the Ventricles. These, as in the auricles, are disposed in layers, some
of which are common to both ventricular cavities, whilst others belong exclusively
to one ventricle, the latter being chiefly found towards the base of the heart.
The greater majority of these fibres are connected by both ends with the auriculo-
ventricular fibrous rings, either directly or indirectly through the chordse ten-
dinete; some, however, are attached to the fibrous rings surrounding the arterial
orifices.
The superficial fibres are either longitudinal, or more commonly oblique or
spiral in their direction, and towards the apex are arranged in the form of twisted
loops; the deeper fibres are circular.
STRUCTURE OF HEART. 637
The Spiral fibres are disposed in layers of various degrees of thickness: the
most superficial, on the front of the ventricles, run obliquely from right to left,
and from above downwards. On the back of the ventricles they are directed
more vertically, and pass from left to right.
The superficial fibres coil inwards at the apex of the heart, around which
they are arranged in a whorl-like form, called the vortex, dipping beneath the
edge of the deeper and shorter layers. If these fibres are carefully uncoiled, in
a heart previously boiled, the cavity of the left, and then that of the right ven-
tricle, will be exposed at this point. The layers of fibres successively met with,
have a similar arrangement; the more superficial and longer turning inwards, and
including the deeper and shorter bands. All these fibres ascend and spread out
upon the inner surface of the ventricles, foi-ming the walls, the septum, and the
musculi papillares, which project from these cavities; and they are finally in-
serted into the auriculo-ventricular fibrous rings, or, indirectly, through the
chordae tendineas. Of these spiral fibres, some enter at the interventricular
furrows, and surround either ventricle singly; others pass across the furrows and
embrace both cavities. On tracing those which form the vortex, back into the
interventricular septum, they become interlaced with similar fibres from the right
ventricle, and ascend vertically upon the right side of the septum, as far as its
base, in the form of a long and broad band.
Circular Fibres. The circular fibres are situated deeply in the substance of
the heart ; towards the base they enter the anterior and posterior longitudinal
furrows, so as to include each cavity singly, or, passing across them, surround
both ventricles, more fibres passing across the posterior than the anterior furrow.
They finally ascend in the substance of the ventricle, to be inserted into the fibrous
rings at its base.
Vessels and Nerves. The arteries supplying the heart, are the anterior and
posterior coronary.
The veins accompany the arteries, and terminate in the right auricle. They
are the great cardiac vein, the small, or anterior cardiac veins, and the vente
cordis minim^e (vence Thebesii).
The lymphatics terminate in the thoracic and right lymphatic ducts.
The nerves are derived from the cardiac plexuses, which are formed partly
from the spinal, and partly from the sympathetic system. In their distribution
throughout its substance, they are furnished with small ganglia, which have been
figured both by Remak and Lee.
Peculiarities in the Vascular System of the Fcetus.
The chief peculiarities in the heart of the fcetus, are the direct communication
between the two auricles by the foramen ovale, and the large size of the
Eustachian valve. There are also several minor peculiarities. Thus, the posi-
tion of the heart is vertical until the fourth month, when it commences to assume
an oblique direction. Its size is also very considerable, as compared with the
body, the proportion at the second month being as I to 50: at birth, it is as
I to 120: whilst, in the adult, the average is about l to 160. At an early
period of foetal life, the auricular portion of the heart is larger than the ventricu-
lar, the right auricle being more capacious than the left; but, towards birth, the
ventricular portion becomes the larger. The thickness of both ventricles is, at
first, about equal; but, towards birth, the left becomes much the thicker of the
two.
The Foramen Ovale is situated at the lower and back part of the septum
auricularum. It attains its greatest size at the sixth month.
The Eustachian Valve is developed from the anterior border of the inferior
vena cava, at its entrance in the auricle, and, rising up on the left side of the
opening of this vein, serves to direct the blood from the inferior vena cava
through the foramen ovale into the left auricle.
638
THE THORAX.
The peculiarities in the arterial system of the foetus are the communication
between the pulmonary artery and descending aorta, by means of the ductus
arteriosus, and the communication between the common iliac arteries and the
placenta, by the umbilical arteries.
The Ductus Arteriosus is a short tube, about half an inch in length at birth,
and of the diameter of a goose-quill. It connects the left branch of the pulmo-
nary artery with the termination of the arch of the aorta, just beyond the origin
330. — Plan of the Pcetal Circulation.
ntevita I Ili.ac' A.
In this plan the figured arrows represent the Ivind of blood, as well as the direction
which it takes in the vessels. Thus — arterial blood is figured 2*^ ••5>; venous blood,
5^1- •^; mixed (arterial and venous blood), ;g^.— .>.
FCETAL CIRCULATION. 639
of the left subclcavian artery. It serves to conduct the chief part of the blood of
the right ventricle into the descending aorta.
The Umbilical, or Hypogastric Arteries, arise from the internal iliacs, in
addition to the usual branches given olF from these vessels in the adult. Ascend-
ing along the sides of the bladder to its fundus, they pass out of the abdomen at
the umbilicus, and are continued along the umbilical cord to the placenta, coiling
round the umbilical vein. They return the blood to the placenta which has
been circulated in the system of the foetus.
The peculiarity in the venous system of the foetus is the communication
established between the placenta, and the liver and portal vein, through the um-
bilical vein, and with the inferior vena cava by the ductus venosus.
F(ETAL Circulation.
The arterial blood destined for the nutrition of the foetus, is carried from the
placenta to the foetus, along the umbilical cord, by the umbilical vein. The
umbilical vein enters the abdomen at the umbilicus, and passes upwards along the
free margin of the suspensory ligament of the liver, to the under surface of this
organ, where it gives off two or three branches to the left lobe; and others to the
lobus quadratus and lobus Spigelii. At the transverse fissure, it divides into two
branches; of these, the larger joins the portal vein, and enters the right lobe: the
smaller branch continues onwards, under the name of the ductus venosus, and
joins the inferior vena cava. The blood, therefore, which traverses the umbilical
vein, reaches the inferior cava in three different ways. The greater quan-
tity circulates through the liver with the portal venous blood, before entering the
cava by the hepatic veins: some enters the liver directly, and is also returned to
the inferior cava by the hepatic veins: the smaller quantity passes directly into the
vena cava, by the ductus venosus.
In the inferior cava, the blood carried by the ductus venosus becomes mixed
with that returning from the lower extremities and viscera of the abdomen. It
enters the right auricle, and, guided by the Eustachian valve, passes through the
foramen ovale into the left auricle, where it becomes mixed with a small quantity
of blood returned from the lung by the pulmonaiy veins. From the left auricle
it passes into the left ventricle; and, from the left ventricle, into the aorta, from
whence it is distributed almost entirely to the head and upper extremities, a small
quantity being probably carried into the descending aorta. From the head and
upper extremities, the blood is returned by the branches of the superior vena cava
to the right auricle, where it becomes mixed with a small portion of the blood
from the inferior cava. From the right auricle, it descends over the Eustachian
valve into the right ventricle; and, from the right ventricle, into the pulmonary
artery. The lungs of the foetus being solid, and almost impervious, only a small
quantity of blood is distributed to them by the right and left pulmonary arteries,
which is returned by the pulmonary veins to the left auricle: the greater part
passes through the ductus arteriosus into the commencement of the descending
aorta, where it becomes mixed with a small quantity of blood transmitted by the
left ventricle into the aorta. Along this vessel it descends to supply the lower
extremities and viscera of the abdomen and pelvis, the chief portion being, how-
ever, conveyed by the umbilical arteries to the placenta.
From the preceding account of the circulation of the blood in the foetus, it will
be seen:
1. That the placenta serves the double purpose of a respiratory and nutritive
organ, receiving the venous blood from the foetus, and returning it again re-
oxygenated, and charged with additional nutritive material.
2. That nearly the whole of the blood of the umbilical vein traverses the liver
before entering the inferior cava; hence the enormous size of this organ, espe-
cially at an early period of foetal life.
3. That the right auricle is the point of meeting of a double current, the
640 THE THORAX.
blood in the inferior cava being guided by the Eustachian valve into the left
auricle, whilst that in the superior cava descends into the right ventricle. At an
early period of foetal life, it is highly probable that the two streams are quite
distinct; for the inferior cava opens almost directly into the left auricle, and the
Eustachian valve would exclude the current along the tube from entering the
right ventricle. At a later period, as the separation between the two auricles
becomes more distinct, it seems probable that some slight mixture of the two
streams must take place.
3. The blood carried from the placenta to the foetus by the umbilical vein,
mixed with the blood from the inferior cava, passes almost directly to the arch of
the aorta, and is distributed by the branches of this vessel to the head and upper
extremities ; hence the large size and perfect development of these parts at birth.
4. The blood contained in the descending aorta, chiefly derived from that
which has already circulated through the head and limbs, together with a small
quantity from the left ventricle, is distributed to the lower extremities; hence the
small size and imperfect development of these parts at birth.
Changes in the Vascular System at Birth.
At birth, when respiration is established, an increased amount of blood from
the pulmonary arteiy passes through the lungs, which now perform their office as
respiratory organs, and, at the same time, the placental circulation is cut off.
The foramen ovale becomes gradually closed in by about the tenth day after birth,
a valvular fold rises up on the left side of its margin, and ultimately above its
upper part; this valve becomes adherent to the margins of the foramen for the
greater part of its circumference, but above a valvular opening is left between the
two auricles, which sometimes remains persistent.
The ductus arteriosus begins to contract immediately after respiration is estab-
lished, becomes completely closed from the fourth to the tenth day, and ultimately
degenerates into an impervious cord, which serves to connect the left pulmonary
artery to the concavity of the arch of the aorta.
Of the umbilical or hypogastric arteries, their commencement forms the trunk
of the corresponding internal iliac; the portion continued on to the bladder
remains pervious, as the superior vesical artery; and the part between the fundus
of the bladder and the umbilicus becomes obliterated between the second and fifth
days after birth, and forms the anterior true ligament of this viscus.
The umbilical vein and ductus venosus become completely obliterated between
the second and fifth days after birth, and ultimately dwindle to fibrous cords; the
former becoming the round ligament of the liver, the latter, the fibrous cord,
which, in the adult, may be traced along the fissure of the ductus venosus to the
inferior cava.
Org-ans of Voice and Respiration.
The Larynx.
THE Larynx is the organ of voice, placed at tlie upper part of the air passage.
It is situated between the trachea and base of the tongue, at the upper and
fore part of the neck, wliere it forms a considerable projection in the middle line.
On either side of it lie the great vessels of the neck; behind, it forms part of
the boundary of the pharynx, and is covered by the mucous membrane lining this
cavity.
The larynx is narrow and cylindrical below, but broad above, where it presents
the form of a triangular box, being flattened behind and at the sides, whilst in
front it is bounded by a prominent vertical ridge. It is composed of cartilages,
connected together by ligaments, moved by numerous muscles, lined by mucous
membrane, and supplied with vessels and nerves.
The cartilages of the larynx are nine in number, three single and three pairs:
Thyroid.
Cricoid.
Epiglottis.
Two Arytenoid.
Two Cornicula Laryngis.
Two Cuneiform.
331. — Side View of the Thyroid and
Cricoid Cartilages.
The Thyroid {6vpeo<^ elSo'?, like a shield) is the largest cartilage of the
larynx. It consists of two lateral lamella? or alge, united at an acute angle
in front, forming a vertical projection in
the middle line, which is prominent above,
and called the pomum Adami. This pro-
jection is subcutaneous, more distinct in the
male than in the female, and occasionally
separated from the integument by a bursa
mucosa.
Each lamella is quadrilateral in form.
Its outer surface presents an oblique
ridge, which passes downwards and for-
wards from a tubercle, situated near the
root of the superior cornu. This ridge gives
attachment to the Sterno-thyroid and Thyro-
hyoid muscles; the portion of cartilage in-
cluded between it and the posterior border,
to part of the Inferior constrictor muscle.
The inner surface of each ala is smooth,
concave, and covered by mucous membrane
above and behind; but in front, in the re-
ceding angle formed by their junction, is
attached the epiglottis, the true and false
chordfe vocales, the Thyro-arytenoid, and
Thyro-epiglottidean muscles.
The upper border of the thyroid carti-
lage is deeply notched in the middle line,
immediately above the pomum Adami, whilst
' on either side it is slightly concave. This
border gives attachment throughout its Avhole extent to the thyro-hyoid mem-
brane.
The lower border is connected to the cricoid cnrtila^e, in the median line by
the crico-thyroid membrane, and on each side by the Crico-thyroid muscle.
TT
642
ORGANS OF VOICE AND RESPIRATION.
EPICLSSTTIS
The posterior borders, thick and rounded, terminate above in the superior
cornua, and below in the interior cornua. The two superior cornua are long and
narrow, directed backAvards, upwards, and inwards, and terminate in a conical
extremity, which gives attachment to the thyro-hyoid ligament. The two inferior
cornua are shorter and thicker; they pass forwards and inwards, and present, on
their inner surfaces, a small oval articular facet for articulation with the side of
the cricoid cartilage. The posterior border receives the insertion of the Stylo-
pharyngeus and Palato-pharyngeus muscles on each side.
The Cricoid Cartilage is so
332.— The Cartilages of the Larynx. called from its resemblance to
Posterior View. • 1. • r ■>^ tt.
a signet ring {KpiKo^-eioo^;, like
a ring). It is smaller but thicker
and stronger than the thyroid
cartilage, and forms the lower
and back part of the cavity of
the larynx.
Its anterior half is narrow,
convex, affording attachment in
front and at the sides to the
Crico-thyroid muscles, and be-
hind those to part of the Inferior
constrictor.
Its posterior half is very
broad, both from side to side
and from above downwards; it
presents in the middle line a
Vertical ridge for the attachment
of the longitudinal fibres of the
oesophagus; and on either side
of this is a broad depression for
the Crico-arytenoideus posticus
muscle.
At the point of junction of
the two halves of the cartilage
on either side, is a small round
elevation, for articulation with
the inferior cornu of the thyroid
cartilage.
The loioer border of the cri-
^■pytenoi.d Cart'.", liise "^ cold cai'tilagc Is horlzoutal, and
connected to the upper ring of
the trachea by fibrous membrane.
Its upper border is directed
obliquely upwards and back-
wards, owing to the great depth
of its posterior surface. It gives
attachment, in front, to the
crico-thyroid membrane; at the
sides, to part of the same mem-
brane and to the lateral Crico-
arytenoid muscle; behind, the highest point of the upper border is surmounted on
each side by a smooth oval surface, for articulation with the arytenoid cartilage.
Betv/een the articular surfaces is a slight notch, for the attachment of part of the
Arytenoideus muscle.
The inner surface of the cricoid cartilage is smooth, and lined by mucous
membrane.
The Arytenoid Cartilages are so called from the resemblance they bear, when
ARYTENO
CBICO-ARyT/ENOID
POST lets tT LATERALIS
/<..- Ir^fer. Cor
of TShyroie^
CARTILAGES OF LARYNX. 643
approximated, to the mouth of a pitcher {apvTaiva-elho^, like a pitcher). They
are two in number, and situated at the upper border of the cricoid cartilage, at
the back of the larynx. Eacli cartilage is pyramidal in form, and presents for
examination three surfaces, a base, and an apex.
The posterior surface is triangular, smooth, concave, and lodges part of the
Arytenoideus muscle.
The anterior surface, somewhat convex and rough, gives attachment to the
Thyro-arytenoid muscle, and to the false vocal cord.
The internal surface is narrow, smooth, and flattened, covered by mucous
membrane, and lies almost in apposition with the cartilage of the opposite side.
The base of each cartilage is broad, and presents a concave smooth surface, for
articulation with the cricoid cartilage. Of its three angles, the external one is
short, rounded, and prominent, receiving the insertion of the posterior and lateral
Crico-arytenoid muscles. The anterior one, also prominent, but more pointed,
gives attachment to the true vocal cord.
The apex of each cartilage is pointed, curved backwards and inwards, and
surmounted by a small conical- shaped, cartilaginous nodule, corniculum laryngis
(cartilage of Santorini). This cartilage is sometimes united to the arytenoid, and
serves to prolong it backwards and inwards. To it is attached the aryteno-
epiglottidean fold.
The Cuneiform Cartilages (cartilages of Wrisberg) are two small, elongated,
cartilaginous bodies, placed one on each side, in the fold of mucous membrane
which extends from the apex of the arytenoid cartilage to the side of the
epiglottis {aryteno-epiglottidean fold); they give rise to the small whitish eleva-
tions on the inner surface of the mucous membrane, just in front of the arytenoid
cartilages.
The Epiglottis is a thin lamella of fibro-cartilage, of a yellowish colour, shaped
like a leaf, and placed behind the tongue and in front of the superior opening of
the larynx. During respiration, its direction is vertically upwards, its free extre-
mity curving forwards towards +he base of the tongue; but when the larynx is
drawn up beneath the base of the tongue during deglutition, it is carried down-
wards and backwards, so as to completely close the opening of the larynx. Its
free extremity is broad and rounded; its attached end is long and narrow, and
connected to the receding angle between the two al^e of the thyroid cartilage,
just below the median notch, by a long, nai-row, ligamentous band, the thyro-
epiglottic ligament. It is also connected to the posterior surface of the body of
the hyoid bone, by an elastic ligamentous band, the hyo- epiglottic ligament.
Its anterior or lingual surface is curved forwards towards the tongue, and
covered by mucous membrane, which is reflected on to the sides and base of this
organ, forming a median and two lateral folds, the glosso-epiglottidean liga-
ments.
Its posterior or laryngeal surface is smooth, concave from side to side, convex
from above downwards, and covered by mucous membrane; when this is removed,
the surface of the cartilage is seen to be studded with a number of small mucous
glands, which are lodged in little pits upon its surface. To its sides the aryteno-
epiglottidean folds are attached.
Structure. The epiglottis, cuneiform cartilages, and cornicula laryngis are com-
posed of yellow cartilage, which shows little tendency to ossification; but the
other cartilages resemble in structure the costal cartilages, and they become more
or less ossified in old age.
Ligaments. The ligaments of the larynx are extrinsic, as those connecting the
thyroid cartilage with the os hyoides ; and intrinsic, as those connecting the
several cartilaginous segments to each other.
The ligaments connecting the thyroid cartilage with the os hyoides, are three
in number; the thyro-hyoidean membrane, and the two lateral thyro-hyoidean
ligaments.
The Thyro-hyoidean Membrane is a broad, fibro-elastic, membranous layer,
T T 2
644 OEGANS OF VOICE AND RESPIRATION.
attached below to the upper border of the thyroid cartilage, and above to the
upper border of the inner surface of the hyoid bone ; being separated from the
posterior surface of the hyoid bone by a synovial bursa. It is thicker in the
middle line than at either side, in which situation it is pierced by the superior
laryngeal nerve and artery.
The tivo lateral Thyr o-hyoidean Ligaments are rounded, elastic cords, which
pass between the superior cornua of the thyroid cartilage, to the extremities of
the greater cornua of the hyoid bone. A small cartilaginous nodule {cartilago
triticea), sometimes bony, is found in each.
The ligaments connecting the thyroid cartilage to the cricoid are also three in
number; the crico-thyroidean membrane, and the capsular ligaments and synovial
membrane.
The Crico-thyroid Membrane is composed mainly of yellow elastic tissue. It
is of triangular shape; thick in front, where it conriects together the contiguous
margins of the thyroid and cricoid cartilages ; thinner at each side, where it
extends from the superior border of the cricoid cartilage, to the inferior margin
of the true vocal cords, with which it is closely united in front.
The anterior portion of the crico-thyroid membrane is convex, concealed on
each side by the Crico-thyroid muscle, subcutaneous in the middle line, and crossed
horizontally by a small anastomotic arterial arch, formed by the junction of the
crico-thyroid branches on either side.
The lateral portions are lined internally by mucous membrane, and covered by
the lateral Crico-arytenoid and Thyro-arytenoid muscles.
A Capsular Ligament encloses the articulation of the inferior cornu of the
thyroid with the side of the cricoid, on each side. The articulation is lined
internally by synovial membrane.
The ligaments connecting the arytenoid cartilages to the cricoid, are two thin
and loose capsular ligaments connecting together the articulating surfaces, lined
internally by synovial membrane, and strengthened behind by a strong posterior
crico-arytenoid ligament, which extends from the cricoid to the inner and back
part of the base of the arytenoid cartilage.
The ligaments of the epiglottis are the hyo-epiglottic, the thyro-epiglottic, and
the three glosso-epiglottic folds of mucous membrane which connect the epiglottis
to the sides and base of the tongue. The latter have been already described.
The Hyo-epiglottic Ligament is an elastic fibrous band, Avhich extends from
the anterior surface of the epiglottis, near its apex, to the posterior surface of the
body of the hyoid bone.
The Thyro-epiglottic lAgament is a long, slender, elastic cord, which connects
the apex of the epiglottis with the receding angle of the thyroid cartilage, imme-
diately beneath the median notch, above the attachment of the vocal cords.
Interior of the Larynx. The superior aperture of the larynx is a triangular or
cordiform opening, wide in front, narrow behind, and sloping obliquely downwards
and backwards. It is bounded in front by the epiglottis; behind, by the apices
of the arytenoid cartilages, and the cornicula laryngis; and laterally, by a fold of
mucous membrane, enclosing ligamentous and muscular fibres, stretched between
the sides of the epiglottis and the apex of the arytenoid cartilage: these are the
aryteno-epiglottidean folds, on the margins of which the cuneiform cartilages
form a more or less distinct whitish prominence.
The cavity of the larynx is divided into two parts by the projection inwards of
the chordae vocales, and Thyro-arytenoid muscles; between the two cords is a
long and narrow triangular fissure or chink, the glottis, or rima glottidis. The
portion of the cavity of the larynx above the glottis, is broad and triangular in
shape above, and corresponds to the interval between the alse of the thyroid
cartilage; the portion below the glottis is at first elliptical, and lower down of a
circular fomn.
The glottis is the interval between the inferior vocal cords. The two superior
or false vocal cords are placed above the latter, and formed almost entirely by a
CAVITY OF LARYNX; GLOTTIS; VOCAL CORDS.
645
folding inwards of the raucous meinbnine; whilst the two inferior or true vocal
cords are thicic, strong, and formed partly by mucous membrane, and partly by
ligamentous fibres. Between the true and false vocal cords, on each side, is an
333.— Interior of the Larynx, seen from above
(eukrgod).
oval depression, the sinus or ve?itricle of the larynx, which leads upwards, on the
outer side of the superior vocal cord, into a ctecal pouch of variable size, the
sacculus laryngis.
Ihe Uima Glottidis is the narrow triangular fissure or chink between the infe-
rior or true chordae vocales. Its length, in the male, measures rather less than an
inch, its breadth varying at its widest part from a third to half an inch. In the
female, these measurements are less by two or three lines. The form of the
aperture varies; in ordinary respiration it is a narrow interval, being somewhat
enlarged and rounded behind; but when dilated, it is triangular in form, narrow
in front and broad behind.
The Superior or False Vocal Cords, so called because they are not concerned in
the production of the voice, are two thick folds of mucous membrane, enclosing a
delicate narrow fibrous band, the superior thyro-arytenoid ligament. This liga-
ment consists of a thin band of elastic tissue, attached in front to the receding
angle of the thyroid cartilage below the epiglottis, and behind to the tubercle on
the anterior and inner surface of the arytenoid cartilage. The lower border of
this ligament, enclosed in mucous membrane, forms a free crescentic margin, which
constitutes the upper boundary of the ventricle of the larynx.
The Inferior or True Vocal Cords, so called from their being concerned in
the production of sound, are two thick and strong fibrous bands {inferior thyro-
arytenoid ligaments^, covered externally by a thin and delicate mucous membrane.
Each ligament consists of a compact band of parallel fibres of yellow elastic tissue,
attached in front to the centre of the depression between the two alse of the
thyroid cartilage, and behind to the anterior angle of the base of the arytenoid.
Its inferior border is continuous with the thin lateral part of the crico-thyroid
membrane. Its superior border forms the lower boundary of the ventricle of the
larynx. Externally, the Thyro-arytenoideus muscle lies parallel with it. It is
64-6 ORGANS OF VOICE AND RESPIRATION.
covered internally by mucous membrane, which is extremely thin, and closely
adherent to its surface.
The Ventricle of the Larynx is an oblong fossa, situated between the superior
and inferior vocal cords on each side, and extending nearly their entire length.
This fossa is bounded above by the free crescentic edge of the superior vocal
cord; below, by the straight margin of the true vocal cord; externally, by the
corresponding Thyro-arytenoideus muscle. The anterior part of the ventricle
leads up by a narrow opening into a ceecal pouch of mucous membrane of variable
size, called the laryngeal pouch.
The Sacculus Laryngis, or laryngeal pouch, is a membranous sac, placed be-
tween the superior vocal cord and the inner surface of the thyroid cartilage,
occasionally extending as far as its upper border; it is conical in form, and curved
slightly backwards, resembling in form a Phrygian cap. On the surface of its
mucous membrane are the openings of sixty or seventy small follicular glands,
which are lodged in the submucous areolar tissue. This sac is enclosed in a
fibrous capsule, continuous below with the superior thyro-arytenoid ligament; its
laryngeal surface is covered by the Aryteno-epiglottideus inferior muscle {Com-
pressor sacculi laryngis, Hilton); whilst its exterior is covered by the Thyro-
epiglottideus mviscle. These muscles compress the sacculus laryngis, and discharge
the secretion it contains upon the chordae vocales, the surface of which it is in-
tended to lubricate.
Muscles. The intrinsic muscles of the larynx are eight in number; five of
which are the muscles of the chordaa vocales and rima glottidis; three are con-
nected with the epiglottis.
The five muscles of the chordae vocales and rima glottidis are the
Crico-thyroid. Arytenoideus.
Crico-arytenoideus posticus. Thyro-arytenoideus.
Crico-arytenoideus lateralis.
The Crico-thyroid is triangular in form and situated at the fore part and
side of the cricoid cartilage. It arises from the front and lateral part of the
cricoid cartilage; its fibres diverge, passing obliquely upwards and outwards, to
be inserted into the lower and inner borders of the thyroid cartilage; from near
the median line in front, as far back as the inferior cornu.
The inner borders of these two muscles are separated in the middle line by a
triangular interval, occupied by the crico-thyroid membrane.
The Crico-arytcBnoideus posticus arises from the broad depression occupying
each lateral half of the posterior surface of the cricoid cartilage; its fibres pass
upwards and outwards, and converge to be inserted into the outer angle of the
base of the arytenoid cartilage. The upper fibres are nearly horizontal, the
middle oblique, and the lower almost vertical.
The Crico-arytcenoideus lateralis is smaller than the preceding, and of an
oblong form. It arises from the upper border of the side of the cricoid cartilage,
and passing obliquely upwards and backwards, is inserted into the outer angle of
the base of the arytenoid cartilage, in front of the preceding muscle.
The Thyro-arytcenoideus is a broad flat muscle, which lies parallel with the
outer side of the true vocal cord. It arises in front from the lower half of the
receding angle of the thyroid cartilage, and from the crico-thyroid ligament. Its
fibres pass horizontally backwards and outwards, to be inserted into the base and
anterior and outer surface of the arytenoid cartilage. This muscle consists of two
fasciculi. The inferior, the thickest, is inserted into the anterior angle of the
base of the arytenoid cartilage, and into the adjacent portion of its anterior sur-
face; it lies parallel with the true vocal cord, to which it is occasionally adherent.
The superior fasciculus, the thinnest, is inserted into the anterior surface and
outer border of the arytenoid, above the preceding fibres; it lies on the outer
side of the sacculus laryngis, immediately beneath its mucous lining.
The Arytcenoideus is a single muscle, filling up the posterior concave surface of
MUSCLES OF LARYNX.
647
the arytenoid cartilages. It arises from the posterior surface and outer Lorder of
one arytenoid cartilage, and is inserted into the corresponding parts of the oppo-
site cartilage. It consists of three planes of fibres, two oblique and one transverse.
The oblique fibres, the most superli-
334. — Muscles of Larynx, side View.
Right Ala of Thyroid Cartilage removed.
cial, form two fasciculi, which pass
from the base of one cartilage to
the apex of the opposite one. The
transverse fibres, the deepest and most
numerous, pass transversely across
between the two cartilages; hence the
Arytenoideus was formerly considered
as several muscles, under the names of
transversi and obliqui. A few of the ob-
lique fibres are occasionally continued
round the outer margin of the cartilage,
and blend with the Thyro-arytenoid
or the Aryteno-epiglottidean muscle.
• The muscles of the epiglottis are the
Thyro-epiglottideus.
Arytfeno-epiglottideus superior.
Arytseno-epiglottideus inferior.
The Thyro-epiglottideus is a deli-
cate fasciculus, which arises from the
inner surface of the thyroid cartilage,
just external to the origin of the
Thyro-arytenoid muscle, and spread-
ing out upon the outer surface of the
sacculus laryngis, some of its fibres
are lost in the aryteno-epiglottidean
fold, whilst others are continued for-
wards to the margin of the epiglottis
{depressor epiglottidis).
The Arytceno-epiglottideus superior consists of a few delicate muscular fasciculi,
which arise from the apex of the arytenoid cartilage, and become lost in the fold
of mucous membrane extending between the arytenoid cartilage and side of the
epiglottis {aryteno-epiglottidean folds).
T\iQ Arytceno-epiglottideus inferior {Compressor sacculi laryngis, Hilton) arises
from the arytenoid cartilage, just above the attachment of the superior vocal cord,
and passing forwards and upwards, spreads out upon the inner and upper part of
the sacculus laryngis, and is inserted, by a broad attachment, into the margin of
the epiglottis. This muscle is separated from the preceding by an indistinct
areolar interval.
Actions. In considering the action of the muscles of the larynx, they may be
conveniently divided into two groups, viz.: I. Those which open and close the
glottis. 2. Those which regulate the degree of tension of the vocal cords.
I. The muscles which open the glottis are the Crico-arytajnoidei postici, and
those which close it are the Ary tajnoideus, the Crico-arytsenoidei laterales, and the
Thyro-arytainoidei. 2. The muscles which regulate the tension of the vocal cords
are the Crico-thyroidei, which tense and . elongate them, and the Thyro-arytas-
noidei, which relax and shorten them. The Thyro-epiglottideus is a depressor of
the epiglottis, and the Aryta3no-epiglotfcidei constrict the superior aperture of the
laiynx, compress the sacculus laryngis, and empty it of its contents.
The Crico-arytcenoidei postici separate the chorda3 vocales, and consequently
open the glottis, by rotating the base of the arytenoid cartilages outwards and
backwards; so that their anterior angles, and the ligaments attached to them,
become widely separated.
648 ORGANS OF VOICE AND RESPIRATION.
The Crico-arytcBJioidei laterales close the glottis, by rotating the base of the
arytenoid cartilages in the opposite direction to the last-named muscles, so as to
approximate their anterior angles.
The Arytcenoideus muscle approximates the arytenoid cartilages, and thus
closes the opening of the glottis.
The Crico-thyroid muscles effect the tension and elongation of the vocal cords.
The Thyro-aryteenoidei muscles approximate the anterior angles of the aryte-
noid cartilages, and thus constrict the glottis. According to Willis, they also
draw the arytenoid cartilages, together with the part of the cricoid to which
they are connected, forwards, and thus shorten and relax the vocal cords.
The Thyro-epiglottidei depress the epiglottis, and assist in compressing the
sacculus laryngis. The Aryteno-epiglottideus superior, constricts the superior
aperture of the larynx, when it is drawn upwards, during deglutition, and the
opening closed by the epiglottis. The Arytseno-epiglottideus inferior, together
with some fibres of the Thyro-aryta^noidei, compress the sacculus laryngis.
The Mucous Membrane of the Larynx is continuous, above, with that lining
the mouth and pharynx, and is prolonged through the trachea and bronchial tubes
into the lungs. It lines both surfaces of the epiglottis, to which it is closely
adherent, and forms the aryteno-epiglottidean folds, which encircle the superior
aperture of the larynx. It lines the whole of the cavity of the larynx; forms,
by its reduplication, the chief part of the superior, or false vocal cords ; and from
the ventricle is continued into the sacculus laryngis. It is then reflected over
the true vocal cords, where it is thin, and very intimately adherent; covers the
inner surface of the crico-thyroid membrane, and cricoid cartilage; and is ulti-
mately continuous with the lining membrane of the trachea. It is covered with
a columnar ciliated • epithelium, below the superior vocal cord, but, above this
point, the cilice are found only in front, as high as the middle of the epiglottis.
In the rest of its extent, the epithelium is of the squamous variety.
Glands. The mucous membrane of the larynx is furnished with numerous
muciparous glands, the orifices of which are found in nearly every part: they are
very numerous upon the epiglottis, being lodged in little pits in its substance:
they are also found in large numbers along the posterior margin of the aryteno-
epiglottidean fold, in front of the arytenoid cartilages, where they are termed the
arytenoid glands. They exist also in large numbers upon the inner surface of
the sacculus laryngis. None are found on the vocal cords.
The Arteries of the larynx are the laryngeal branches derived from the supe-
rior and inferior thyroid.
The Veins empty themselves into the superior, middle, and inferior thyroid
veins.
The Lymphatics terminate in the deep cervical glands.
The Nerves are the superior laryngeal, and the inferior or recurrent laryngeal
branches of the pneumogastric nerves, joined by filaments from the sympathetic.
The superior laryngeal nerve supplies the mucous membrane of the larynx, and
the Crico-thyroid muscle. The inferior laryngeal nerve supplies the remaining
muscles. The Arytenoid muscle is supplied by both nerves.
The Trachea.
The trachea, or air-tube, is a cartilaginous and membranous cylindrical tube,
flattened posteriorly, extending from the lower part of the larynx, on a level with
the fifth cervical vertebra, to opposite the third dorsal, where it divides into the
two bronchi, one for each lung. The trachea measures about four inches and a
half in length; its diameter, from side to side, is from three quarters of an inch
to an inch ; being always greater in the male than in the female.
Relations. The anterior surface of the trachea is convex, and covered, in
the neck, from above downwards, by the isthmus of the thyroid gland, the
inferior thyroid veins, the arteria thyroidea ima, (when that vessel exists),
TRACHEA.
649
the Sterno-hyoid and Sterno-thyroid muscles, the cervical fascia (in the in-
terval between these muscles), and, more superficially, by the anastomosing
branches between the anterior jugular veins: in the thorax, it is covered by
3 35-— Front View of Cartilages of Larynx : the Trachea and Bronchi.
the first piece of the sternum, the remains of the thymus gland, the left vena
innominata, the arch of the aorta, the innominate and left carotid arteries, and
the deep cardiac plexus. It lies upon the oesophagus, which is directed to
the left, near the arch of the aorta; later alii/, in the neck, it is in relation with
the common carotid arteries, the lateral lobes of the thyroid gland, the inferior
thyroid arteries, and recurrent laryngeal nerves; and, in the thorax, it lies in the
interspace between the pleurse.
The Right Bronchus, wider, shorter, and more horizontal in direction than the
left, is about an inch in length, and enters the right lung, opposite the fourth
dorsal vertebra. The vena azygos arches over it, from behind; and the right
pulmonary artery lies below, and then in front of It.
The Left Bronchus is smaller, more oblique, and longer than the right, being
650 ORGANS OF VOICE AND RESPIRATION.
nearly two inches in length. It enters the root of the left lung, opposite the
fifth dorsal vertebra, about an inch lower than the right bronchus. It crosses in
front of the oesophagus, the thoracic duct, and the descending aorta; passes
beneath the arch of the aorta, and has the left pulmonary artery lying at first
above, and then in front of it.
The trachea is composed of imperfect cartilaginous rings, fibrous membrane,
muscular fibres, longitudinal yellow elastic fibres, mucous membrane, and glands.
The Cartilages vary from sixteen to twenty in number: each forms an imper-
fect ring, which surrounds about two-thirds of the cylinder of the trachea, being
imperfect behind, where the tube is completed by fibrous membrane. The carti-
lages are placed horizontally above each other, separated by narrow membranous
intervals. They measure about two lines in depth, and half a line in thickness.
Their outer surfaces are flattened, but, internally, they are convex, from being
thicker in the middle than at the extremities. The cartilages are connected
together, at their margins, by an elastic fibrous membrane, which covers both
their surfaces; and in the space between their extremities, behind, forms a
distinct layer. The peculiar cartilages are the first and the two last.
The first cartilage is broader than the rest, and sometimes divided at one end:
it is connected by fibrous membrane with the lower border of the cricoid carti-
lage, with which, or with the succeeding cartilage, it is sometimes blended.
The last cartilage is thick and broad in the middle, in consequence of its lower
border being prolonged downwards, and, at the same time, curved backwards, at
the point of bifurcation of the trachea. It terminates on each side in an imper-
fect ring, which encloses the commencement of the bronchi. The cartilage above
the last, is somewhat broader than the rest at its centre. Two or more of the
cartilages often unite, partially or completely, and are sometimes bifurcated at
their extremities. They are highly elastic, and seldom ossify, even in advanced
life. In the right bronchus, the cartilages vary in number from six to eight; in
the left, from nine to twelve. They are shorter and narrower than those of
the trachea.
The Muscular Fibres are disposed in two layers, longitudinal and transverse.
The longitudinal fibres are the most external, and arise by minute tendons from
the termination of the tracheal cartilages, and from the fibrous membrane.
The transverse fibres, the most internal, form a thin layer, which extends
transversely between the ends of the cartilages, at the posterior part of the
trachea. The muscular fibres are of the involuntary class.
The Elastic Fibres are situated beneath the mucous membrane, enclosing the
entire cylinder of the trachea; they are most abundant at its posterior part,
where they are collected in longitudinal bundles.
The Tracheal Glands are found in great abundance at the posterior part of
the trachea. They are small, flattened, ovoid bodies, placed between the fibrous
and muscular coats, each furnished with an excretory duct, which opens on the
surface of the mucous membrane. Some glands of smaller size are also found at
the sides of the trachea, between the layers of fibrous tissue connecting the rin^s,
and others immediately beneath the mucous coat. The secretion from these
glands serves to lubricate the inner surface of the trachea.
The Mucous Membrane lining the tube is covered with columnar ciliated
epithelium. It is continuous with that lining the larynx.
Vessels and Nerves. The trachea is supplied with blood by the inferior thyroid
arteries.
The Veins terminate in the thyroid venous plexus.
The Nerves are derived from the pneumogastric and its recurrent branches,
and from the sympathetic.
Surgical Anatomy. The air-passage may be opened in three different situations ; through
the crico-thyroid membrane (laryngotomy), through the cricoid cartilage and upper ring
of the trachea {laryngo-tracheotomy), or through the trachea below the isthmus of the
SURGICAL ANATOMY OF LARYNGO-TRACHEAL REGION. 651
thyroid gland {tracheotomy'). The student should, therefore, carefully consider the relative
anatomy of the aix'-tube in each of these situations.
336. — Surgical Anatomy of Laryngo-Tracheal Kegion,
lu the Infant,
Orioo-tkyraid' ^MeinbraTic
St ^vtcvy
Cricocd CcJrtUagc
iSuupeTioT' T7iyroid' iKcn
Beneath the integument of the Kryngo-tracheal region, on either side of the median
line, are the two anterior jugular veins. Their size and position vary ; there is nearly
always one, and frequently two : at the lower part of the neck they diverge, passing
beneath the Sterno-mastoid muscles, and are frequently connected by a transverse com-
municating branch. These veins should, if possible, always be avoided in any operation
on the larynx or trachea. If cut through, considerable hsemorrhage is the result.
Beneath the cervical fascia are the Sterno-hyoid and Sterno-thyroid muscles, the conti-
guovis edges of the former being near the median line ; and beneath these muscles the
following parts are met with, from above downwards : the thyroid cartilage, the crico-
thyroid membrane, the cricoid cartilage, the trachea, and the isthmus of the thyroid
gland.
The crico-thyroid space is very superficial, and may be easily felt, beneath the skin, as a
depressed spot, about an inch below the pomum Adami ; it is crossed transversely by a
small artery, the crico-thyroid, the division of which is seldom accompanied by any
troublesome hsemorrhage.
The isthmus of the thyroid gland usually crosses the second and third rings of the
trachea ; above it, is found a large transverse communicating branch between the supe-
rior thyroid veins, and the isthmus is covered by a venous plexus, formed between the
thyroid veins of opposite sides. On the sides of the thyroid gland, and below it, the veins
converge to a single median vessel, or to two trunks which descend along the median line
of the front of the trachea, to open into the innominate vein by valved orifices. In the
infant, the thymus gland ascends a variable distance along the front of the trachea ; and
the innominate artery crosses this tube obliquely at the root of the neck, from left to
right. The arteria thyroidea ima, when that vessel exists, passes from below upwards along
the front of the trachea. The upper part of the trachea lies comparatively superficial ;
but the lower part passes obliquely downwards and backwards, so as to be deeply placed
between the converging Sterno-mastoid muscles. In the child, the trachea is smaller,
more deeply placed, and more moveable than in the adult. In fat, or short-necked peo-
ple, or in those in whom the muscles of the neck are prominently developed, the trachea
is more deeply placed than in the opposite conditions.
From these observations, it must be evident that laryngotomy is anatomically the most
simple operation, can most readily be performed, and should always be preferred when
particular circumstances do not render the operation- of tracheotomy absolutely neces-
sary. The operation is performed thus : The head being thrown back and steadied by an
652
ORGANS OF VOICE AND RESPIRATION.
assistant, the finger is passed over the front of the neck, and the crico-thyroid depression
felt for. A vertical incision is then made through the skin, in the middle line over this
spot, and the crico-thyroid membrane is divided to a sufiicient extent to allow of the
introduction of a large curved tube. The crico-thyroid artery is the only vessel of im-
portance crossing this space. If it should be of large size, its division might produce
troublesome hsemorrhage.
Laryngo-tracheotomy, anatomically considered, is more dangerous than tracheotomy, on
account of the small interspace between the cricoid cartilage and the isthmus of the
thyroid gland : the communicating branches between the superior thyroid veins, which
cover this spot, can hardly fail to be divided ; and the greatest care will not, in some
cases, prevent the division of part of the thyroid isthmus. If either of these structures is
divided, the hsemorrhage will be considerable.
Tracheotomy below the isthmus of the thyroid gland is performed thus : The head
being thrown back and steadied by an assistant, an incision, an inch and a half or two
inches in length, is made through the skin, in the median line of the neck, from a little
below the cricoid cartilage, to the top of the sternum. The anterior jugular veins should
be avoided, by keeping exactly in the median line ; the deep fascia should then be divided,
and the contiguous borders of the Sterno-hyoid muscles separated from each other. A
quantity of loose areolar tissue, containing the inferior thyroid veins, must then be sepa-
rated from the front of the trachea, with the handle of the scalpel ; and when the trachea
is well exposed, it should be opened by inserting the knife into it, dividing two or three
of its rings from below upwards. It is a matter of the greatest importance to restrain, if
possible, all hsemorrhage before the tube is opened ; otherwise, blood may pass into the
trachea, and suffocate the patient.
The Pleura.
Each lung is invested, upon its external surface, by an exceedingly delicate
serous membrane, the pleura, which encloses the organ as far as its root, and is
then reflected upon the inner surface of the thorax. The portion of the serous
337. — A Transverse Section of the Thorax, showing the relative Position of the Viscera,
and the Reflections of the Pleurse.
TRIANCUUARIS STERN
Infernal MamTnury 'Veaaels
Tiefi! F7ireiiu> Nerve
PleuftL fiulmonaUs
Pleura VastaUt
\ jSyxnpathefio N'ervR
I TTwracie Ductr
membrane investing the surface of the lung is called the pleura pulmonalis
(visceral layer of pleura) ; whilst that which lines the inner surface of the chest is
PLEURiE; MEDIASTINUM. 653
called the pleura costalis (parietal layer of pleura). The interspace or cavity
between these two layers is called the cavity of the pleura. Each pleura is
therefore a shut sac, one occupying the right, the other the left half of the thorax ;
and they are perfectly separate, not communicating with each other. The two
pleura3 do not meet in the middle line of the chest, excepting at one point in
front; an interspace being left between them, which contains all the viscera of
the thorax, excepting the lungs: this is the mediastinum.
Reflections of the Pleura (fig. 337). Commencing at the sternum, the pleura
passes outwards, covers the costal cartilages, the inner surface of the ribs and
Intercostal muscles, and at the back of the thorax passes over the thoracic
ganglia and their branches, and is reflected upon the sides of the bodies of the
vertebrae, where it is separated by a narrow interspace from the opposite pleura,
the posterior mediastinum.
From the vertebral column, the pleura passes to the side of the pericardium,
which it covers to a slight extent; it then covers the back part of the root of the
lung, from the lower border of which a triangular fold descends vertically by the
side of the posterior mediastinum to the Diaphragm. This fold is the broad
ligament of the lung, the lig amentum latum pulmonis, and serves to retain the
lower part of the organ in position. From the root, the pleura may be traced
over the convex surface of the lung, the summit and base, and also over the sides
of the fissures between the lobes. It covers its anterior surface, and front part
of its root, and is reflected upon the side of the pericardium to the inner surface
of the sternum.
Below, it covers the upper surface of the Diaphragm. Above, its apex pro-
jects, in the form of a cul-de-sac, through the superior opening of the thorax
into the neck, extending about an inch above the margin of the first rib, and
receives the summit of the corresponding lung: this sac is strengthened, according
to Dr. Sibson, by a dome-like expansion of fascia, derived from the lower part
of the Scaleni muscles.
A little above the middle of the sternum, the contiguous surfaces of the two
pleuriE are in contact for a slight extent; but above and below this point, the
interval left between them by their non- approximation forms the anterior medias-
tinum.
The inner surface of the pleura is smooth, polished, and moistened by a serous
fluid; its outer surface is intimately adherent to the surface of the lung, and to
the pulmonary vessels as they emerge from the pericardium; it is also adherent to
the upper surface of the Diaphragm; throughout the rest of its extent it is some-
what thicker, and may be separated from the adjacent parts with extreme facility.
The right pleural sac is shorter, wider, and reaches higher in the neck than the
left.
The arteries of the pleura are derived from the intercostal, the internal mam-
mary, the phrenic, inferior thyroid, thymic, pericardiac, and bronchial.
The veitis correspond to the arteries.
The lymphatics are very numerous.
The nerves are derived from the phrenic and sympathetic (Luschka). Kolliker
states that some accompany the ramifications of the bronchial arteries in the
pleura pulmonalis.
Mediastinum.
The mediastinum is the space left in the median line of the chest by the non-
approximation of the two pleura3. It extends from the sternum in front to the
spine behind, and contains all the viscera in the thorax, excepting the lungs.
The mediastinum may be subdivided, for convenience of description, into the
anterior, middle, and posterior.
The Anterior Mediastinum is bounded in front by the sternum, on each side by
the pleura, and behind by the pericardium. Owing to the oblique position of the
heart towards the left side, this space is not parallel with the sternum, but directed
654
ORGANS OF VOICE AND RESPIRATION.
obliquely from above downwards, and to the left of the median line; it is broad
below, narrow above, very narrow opposite the second piece of the sternum, the
contiguous surfaces of the two pleurae being occasionally united over a small
space. The anterior mediastinum contains the origins of the Sterno-hyoid and
Sterno-thyroid muscles, the Triangularis sterni, the internal mammary vessels of
the left side, the remains of the thymus gland, and a quantity of loose areolar
tissue, containing some lymphatic vessels ascending from the convex surface of
the liver.
The Middle Mediastinum is the broadest part of the interpleural space. It
contains the heart enclosed in the pericardium, the ascending aorta, the superior
vena cava, the bifurcation of the trachea, the pulmonary arteries and veins, and
the phrenic nerves.
The Posterior Mediastinum is an irregular triangular space, running parallel
with the vertebral column ; it is bounded in front by ^the pericardium and roots of
the lungs, behind by the vertebral column, and on either side by the pleura. It
contains the descending aorta, the greater and lesser azygos veins and superior
intercostal vein, the pneumogastric and splanchnic nerves, the oesophagus,
thoracic duct, and some lymphatic glands.
The Lungs.
The lungs are the essential organs of respiration; they are two in number,
338. — Front View of the Heart and Lungs.
Ducti s Arfcriosus
placed one in each of the lateral cavities of the chest, separated from each other
by the heart and other contents of the mediastinum. Each lung is conical in
LUNGS. 655
shape, and presents for examination an apex, a base, two borders, and two
surfaces.
The apex forms a tapering cone, which extends into the root of the neck,
about an inch to an inch and a half above the level of the first rib.
The base is broad, concave, and rests upon the convex surface of the Dia-
phragm; its circumference is thin, and fits into the space between the lower ribs
and the costal attachment of the Diaphragm, extending lower down externally
and behind than in front.
The external or thoracic surface is smooth, convex, of considerable extent,
and corresponds to the form of the cavity of the chest, being deeper behind than
in front.
The inner surface is concave. It presents, in front, a depression corresponding
to the convex surface of the pericardium, and behind, a deep fissure (the hilum
pulmonis), which gives attachment to the root of the lung.
The posterior border is rounded and broad, and is received in the deep con-
cavity on either side of the spinal column. It is much longer than the anterior
border, and projects below between the ribs and Diaphragm.
The anterior border is thin and sharp, and overlaps the front of the pericardium.
The anterior border of the right lung corresponds to the median line of the
sternum, and is in contact with its fellow, the pleurae being interposed, as low as
the fourth costal cartilage; below this, the contiguous borders are separated by a
V-shaped interval, formed at the expense of the left lung, and corresponding to
which the pericardium is exposed.
Each lung is divided into two lobes, an upper and lower, by a long and deep
fissure, which extends from the upper part of the posterior border of the organ,
about three inches from its apex, downwards and forwards to the lower part of
its anterior border. This fissure penetrates nearly to the root. In the right lung
the upper lobe is partially divided by a second and shorter fissure, which extends
forwards and upwards from the middle of the preceding to the anterior margin of
the organ, marking off a small triangular portion, the middle lobe. The left lung
presents a deep V-shaped notch at the lower part of its anterior border, into which
the apex of the heart is received.
The right lung is the largest; it is broader than the left, owing to the inclina-
tion of the heart to the left side; it is also shorter by an i-nch, in consequence of
the Diaphragm rising higher on the right side to accommodate the liver. The
right lung has also three lobes.
The left lung is smaller, narrower, and longer than the right, and has only
two lobes.
A little above the middle of the inner surface of each lung, and nearer its pos-
terior than its anterior border, is its root, by which the lung is connected to the
heart and the trachea. It is formed by the bronchial tube, the pulmonary artery,
the pulmonary veins, the bronchial arteries and veins, the pulmonary plexus of
nerves, lymphatics, bronchial glands, and areolar tissue, all of which are enclosed
by a reflection of the pleura. The root of the right lung lies behind the superior
cava and upper part of the right auricle, and below the vena azygos. That of the
left lung passes beneath the arch of the aorta, and in front of the descending aorta;
the phrenic nerve and the anterior pulmonary plexus lie in front of each, and
the pneumogastric and posterior pulmonary plexus behind each.
The structures composing the root of each lung are arranged in a similar
manner from before backwards on both sides, viz.: the pulmonary veins most
anterior; the pulmonary artery in the middle; and the bronchus, together with
the bronchial vessels, behind. From above downwards, on the two sides, their
. arrangement differs, thus:
On the right side, their position is, bronchus, pulmonary artery, pulmonary
veins; but on the left side, their position is, pulmonary artery, bronchus, pul-
monary veins; which is accounted for by the bronchus being placed on a lower
level on the left than on the rig-ht side.
656 ORGANS OF VOICE AND RESPIRATION.
The weight of both lungs together is about forty-two ounces, the right lung
being two ounces heavier than the left, but much variation is met with according
to the amount of blood or serous fluid they may contain. The lungs are heavier
in the male than in the female, their proportion to the body being, in the foi-mer,
as I to 37, in the latter, as I to 43. The specific gravity of the lung tissue varies
from 345 to 746, water being 1 000.
The colour of the lungs at birth is of a pinkish white; in adult life, mottled in
patches, of a dark slate colour; and, as age advances, this mottling assumes a
dark black colour. The colouring matter consists of granules of a carbonaceous
substance, deposited in the areolar tissue near the surface of the organ. It in-
creases in quantity as age advances, and is more abundant in males than in females.
The posterior border of the lung is usually darker than the anterior. The surface
of the lung is smooth, shining, and marked out into numerous polyhedral spaces,
which represent the lobules of the organ, and the area of each of these spaces is
crossed by numerous lighter lines.
The substance of the lung is of a light, porous, spongy texture; it floats in
water, and crepitates when handled, owing to the presence of air in the tissue;
it is also highly elastic; hence the collapsed state of these organs when they are
removed from the closed cavity of the thorax.
Structure. The lungs are composed of an external serous coat, a subserous
areolar tissue, containing a large proportion of elastic fibres, and the pulmonary
substance or parenchyma.
The serous coat is derived from the pleura; it is thin, transparent, and invests
the entire organ as far as the root.
The subserous areolar tissue contains a large proportion of elastic fibres; it
invests the entire surface of the lung, and extends inwards between the lobules.
The parenchyma is composed of lobules, which, although closely connected
together by an interlobular areolar tissue, are quite distinct from one another,
being easily separable in the foetus. The lobules vary in size; those on the sur-
face are large, of a pyramidal form, the base turned towards the surface; those in
the interior are smaller, and of various forms. Each lobule is composed of one
of the ramifications of the bronchial tube and its terminal air-cells, of the ramifi-
cations of the pulmonary and bronchial vessels, lymphatics, and nerves: all of these
structures being connected together by areolar fibrous tissue.
The bronchus upon entering the substance of the lung, divides and subdivides
dichotomously throughout the entire organ. Sometimes three branches arise
together, and occasionally small lateral branches are given off" from the sides of a
main trunk. Each of the smaller subdivisions of the bronchi enters a pulmonary
lobule (lobular bronchial tube), and again subdividing, ultimately terminates in
the intercellular passages and air-cells of which the lobule is composed. Within the
lungs the bronchial tubes are circular, not flattened, and their constituent elements
present the following peculiarities of structure.
The Cartilages are not imperfect rings, but consist of laminated plates, of
varied form and size, scattered irregularly along the sides of the tube, being most
distinct at the points of division of the bronchi. They may be traced into tubes
the diameter of which is only one-fourth of a line. Beyond this point, the tubes
are wholly membranous. The fibrous coat, and longitudinal elastic fibres, are
continued into the smallest ramifications of the bronchi. The muscular coat is
disposed in the form of a continuous layer of annular fibres, which may be traced
upon the smallest bronchial tubes: they consist of the unstriped variety of mus-
cular fibre. The mucous membrane lines the bronchi and its ramifications
throughout, and is covered with columnar ciliated epithelium.
According to the observations of Mr. Rainey,* the lobular bronchial tubes, on
entering the substance of the lobules, divide and subdivide from four to nine times,
according to the size of the lobule, continuing to diminish in size until they attain
* Medico-Chirugical Transactions, vol. xxviii. 1845.
STRUCTURE OF LUNG. 657
a diameter of 3^*^^ ^^ "3^0^^^ *^^ ^^ inch. They then become changed in structure,
losing their cylindrical form, and are continued onwards as irregular passages
(intercellular passages), through the substance of the lobule, their sides and
extremities being closely covered by numerous saccular dilatations, the air-cells.
This arrangement resembles most closely the naked eye appearances observed
in the reticulated structure of the lung of the tortoise, and other reptilia.
The air-cells are small, polyhedral, alveolar recesses, separated from each other
by thin septa, and communicating freely Avith the intercellular passages. They
are well seen on the sui'face of the lung, and vary from -n-^^th to -7^0*11 of an inch
in diameter; being largest on the surface, at the thin borders, and at the apex;
and smallest in the interior.
At the termination of the bronchial tubes, in the intercellular passages, their
constituent elements become changed: their walls are formed by an interlacing of
the longitudinal elastic bundles with fibrous tissue; the muscular fibres disappear,
and the mucous membrane becomes thin and delicate, and lined with a layer of
squamous epithelium. This membrane lines the air-cells, and forms by its redu-
plications the septa intervening between them.
The Pulmonary Artery, conveys the dark, impure venous blood to the lungs:
it divides into branches which accompany the bronchial tubes and terminate
in a dense capillary network upon the walls of the intercellular passages and air-
cells. From this network, the radicles of the pulmonary veins arise, coalescing
into large branches, they accompany the arteries, and return the blood, purified
by its passage through the capillaries, to the left auricle of the heart. In the
lung, the branches of the pulmonary artery are usually above and in front of a
bronchial tube, the vein below.
The Pulmonary Capillaries form plexuses which lie Immediately beneath the
mucous membrane, on the walls and septa of the air-cells, and upon the walls of
the intercellular passages. In the septa between the cells, the capillary network
forms a single layer. The capillaries are very minute, the meshes being only
slightly wider than the vessels: their walls are also exceedingly thin.
The Bronchial Arteries supply blood for the nutrition of the lung: they are
derived from the thoracic aorta, and, accompany the bronchial tubes, are
distributed to the bronchial glands, and upon the walls of the larger bronchial
tubes and pulmonary vessels, and terminate in the deep bronchial veins. Others
are distributed in the interlobular areolar tissue, and terminate partly in the
deep, partly in the superficial, bronchial veins. Lastly, some ramify upon the
walls of the smallest bronchial tubes, and terminate in the pulmonary veins.
The Superficial and Deep Bronchial Veins unite at the root of the lung, and
terminate on the right side in the vena azygos; on the left side, in the superior
intercostal vein.
The Lymphatics consist of a superficial and deep set: they terminate at the
root of the lung, in the bronchial glands.
Nerves. The lungs are supplied from the anterior and posterior pulmonary
plexuses, formed chiefly by branches from the sympathetic and pneumogastric.
The filaments from these plexuses accompany the bronchial tubes upon which
they are lost. Small ganglia have been found by Remak upon the smaller
branches of these nerves.
Thykoid Gland.
The thyroid gland bears much resemblance in structure to other glandular
organs, and is usually classified together with the thymus, supra-renal glands, and
spleen, under the head of ductless glands, from its possessing no excretory duct.
Its function is unknown, but, from its situation in connection with the trachea
and larynx, is usually described with these, although taking no part in the
function of respiration. It is situated at the upper part of the trachea, and
consists of two lateral lobes, placed one on each side of this tube, connected
together by a narrow transverse portion, the isthmus.
u u
658 ORGANS OF VOICE AND RESPIRATION.
Its anterior surface is convex, and covered by the Sterno-hyoid, Sterno-thyroid,
and Omo-hyoid muscles.
Its lateral surfaces, also convex, lie in contact with the sheath of the common
carotid artery.
Its posterior surface is concave, and embraces the trachea and larynx. The
posterior borders of the gland extend as far back as the lower part of the pharynx.
This gland is of a brownish red colour. Its weight varies from one to two
ounces. It is larger in females than in males, and becomes slightly increased in
size during menstruation. It occasionally becomes enormously hypertrophied,
constituting the disease called bronchocele, or goitre. Each lobe is somewhat
conical in shape, about two inches in length, and three-quarters of an inch in
breadth, the right lobe being rather the larger of the two.
The isthmus connects the lower third of the two lateral lobes: it measures
about half an inch in breadth, and the same in depth, and usually covers the
second and third rings of the trachea. Its situation presents, however, many
variations, a point of some importance in the operation of tracheotomy. Some-r
times the isthmus is altogether wanting.
A third lobe, of conical shape, called the pyramid, occasionally arises from the
left side of the upper part of the isthmus, or from the left lobe, and ascends as
high as the hyoid bone. It is occasionally quite detached, or divided into two
parts, or altogether wanting.
A few muscular bands are occasionally found attached, above, to the body of
the hyoid bone, and connected, below, with the isthmus of the gland, or its
pyramidal process, and named by Soemmering, the Levator glandulcB thyroidce.
Structure. The thyroid consists of numerous minute closed vesicles, com-
posed of a homogeneous membrane, enclosed in a dense capillary plexus, and
connected together into imperfect lobules by areolar tissue. These vesicles are
spherical or oblong, perfectly distinct, and contain a yellowish fluid, in which
are found floating numerous ' dotted corpuscles ' and cells. The fluid coa-
gulates by heat or alcohol, but preserves its transparency. In the foetus,
and in young subjects, the corpuscules lie in a single layer, in contact with
the inner surface of these cavities, and become detached during the process of
growth.
The Arteries supplying the thyroid, are the superior and inferior thyroid, and
sometimes an additional branch from the arteria innominata, which ascends from
this vessel upon the front of the trachea. The arteries are remarkable for their
large size and frequent anastomoses.
The Veins form a plexus on the surface of the glandj and on the front of the
trachea, from which arise the superior, middle, and inferior thyroid veins; the
two former terminating in the internal jugular, the latter in the vena inno-
minata.
The Lymphatics are numerous, of large size, and terminate in the thoracic and
right lymphatic ducts.
The Nerves are derived from the pneumogastric, and from the middle and
inferior cervical ganglia of the sympathetic.
Chemical Composition. The thyroid gland consists of albumen, traces of
gelatine, stearine, oleine, extractive matter, alkaline, and earthy salts, and water.
The salts are chloride of sodium, alkaline sulphate, phosphate of potash, lime,
magnesia, and a trace of oxide of iron.
Thymus Gland.
The thymus gland presents much resemblance in structure to other glandular
organs, and is classified under the head of the ductless glands, from its possessing
no excretory duct.
The thymus gland is a temporary organ, attaining its full size at the end of the
second year, when it ceases to grow, and gradually dwindles, until, at puberty, it
has almost disappeared. If examined when its growth is most active, it will be
THYROID AND THYMUS. 659
found to consist of two lateral lobes, placed in close contact along the middle line,
situated partly in the anterior mediastinum, partly in the neck, and extending
from the fourth costal cartilage upwards, as high as the lower border of the
thyroid gland. It is covered by the sternum, and by the origins of the Sterno-hyoid
and Sterno-thyroid muscles. In the mediastinum, it rests upon the pericardium,
being separated from the arch of the aorta and great vessels, by the thoracic
fascia. In the neck, it lies on the front and sides of the ti'achea, behind the Sterno-
hyoid and Sterno-thyroid muscles. The two lobes generally differ in size: they
are occasionally united, so as to form a single mass; and sometimes separated by
an intermediate lobe. The thymus is of a pinkish-grey colour, soft, and lobu-
lated on its surfaces. It is about two inches in length, one and half in width,
below, and about three or four lines in thickness. At birth, it weighs about half
an ounce.
Structure. Each lateral lobe is composed of numerous lobules, held together by
delicate areolar tissue; the entire gland being enclosed in an investing capsule of
a similar, but denser structure. The primary lobules vary in size from a pin's
head to a small pea. Each lobule contains in its interior a small cavity, which
is surrounded with smaller or secondary lobules, which are also hollow within.
The cavities of the secondary and primary lobules communicate; those of the
latter opening into the great central cavity, or reservoir of the thymus, which
extends through the entire length of each lateral half of the gland. The central
cavity is lined by a vascular membrane, which is prolonged into all the subordi-
nate cavities, and contains a milk-white fluid resembling chyle.
If the investing capsule and vessels, as well as the areolar tissue connecting
the lobules, are removed from the surface of either lateral lobe, it will be seen
that the central cavity is folded upon itself, and admits of being drawn out into a
lengthened tubular cord, around which the primary lobules are attached in a
spiral manner, like knots upon a rope. Such is the condition of the organ at an
early period of its development; for Mr. Simon has shown, that the primitive
form of the thymus is a linear tube, from which, as its development proceeds,
lateral diverticula lead outwards, the tube ultimately becoming obscure, from
its surface being covered with numerous lobules.
According to Oesterlen and Mr. Simon, the cavities in the secondary lobules
are surrounded by rounded saccular dilatations or vesicles, which open into it.
These vesicles are formed of a homogeneous membrane, enclosed in a dense
capillary plexus.
The whitish fluid contained in the vesicles and central cavity of the thymus,
contains numerous dotted corpuscles, similar to those found in the chyle. The
corpuscles are flattened circular discs, measuring about yoVo *^f ^^^ ^^*^^ ™ ^^^"
meter.
Chemical Composition. The solid animal constituents of the thymus are albu-
men and fibrine in large quantities, gelatine, and other animal matters. The salts
are alkaline and earthy phosphates, with chloride of potassium. It contains about
80 per cent of water.
The arteries supplying the thymus are derived from the internal mammary,
and from the superior and inferior thyroid.
The veins terminate in the left vena innominata, and in the thyroid veins.
The lymphatics are of large size, arise in the substance of the gland, and are
said to terminate in the internal jugular vein. Sir A. Cooper considered that
these vessels carried into the blood the secretion formed in the substance of the
thymus.
The nerves are exceedingly minute; they are derived from the pneumogastric
and sympathetic. Branches from the descendens noni and phrenic reach the
investing capsule, but do not penetrate into the substance of the gland.
u u 2
The Urinary Organs.
The Kidneys.
THE Kidneys are two glandular organs, intended for the secretion of the urine.
They are situated at the back part of the a,bdominal cavity, behind the
peritoneum, one in each lumbar region, extending from the eleventh rib to near
the crest of the ilium; the right one being lower than the left, from its vicinity
to the liver. They are usually surrounded by a considerable quantity of fat, and
are retained in their position by the vessels which pass to and from them.
Relations. The anterior surface of the kidney is convex, partially covered by
the peritoneum above, and is in relation, on the right side, with the liver,
descending portion of the duodenum, and ascending colon; and on the left side
with the great end of the stomach, the lower end of the spleen, and descending
colon.
The posterior surface is flattened, and rests upon the corresponding crus of the
Diaphragm, in front of the eleventh and twelfth ribs, on the anterior lamella of
the aponeurosis of the transversalis which separates it from the Quadratus
lumborum muscle, and on the Psoas magnus.
The superior extremity, directed inwards, is thick and rounded, and embraced
by the supra-renal capsule. It corresponds, on the left side, to the upper border
of the eleventh rib, and on the right side to the lower border.
The inferior extremity, small and flattened, extends nearly as low as the crest
of the ilium.
The external border is convex, and directed outwards towards the parietes of
the abdomen.
The internal border is concave, directed downwards and forwards, and presents
a deep notch, the hilus of the kidney, more marked behind than in front. At the
hilus, the vessels, excretory duct, and nerves pass into or from the organ; the
branches of the renal vein lying in front, the artery and its branches next, the
excretory duct or ureter being behind and below. The hilus leads into a hollow
space, the sinus, which occupies the interior of the gland.
Each kidney is about four inches in length, two inches in breadth, and about
one inch in thickness; the left one being somewhat longer and thinner than the
right. The weight of the kidney in the adult male varies from \\oz. to 6oz.;
in the female, from 40Z. to 5^02.; the difference between the two being about
half an ounce. The left is nearly always heavier than the right, by about
two drachms. Their weight in proportion to the body, is about i to 240. The
renal substance is dense, firi:^ extremely fragile, and of a deep red colour.
The kidney is invested by a proper fibrous capsule, formed of dense fibro-
areolar tissue. It is thin, smooth, and easily removed from its surface, to which
it is connected by fine fibrous processes and vessels; and at the hilus is continued
inwards, lining the sides of the sinus, and at the bottom of that cavity forms
sheaths around the blood-vessels, and the subdivisions of the excretory duct.
On making a vertical section through the organ, from its convex to its concave
border, it appears to consist of two different substances, named, from their posi-
tion, external or cortical, and internal or medullary, substance.
The cortical substance forms about three-fourths of the substance of the gland.
It occupies the surface of the kidney, forming a layer about two lines in thick-
KIDNEY.
66;
3 39- — Vertical Section of Kidney.
ness, and sends numerous prolongations inwards, towards the sinus between the
pyramids of the medullary substance.
The medullary substance consists of pale, reddish-coloured, conical masses, the
pyramids of Malpighi ; they vary in num-
ber from eight to eighteen; their bases are
directed towards the cortical substance ;
whilst their apices, which ai*e free, converge
towards the sinus, and are named the pa-
pillce (mammillaj) of the kidney. The kidney
is thus seen to consist of a number of coni-
cal-shaped masses, surrounded by an in-
vestment of the cortical substance : these
represent the separate lobules of which the
human kidney in the fcetus consists, a con-
dition observed permanently in the kid-
neys of many of the lower animals. As
the human kidney becomes developed, the
adjacent lobules coalesce, so as to form a
single gland, the surface of which, even in
the adult, occasionally presents faint traces
of a lobular subdivision.
The medullary portion is denser in struc-
ture than the cortical, and presents a striated
appearance, from being composed of a num-
ber of minute diverging tubes (tubuli uri-
niferi). The tubuli uriniferi commence at
the apices of the cones by small orifices,
which vary from
to
of an inch ;
340, — Minute Structure of Kidney.
as they pass up in the medullary sub-
stance, towards the periphery, they pursue
a diverging course, dividing and subdividing
at very acute angles, until they reach the
cortical substance, when they become convoluted, anastomose freely with
each other, and retain the same diameter. The number of orifices on the
entire surface of a single papilla is, according to Huschke, about a thousand;
from four to five hundred large, and as many smaller ones. The tubuli
uriniferi are formed of a transparent homogeneous basement membrane, lined
by spheroidal epithelium, which occupies about two-thirds of the diameter
of the tube. The tubes are separated from
one another, in the medullary cones, by
capillary vessels, which form oblong meshes
parallel with the tubuli, and by an interme-
diate parenchymatous substance composed
of cells.
The cortical substa?ice is soft, reddish,
granular, easily lacerated, and contains nu-
merous small, red, globular bodies dissemi-
nated through it in every part, excepting
towards the free surface. These are the
Malpighian bodies. The cortical portion,
like the tubular, is composed of the tubuli
uriniferi, blood-vessels, lymphatics, and
nerves, together with an intermediate pa-
renchymatous substance.
As soon as the tubuli uriniferi enter the
cortical substance (fig. 340), they become
convoluted, and anastomose freely with each other; they are sometimes called the
662 URINARY ORGANS.
tubes of Ferrein. At the bases of the pyramids, the straight tubes are described
as being collected into small conical fasciculi, the tortuous tubuli corresponding to
which are prolonged upwards into the cortical portion of the kidney as far as the
surface, forming a number of small conical masses, which are named the pyramids
of Ferrein, several of which correspond to each medullary confe and its corre-
sponding portion of cortical substance. According to Mr. Bowman, the tubuli
uriniferi commence in the cortical substance as small, dilated, membranous cap-
sules, the capsules of the Malpighian bodies; they also form loops, either by the
junction of adjacent tubes, or, according to Toynbee, by the union of two branches
proceeding from the same tube; they have also been seen to arise by free closed
extremities.
The Malfighian bodies are found only in the cortical substance of the kidney.
They are small rounded bodies, of a deep red colour-, and of the average diameter
of the Y^-Q of an inch. Each body is composed of a vascular tuft enclosed in a
thin membranous capsule, the dilated commencement of a uriniferous tubule.
The vascular tuft consists of the ramifications of a minute artery, the afferent
vessel, which, after piercing the capsule, divides, in a radiated manner, into
several branches, which ultimately terminate in a finer set of capillary vessels.
From these a small vein, the efferent vessel, proceeds; this j)ierces the capsule
near the artery, and forms a close venous plexus, with the efferent vessels from
other Malpighian bodies, around the adjacent tubuli.
The capsular dilatation of the Malpighian body is not always placed at the
commencement of the tube; it may occupy one side (Gerlach): hence their sub-
division into lateral or terminal. The membrane composing it is thicker than
that of the tubule; the epithelium lining its inner surface is thin, and in the
frog provided with cilia3 at the neck of the dilfj^ted portion; but in the human
subject, cilice have not been detected. According to Mr. Bowman, the surface of
the vascular tuft lies free and uncovered in the interior of its capsule; but accord-
ing to Gerlach, it is covered with a thick layer of nucleated cells, similar to those
lining the inner surface of the capsule.
Ducts. The ureter, as it approaches the hilus, becomes dilated into a funnel-
shaped membranous sac, the pelvis. It then enters the sinus, and subdivides
usually into three prolongations, the infundibula ; one placed at each extremity,
and one in the middle of the organ: these subdivide into smaller tubes, the calyces,
which surround, like a cup-like pouch or calyx, the bases of one or more of the
papillge. The ureter, the pelvis, and the calyces consist of three coats, fibrous,
muscular, and mucous.
The external ov fibro-elastic coat is continuous, around the bases of the papillge,
with the tunica propria investing the surface of the organ.
The muscular coat consists of a double layer of fibres placed between the
fibrous and mucous coats.
The internal or mucous coat invests the papillse of the kidney, and is continued
into the orifices upon their surfaces.
The Renal artery is large in proportion to the size of the organ which it
supplies. Each vessel divides into four or five branches, which enter the hilus,
and are invested by sheaths derived from the fibrous capsule; they penetrate the
substance of the organ between the papillje, and enter the cortical substance in
the intervals between the medullary cones; dividing and subdividing in their
course towards the bases of the pyramids, where they form arches by their anas-
tomoses : from these arches numierous vessels are distributed to the cortical
substance, some of which enter the Malpighian corpuscles; whilst others form a
capillary network around the uriniferous tubes.
The Veins of the kidney commence upon the surface of the organ, where they
have a stellate arrangement; they pass inwards, and open into larger veins, which
unite into arches around the bases of the medullary cones. After receiving the
venous plexus from the tubular portion, they accompany the branches of the
URETER; SUPRA-RENAL CAPSULE. 663
arteries to the sinus of the kidney, where they finally unite to form a single vein,
which terminjites in the inferior vena cava.
The hjmphatics of the kidney consist of a superficial and deep set; they accom-
pany the blood-vessels, and terminate in the lumbar glands.
The nerves are derived from the renal plexus, which is formed by filaments
from the solar plexus and lesser splanchnic nerve; they accompany the branches
of the arteries. From the renal plexus, some filaments pass to the spermatic
plexus and ureter.
The Ureters.
The Ureter is the excretory duct of the kidney. It is a cylindrical membra-
nous tube, from sixteen to eighteen inches in length, and of the diameter of a
goose-quill. It is placed at the back part of the abdomen, behind the peritoneum ;
and extends obliquely downwards and inwards, from the lower part of the pelvis
of the kidney, enters the cavity of the pelvis, and then passes downwards, for-
wards, and inwards, to the base of the bladder, into which it opens by a constricted
orifice, after passing obliquely, for nearly an inch, between its muscular and
mucous coats.
Relations. In its course from above downwards, it rests upon the Psoas
muscle, being covered by the peritoneum, and crossed in front very obliquely
by the spermatic vessels; the right ureter lying close to the outer side of the
inferior vena cava. Opposite the sacrum, it crosses the common iliac artery, or
the external iliac vessels, behind the ileum on the right side, and the sigmoid
flexure of the colon on the left. In the pelvis, it enters the posterior false liga-
ment of the bladder, runs below the obliterated hypogastric artery, the vas
deferens, in the male, passing between it and the bladder. In the female, the
ureter passes along the sides of the cervix uteri and upper part of the vagina.
At the base of the bladder, it is situated about two inches from its fellow;
lying, in the male, about an inch and a half behind the base of the prostate, at
the posterior angle of the trigone vesicae.
Structure. The ureter is composed of two coats, an external or muscular, and
an internal mucous coat.
The muscular coat consists of two layers of longitudinal fibres, and an inter-
mediate transverse layer.
The mucous coat is smooth, and presents a few longitudinal folds, which
become efifaced by distension. It is continuous with the mucous membrane of the
bladder below; whilst, above, it is prolonged over the papillae into the tubuli
uriniferi. The epithelial cells lining it are spheroidal.
The arteries supplying the ureter are branches of the renal, spermatic, internal
iliac, and inferior vesical.
The nerves are derived from the inferior mesenteric, spermatic, and hypo-
gastric plexuses.
Supra-Renal Capsules.
The supra-renal capsules are usually classified, together with the spleen,
thymus, and thyroid, under the head of ' ductless glands,' as they have no excre-
tory duct. They are two small flattened glandular bodies, of a yellowish colour,
situated at the back part of the abdomen, behind the peritoneum, immediately in
front of the upper end of either kidney; hence their name. The right one is
somewhat triangular in shape, bearing a resemblance to a cocked hat; the left is
more semilunar, and usually larger and higher than the right. They vary in size
in different individuals, being sometimes so small as to be scarcely detected; at
other times large. They measure from an inch and a quarter to nearly two
inches in length, about an inch and a quarter in breadth, and from two to three
lines in thickness. In weight, they vary from one to two drachms.
664 UEINARY ORGANS.
Relations. The anterior surface of the right supra-renal capsule is in relation
with the under surface of the liver; that of the left with the pancreas and
gpleen. The posterior surface rests upon the crus of the Diaphragm, opposite
the tenth dorsal vertebra. Their upper thin convex border is directed upwards
and inwards. Their lower thick concave border rests upon the upper end of the
kidneys, to which they are connected by the common investing areolar tissue.
Their inner borders are in relation with the great splanchnic nerves and semi-
lunar ganglia, and lie in contact on the right side with the inferior vena cava,
and on the left side with the aorta. The surface of the supra-renal gland is sur-
rounded by areolar tissue containing much fat, and closely invested by a thin
fibrous coat, which is difficult to remove, on account of the numerous fibrous and
vascular processes which enter the organ through the furrows on its anterior sur-
face and base.
Structure. On making a perpendicular section, the gland is seen to consist of
two substances, external or cortical, and internal medullary.
The cortical substance forms the chief part of the organ; it is of a deep yellow
colour, and consists of narrow columnar masses placed perpendicularly to the
surface.
The medullary substance is soft, pulpy, and of a dark brown or black colour;
hence the name, atrahiliary capsules, given to these organs. In its centre is
often seen a space formed by the breaking down of its component parts.
According to the researches of Oesterlen and Mr. Simon, the narrow columnar
masses of which the cortical substance is composed measure about yJ-Qth of an
inch in diameter, and consist of small closed parallel tubes of limitary membrane
containing dotted nuclei, together with much granular matter, oil globules, and
nucleated cells. According to Ecker, the apparent tubular canals consist of rows
of closed vesicles placed endwise, so as to resemble tubes; whilst Kolliker states,
that these vesicles are merely loculi or spaces in the stroma of the organ, having
no limitary membrane, and, from being situated endwise, present the appearance
of linear tubes. Nucleated cells exist in large numbers in the supra-renal
glands of ruminants, but more sparingly in man and other animals, but the
granular matter appears to form their chief constituent; their size varies, and they
present the singular peculiarity of undergoing no change when acted upon by
most chemical reagents. The columnar masses are surrounded by a close capil-
lary network, which runs parallel with them.
The medullary substance consists of nuclei and granular matter, uniformly
scattered throughout a plexus of minute veins.
The arteries supplying the supra-renal glands are numerous and of large
size, they are derived from the aorta, the phrenic, and the renal; they subdivide
into numerous minute branches previous to entering the substance of the gland.
The supra-renal vein returns the blood from the medullary venous plexus, and
receives several branches from the cortical substance; it opens on the right side
into the inferior vena cava, on the left side into the left renal vein.
The lymphatics terminate in the lumbar glands.
The nerves are exceedingly numerous; they are derived from the solar and
renal plexuses, and, according to Bergmann, from the phrenic and pneumo-
gastric nerves. They have numerous small ganglia developed upon them.
The Pelvis.
The cavity of the pelvis is that part of the general abdominal cavity which is
below the level of the linea ileo-pectinea and the promontory of the sacrum.
Boundaries. It is bounded, behind, by the sacrum, the coccyx, and the great
sacro-sciatic ligaments; in front and at the sides, by the pubes and ischia, covered
by the Obturator muscles; above, it communicates with the cavity of the abdomen;
and below, it is limited by the Levatores ani and Coccygei muscles, and the
BLADDER.
665
visceral layer of the pelvic fascia, which is reflected from the wall of the pelvis
on to the viscera.
Contents. The viscera contained in this cavity are the urinary bladder, the
lower end of the rectum, and the generative organs peculiar to each sex; they
are covered by the peritoneum, and supplied with blood and lymphatic vessels
and nerves.
The Bladder.
The bladder is the reservoir for the urine. It is a musculo-membranous sac,
situated in the pelvic cavity, behind the pubes, and in front of the rectum in the
male, the uterus and vagina intervening between it and that intestine in the
female. The shape, position, and relations of the bladder are greatly influenced
by age, sex, and the degree of distension of the organ. During infancy, it is
conical in shape, and projects above the upper border of the pubes into the hypo-
gastric region. In the adult, when quite empty and contracted, it is a small
341. — Vertical Section of Bladder, Penis, and Urethra.
FrapzLCb
triangular sac, placed deeply in the pelvis, flattened from before backwards, its
apex reaching as high as the upper border of the symphysis pubis. When
slightly distended, it has a rounded form, and partially fills the pelvic cavity; and
when greatly distended, is ovoid in shape, rising into the abdominal cavity, often
extending upwards nearly as high as the umbilicus. It is larger in its vertical
diameter than from side to side, and its long axis is directed from above obliquely
downwards and backwards in a line directed from some point between the pubes
and umbilicus (according to its distension) to the coccyx. The bladder, when
distended, is slightly curved forwards towards the anterior wall of the abdomen,
666 URINARY ORGANS.
so as to be more convex behind than in front. In tlae female, it is larger in the
transverse than in the vertical diameter, and its capacity is said to be greater
than in the male. The ordinary amount which it contains is about a pint.
The bladder is divided into a summit, body, base, and neck.
The summit, or apex, of the bladder is rounded and directed forwards and up-
wards; it is connected to the umbilicus by a iibro-muscular cord, the urachus, and
also by means of two rounded fibrous cords, the obliterated portions of the hypo-
gastric arteries, which are placed one on each side of the urachus.
The urachus is the obliterated remains of a tubular canal existing in the em-
bryo, which connects the cavity of the bladder with a membranous sac placed
external to the abdomen, opposite the umbilicus, called the allantois. In the
infant at birth, it is occasionally found pervious, so that the urine escapes at the
umbilicus, and calculi have been found in its canal.. The summit of the bladder
behind the urachus is covered by peritoneum, whilst the portion in front is
uncovered by it, and rests upon the abdominal wall.
The body of the bladder in front is not covered by peritoneum, and is in rela-
tion with the triangular ligament of the urethra, the posterior surface of the
symphysis pubis, the Internal obturator ' muscles, and, when distended, with the
abdominal parietes.
The posterior surface is covered by peritoneum throughout. It corresponds, in
the male, with the rectum; in the female, with the uterus, some convolutions of
the small intestines being interposed.
The side of the bladder is crossed obliquely from below, upwards and for-
wards, by the obliterated hypogastric artery: above and behind this cord, the
bladder is covered by peritoneum; but, below and in front of it, the serous cover-
ing is wanting, and it is connected to the pelvic fascia. The vas deferens passes,
in an arched direction, from before backwards, along the side of the bladder, to-
wards its base, crossing in its course the obliterated hypogastric artery, and
passing along the inner side of the ureter.
The base of the bladder is broad, directed downwards and backwards, and
rests, in the male, upon the second portion of the rectum, from which it is
separated by a reflection of the recto- vesical fascia. It is covered posteriorly,
for a slight extent, by the peritoneum, which is reflected from it upon the
rectum, forming the recto-vesical fold. The portion of the bladder in relation
with the rectum, corresponds to a triangular space, bounded behind by the recto-
vesical peritoneal fold; on either side, by the vesicula seminalis and vas deferens;
and in front, by the prostate gland. In the female, the base of the bladder is
adherent to the anterior wall of the vagina, and separated from the lower part
of the anterior surface of the cervix uteri, by a fold of the peritoneum.
The cervix, or neck of the bladder, is the constricted portion continuous with
the urethra. In the male, its direction is oblique in the erect posture, and it is
surrounded by the prostate gland. In the female, its direction is obliquely down-
wards and forwards.
Ligaments. The bladder is retained in its place by ligaments, which are
divided into true and false. The true ligaments are five in number, two ante-
rior, and two lateral, formed by the recto-vesical fascia, and the urachus. The
false ligaments, also five in number, are formed by folds of the peritoneum.
The Anterior, or Pubo-prostatic Ligaments, extend from the back of the
pubes, one on each side of the symphysis, to the front of the neck of the
bladder, and upper surface of the prostate gland. In the interval between the
two, passes the dorsal vein of the penis. These ligaments contain a few muscular
fibres, prolonged from the bladder.
The Lateral Ligaments, broader and thinner than the preceding, are formed
by reflected portions of the visceral layer of the pelvic fascia, which are attached
to the lateral parts of the prostate, and to the sides of the base of the bladder.
The Urachus is the fibro-muscular cord already mentioned, extending between
STRUCTURE OF BLADDER. 667
the apex of the bladdex' and the umbilicus. It is broad below, at its attachment
to the bladder, and becomes narrower as it ascends.
The False Ligaments of the bladder are formed by peritoneum: they are five
in number, two posterior, two lateral, and one superior.
The two posterior pass forwards, in the male, from the sides of the rectum; in
the female, from the sides of the uterus, to the posterior and lateral aspect of the
bladder: they foi-m the lateral boundaries of the recto- vesical fold of peritoneum,
and contain the obliterated hypogastric arteries, the ureters, and vessels and
nerves.
The tivo lateral ligaments are reflections of the peritoneum, from the iliac
fossae to the sides of the bladder.
The superior ligament is the prominent fold of peritoneum extending from the
summit of the bladder to the umbilicus. It covers the urachus, and the oblite-
rated hypogastric arteries.
Structure. The bladder is composed of four coats: a serous, a muscular, a
cellular, and a mucous coat.
The serous coat is partial, and derived from the peritoneum. It invests the
posterior surface, from opposite the termination of the two ureters to its summit,
and is reflected from this point and from the sides, on to the abdominal and
pelvic walls.
The muscular coat consists of two layers of unstriped muscular fibre, an
external layer, composed of longitudinal fibres, and an internal layer of circular
fibres.
The longitudinal fibres are most distinct on the anterior and posterior surfaces
of the organ. They arise, in front, from the anterior ligaments of the bladder
from the neck of the bladder, and, in the male, from the adjacent portion of the
prostate gland. They spread out, and form a plexiform mesh, on the anterior
surface of the bladder, being continued over the posterior surface and base of
the organ to the neck, where they are inserted into the prostate, in the male,
and into the vagina in the female.
Other longitudinal fibres arise, in the male, from the sides of the prostate, and
spread out upon the sides of the bladder, intersecting with one another.
The circular fibres are very thinly and irregularly scattered on the body of
the organ; but, towards its lower part, around the cervix and commencement of
the urethra, they are disposed in a thick circular layer, forming the sphincter
vesica.
Two bands of oblique fibres, originating behind the orifices of the ureters,
converge to the back part of the prostate gland, and are inserted, by means of a
fibrous process, into the middle lobe of this organ. They are the muscles of the
ureters, described by Sir C. Bell, who supposed that, during the contraction of
the bladder, they served to retain the oblique direction of the ureters, and so
prevent the reflux of urine into them.
The cellular coat consists of a layer of areolar tissue, connecting together the
muscular and mucous coats, being intimately connected with the latter.
The mucous coat is thin, smooth, and of a pale rose colour. It is
continuous through the ureters with the lining membrane of the uriniferous
tubes, and below, with the urethra. It is connected loosely to the muscular coat,
by a layer of areolar tissue, excepting at the trigone, where its adhesion
is more close. It is provided with a few mucous follicles; and numerous small
racemose glands, lined with columnar epithelium, exist near the neck of the
organ. The epithelium covering it is intermediate in form between the columnar
and squamous varieties.
Interior of the bladder. Upon the internal surface of the base of the bladder,
immediately behind the urethral orifice, is a triangular, smooth surface, the apex
of which is directed forwards: this is the trigonum vesicce, or trigone vesicate.
It is paler in colour than the rest of the mucous membrane, and never presents
668
UBINARY ORGANS.
any rugse, even in the collapsed condition of the organ, owing to its intimate
adhesion to the subjacent tissues. It is bounded on each side by two slight
ridges, which pass backwards and outwards to the orifices of the ureters, and
correspond with the muscles of these tubes; at each posterior angle, are the orifices
of the ureters, which are placed nearly two inches from each other, and about an
inch and a half behind the orifice of the urethra. Projecting from the lower and
anterior part of the bladder, into the orifice of the urethra, is a slight elevation
of mucous membrane, called the uvula vesicce. It is formed by a thickening of the
submucous areolar tissue, and lies just in front of the middle lobe of the
prostate.
The Arteries supplying the bladder are the superior, middle, and inferior
vesical, in the male, with additional branches from the uterine, in the female.
They are all derived from the anterior trunk of the mternal iliac.
The Veins form a complicated plexus around the neck, sides, and base of the
bladder, and terminate in the internal iliac vein.
The Lymphatics accompany the
34-2. — The Bladder and Urethra laid open.
Seen from above.
blood-vessels, passing through the
glands surrounding them.
The Nerves are derived from the
hypogastric and sacral plexuses; the
former supplying the upper part of
the organ, the latter its base and
neck.
Male Urethka.
The urethra extends from the neck
of the bladder to the meatus urinarius.
It is curved in its course, so as to
resemble, in its flaccid state, the italic
letter f; but in the erect state it
forms only a single curve, the con-
cavity of which is directed upwards.
Its length varies from eight to nine
inches ; and it is divided into three
portions, the prostatic, membranous^
and spongy, the structure and rela-
tions of which are essentially differ-
ent.
The Prostatic portion is the widest
and most dilatable part of the canal.
It passes through the prostate gland,
from its base to its apex, lying nearer
its upper than its lower surface. It
is about an inch and a quarter in
length; and the form of the canal is
spindle-shaped, being wider in the
middle than at either extremity, and
narrowest in front, where it joins the
membranous portion. A transverse
section of the canal in this situation
is triangular, the apex directed down-
wards.
Upon the floor of the canal is a
narrow longitudinal ridge, the veru
montanum, or caput gallinaginis,
formed by an elevation of the mucous membrane and its subjacent tissue. It is
Qrtfiees ttf duets.
URETHRA. 669
eight or nine lines in length, and a line and a half in height ; and contains,
according to Kobelt, muscular and erectile tissues. When distended, it may serve
to prevent the passage of the semen backwards into the bladder. On each side
of the ridge is a slightly depressed fossa, the prostatic sinus, the floor of which is
perforated by numerous apertures, the orifices of the prostatic ducts, the ducts of
the middle lobe opening behind the crest. At the fore part of the verumonta-
num, in the middle line, is a depression, the sinus pocularis {vesicula prostatica);
and upon or within its margin are the slit-like openings of the ejaculatory ducts.
The sinus pocularis forms a cul-de-sac about a quarter of an inch in length,
which runs upwards and backwards in the substance of the prostate, beneath the
middle lobe; its prominent upper wall partly forms the veru montanum. Its walls
are composed of fibrous tissue, muscular fibres, and mucous membrane ; and
numerous small glands open on its inner surface. It has been called by Weber,
who discovered it, the uterus masculinus, from its supposed homology with the
female organ.
The Membranous portion of the urethra extends between the apex of the
prostate, and the bulb of the corpus spongiosum. It is the narrowest part of the
canal (excepting the orifice), and measures three-quarters of an inch along its
upper, and half an inch along its lower surface, in consequence of the bulb pro-
jecting backwards beneath it below. Its upper concave surface is placed about an
inch beneath the pubic arch, from which it is separated by the dorsal vessels and
nerves of the penis, and some muscular fibres. Its lower convex surface is sepa-
rated from the rectum by a triangular space, which constitutes the perin^eum.
The membranous portion of the urethra perforates the deep perineal fascia; and
two layers from this membrane are prolonged around it, the one forwards, the
other backwards; it is also surrounded by the Compressor urethras muscle. Its
coverings are mucous membrane, elastic fibrous tissue, a thin layer of erectile
tissue, muscular fibres, and a prolongation from the deep perineal fascia.
The Spongy portion is the longest part of the urethra, and is contained in the
corpus spongiosum. It is about six inches in length, and extends from the ter-
mination of the membranous portion to the meatus urinarius. Commencing
below the symphysis pubis, it ascends for a short distance, and then curves down-
wards. It is narrow and of uniform size in the body of the penis, measuring
about a quarter of an inch in diameter; being dilated behind, within the bulb,
where it forms the bulbous portion; and again anteriorly, within the glans penis,
forming the fossa navicularis. A cross section of this canal in the body has its
diameter transverse; but in the glans the diameter is directed vertically.
The meatus urinarius is the most contracted part of the urethra; it is a verti-
cal slit, about three lines in length, bounded on each side by two small labia.
The inner surface of the lining membrane of the urethra, especially on the floor of
the spongy portion, presents the orifices of numerous mucous glands and follicles,
situated in the submucous tissue, and named the glands of Littre. They vary in
size, and their orifices are directed forwards; so that they may easily intercept
the point of a catheter in its passage along the canal. One of these lacunae,
larger than the rest, is situated on the upper surface of the fossa navicularis,
about an inch and a half from the orifice; it is called the lacuna magna. Into
the bulbous portion are found opening the ducts of Cowper's glands.
Structure. The urethra is composed of three coats, a mucous, muscular,
and erectile.
The mucous coat forms part of the genito-urinary mucous membrane. It is
continuous with the mucous membrane of the bladder, ureters, and kidneys ;
externally with the integument covering the glans penis; and is prolonged into
the ducts of the numerous glands which open into the urethra, viz. Cowper's
glands, the prostate gland, and through the ejaculatory ducts is continued into
the vasa deferentia and vesicul^e seminales. In the spongy and membranous
portions, the mucous membrane is arranged in longitudinal folds when the organ
is contracted. Small papillfe are found upon it, hear the orifice; and its epithe-
670 URINARY ORGANS.
Hal lining is of the columnar variety, excepting near the meatus, where it is
laminated.
The muscular coat consists of two layers of plain muscular fibres, an external
longitudinal layer, and an internal circular. The muscular tissue is most
abundant in the prostatic portion of the canal.
A thin layer of erectile tissue is continued from the corpus spongiosum around
the membranous and prostatic portions of the urethra to the neck of the bladder.
Hale Generative Ora^ans.
Prostate Gland.
THE Prostate Gland (Trpoiarrj/Jbt, to stand before) is a pale, firm, glandular body,
which surrounds the neck of the bladder and commencement of the urethra.
It is placed in the pelvic cavity, behind and below the symphysis pubis, posterior
to the deep perina3al fascia, and upon the rectum, through which it may be dis-
tinctly felt, especially when enlarged. In shape and size it resembles a horse-
chesnut.
Its base is directed backwards towards the neck of the bladder.
The apex is directed forwards to the deep perinasal fascia, which it touches.
Its under surface is smooth, and rests on the rectum, to which it is connected
by a dense areolar fibrous tissue.
Its upper surface is flattened, marked by a slight longitudinal furroAV, and
placed about three-quarters of an inch below the pubic symphysis.
It measures about an inch and a half in its transverse diameter at the base, an
inch in its anterior posterior, and three-quarters of an inch in depth; and its
weight is about six drachms. It is held in its position by the anterior ligaments
of the bladder {pubo prostatic) ; by the posterior layer of the deep perinaeal fascia,
which invests the commencement of the membranous portion of the urethra and
prostate gland; and by the anterior portion of the Levator ani muscle {levator
prostatce), which passes down on each side from the symphysis pubis and anterior
ligament of the bladder to the convex sides of the prostate.
The prostate consists of three lobes; two lateral and a middle lobe.
The tico lateral lobes are of equal size, separated behind by a deep notch, and
marked by a slight furrow upon their upper and lower surface, which indicates
the bi-lobed condition of the organ in some animals.
The third or middle lobe is a small transverse band, occasionally a rounded or
triangular prominence, placed between the two lateral lobes at the under and pos-
terior part of the organ. It lies immediately beneath the neck of the bladder,
behind the commencement of the urethra, and above the ejaculatory ducts. Its
existence is not constant, but it is occasionally found at an early period of life, as
well as in the adults, and in old age. In advanced life it often becomes enlarged
and projects into the bladder, so as to impede the evacuation of the urine.
The prostate gland is perforated by the urethra and common seminal ducts.
The urethra usually lies about one-third nearer its upper than its lower surface;
occasionally the prostate surrounds only the lower three-fourths of this tube, and
it more rarely runs through the lower than the upper part of the gland. The
ejaculatory ducts pass forwards obliquely through a conical canal, situated in the
lower part of the prostate, and open into the prostatic portion of the urethra.
Structure. The prostate is enclosed in a thin but firm fibrous capsule, distinct
from that derived from the posterior layer of the deep perinasal fascia, and sepa-
rated from it by a plexus of veins. Its substance is of a pale reddish grey colour,
very friable, but of great density. It consists of glandular substance and mus-
cular tissue.
The glandular substance is composed of numerous follicular pouches, opening
into elongated canals, which join to form from twelve to twenty small excretory
ducts. The follicles are connected together by areolar tissue, supported by pro-
longations from the fibrous capsule, and enclosed in a delicate capillary plexus.
The epithelium lining the canals is columnar, whilst that in the terminal vesicles
is of the squamous variety.
The muscular tissue of the prostate is arranged in the form of circular
672 MALE GENERATIVE ORGANS.
bands around the urethra; it is continuous behind with the circular fibres of the
sphincter vesicae, and in front with the circular fibres of the urethra. The
muscular fibres are of the involuntary kind. The prostatic ducts open into the
floor of the prostatic portion of the urethra.
Vessels and Nerves. The arteries supplying the prostate are derived from the
internal pudic, vesical, and hasmorrhoidal. Its veins form a plexus around the
sides and base of the gland; they communicate in front with the dorsal vein of
the penis, and terminate in the internal iliac vein. The nerves are derived from
the hypogastric plexus.
The Prostatic Secretion is a milky fluid, having an acid reaction, and presenting
on microscopic examination, molecular matter, the squamous and columnar forms
of epithelium, and granular nuclei. In old age, this gland is liable to be enlarged,
and its ducts are often filled with innumerable small concretions, of a brownish
red colour, and of the size of a millet seed, composed of carbonate of lime and
animal matter.
Cowper's Glands.
Cowper's Glands are two small rounded and somewhat lobulated bodies, of a
yellowish colour, about the size of peas, placed beneath the fore-part of the
membranous portion of the urethra, between the two layers of the deep perinseal
fascia. They lie close behind the bulb, and are enclosed by the transverse fibres
of the Compressor urethras muscle. Each gland consists of several lobules, held
together by a fibrous investment. The excretory duct of each gland, nearly an
inch in length, passes obliquely forwards beneath the mucous membrane, and
opens by a minute orifice on the floor of the bulbous portion of the urethra.
Their existence is said to be constant; they gradually diminish in size as age
advances.
The Penis.
The penis is the organ of copulation, and contains in its interior the larger
portion of the urethra. It consists of a root, body, and the extremity or glans
penis.
The roof is broad and firmly connected to the rami of the pubes by two strong
tapering fibrous processes, the crura, and to the front of the symphysis pubis by
a fibrous membrane, the suspensory ligament.
The extremity or glans penis presents the form of an obtuse cone, flattened
from above downwards. At its summit is a vertical fissure, the orifice of the
urethra (meatus urinarius); and at the back part of this orifice a fold of mucous
membrane passes backwards to the bottom of a depressed raphe, where it is con-
tinuous with the prepuce; this fold is termed the frcenum preputii. The base of
the glans forms a rounded projecting border, the corona glandis; and behind the
corona is a deep constriction, the cervix. Upon both of these parts numerous
small lenticular sebaceous glands are found, the glandulce Tysonii, odoriferce.
They secrete a sebaceous matter of very peculiar odour, which probably contains
caseine, and becomes easily decomposed.
The body of the penis is the part between the root and the extremity. In the
flaccid condition of the organ it is cylindrical, but when erect has a triangular
prismatic form with rounded angles, the broadest side being turned upwards, and
called the dorsum. It is covered by integument remarkable for its thinness, its
dark colour, its looseness of connection with the deeper parts of the organ, and
for containing no adipose tissue. At the root of the penis it is continuous with
that upon the pubes and scrotum; and at the neck of the glans it leaves the sur-
face, and becomes folded upon itself to form the prepuce.
The internal layer of the prepuce, which also becomes attached to the cervix,
approaches in character to a mucous membrane; it is reflected over the glans
penis, and at the meatus urinarius is continuous with the mucous lining of the
urethra.
r
PENIS. 673
The mucous membrane covering the glans penis contains no sebaceous glands,
but upon it are a number of small papillary elevations, which are highly sensitive.
The penis is composed of a mass of erectile tissue, enclosed in three cylindrical
fibrous compartments. Of these, two, the corpora cavernosa, are placed side by
side along the upper part of the organ; the third, or corpus spongiosum, encloses
the urethra, and is placed below.
The Corpora Cavernosa form the chief part of the body of the penis. They
consist of two cylindrical fibrous portions, placed side by side, and intimately
connected along the median line for their anterior three-fourths, their posterior
fourth being separated to form the two crura, by which the penis is connected to
the rami of the pubes. Each crus commences by a thick-pointed process in front
of the tubei-osity of the ischium; and near its junction with its fellow, presents
a slight enlargement, named by Kobelt, the bulh of the corpus cavernosum. Just
beyond this point they become constricted, and retain an equal diameter to their
anterior extremity, where they form a single rounded extremity, which is received
into a fossa in the base of the glans penis. A median groove on the upper sur-
face lodges the dorsal vein of the penis, and the deep groove on the under surface
receives the corpus spongiosum. The root of the penis is connected to the sym-
physis pubis by the suspensory ligament.
Structure. The corpora cavernosa consist of a strong fibrous envelope, enclosing
a fibrous reticular structure, containing erectile tissue in its meshes, and divided
into two separate portions by an incomplete fibrous septum.
The fibrous investment is extremely dense, of considerable thickness, and
highly elastic; it not only invests the surface of the organ, but sends off numerous
fibrous bands itraheculcB) from its inner surface, as well as from the surfaces of
the septum, which cross its interior in all directions, subdividing it into a number
of separate compartments, which present a spongy structure, in which the erectile
tissue is contained.
The trabecular structure fills the interior of the corpora cavernosa. Its com-
ponent fibres are larger and stronger around the circumference than at the centre
of the corpora cavernosa; they are also thicker behind than in front. The inter-
spaces, on the contrary, are larger at the centre than at the circumference, their
long diameter being directed transversely, and they are largest anteriorly. They
are lined by a layer of squamous epithelium.
The fibrous septum forms an imperfect partition between the two corpora
cavernosa; it is thick and complete behind, but in front it is incomplete, and con-
sists of a number of vertical bands of fibrous tissue, which are arranged like the
teeth of a comb, extending between the dorsal and urethral surface of the corpus
cavernosum; hence the name septum pectiniforme. The fibrous investment and
septum consist of longitudinal bands of white fibrous tissue, with numerous elastic
and muscular fibres.
The trabecul^e also consist of white fibrous tissue, elastic fibres, and plain
muscular fibres, and enclose arteries and nerves.
The Corpus Spongiosum encloses the urethra, and is situated in the deep
groove on the under surface of the corpora cavernosa. It commences posteriorly
in front of the deep perinseal fascia, between the diverging crura of the corpora
cavernosa, where it forms a rounded enlargement, the bulb, and terminates ante-
riorly in another expansion, the glans penis, which overlays the anterior rounded
extx'emity of the corpus cavernosum; its central portion or body is cylindrical,
and tapers slightly from behind forwards.
The bulb varies in size in different subjects; it receives a fibrous investment
from the anterior layer of the deep perinasal fascia, and is surrounded by the
Accelerator urinae muscle. The urethra enters the bulb nearer its upper than
its lower surface, being surrounded by a layer of erectile tissue, named by Kobelt,
the colliculi bulbi, a thin prolongation of which is continued backwards around
the membranous and prostatic portions of the canal to the neck of the bladder,
lying immediately beneath the mucous membrane. The portion of the bulb below
XX
674 MALE GENERATIVE OEGANS.
the urethra presents a partial division into two lobes, being marked externally by
a linear raphe, whilst internally there projects inwards, for a short distance, a
thin fibrous septum, most distinct in early life.
Structure. The corpus spongiosum consists of a trabecular structure, enclosed
in a strong fibrous envelope, and containing in its meshes erectile tissue. The
fibrous envelope is thinner, whiter in colour, and more elastic than that of the
corpus cavernosum. The trabeculse are delicate, uniform in size, and the meshes
between them small, their long diameter, for the most part, corresponding with
that of the penis. A thin layer of muscular fibres, continuous behind with those
of the bladder, forms part of the outer coat of the corpus spongiosum.
Erectile tissue consists essentially of an intricate venous plexus, lodged in the
interspaces between the trabeculse. The veins forming this plexus are so nume-
rous, and communicate so freely with one another, as to present a cellular appear-
ance when examined by means of a section; their walls are extremely thin and
lined by squamous epithelium. The veins are smaller in the glans penis, corpus
spongiosum, and circumference of the corpus cavernosum, than in the central part
of the latter, where they are of large size and much dilated. They return the
blood by a series of vessels, some of which emerge in considerable numbers from
the base of the glans penis, and converge on the dorsum of the organ to form the
dorsal vein: others pass out on the upper surface of the corpus spongiosum and
join the dorsal vein: some emerge from the under surface between the corpus
cavernosum and spongiosum, and receiving branches from the latter, wind round
the sides of the penis to terminate in the dorsal vein; but the greater number
pass out at the root of the penis, and join the prostatic plexus and pudendal
veins.
The arteries of the penis are derived from the internal pudic. Those supplying
the corpus cavernosum are the arteries of the corpus cavernosum, and branches from
the dorsal artery of the penis, which perforate the fibrous capsule near the fore
part of the organ. Those to the corpus spongiosum are the arteries of the bulb.
Additional branches are described by Kobelt as arising from the trunk of the
internal pudic; they enter the bulbous enlargement on the corpora cavernosa
and spongiosum. The arteries, on entering the cavernous structure, divide into
branches, which are supported and enclosed by the trabeculse; according to
Miiller, some of these branches terminate in a capillary network, which commu-
nicates with the veins as in other parts, whilst others are more convoluted, and
assume a tendril-like appearance; hence the name helicine arteries, which is given
to these peculiar vessels. The helicine arteries are most abundant in the back
part of the corpus cavernosum and spongiosum; they have not been seen in the
glans penis. The existence of these vessels is denied by Valentin, who describes
the smallest branches of the arteries as terminating by wide funnel-shaped orifices,
which open directly into the venous cavities.
The lymphatics of the penis consist of a superficial and deep set; the former
terminate in the inguinal glands; the latter emerge from the corpora cavernosa
and spongiosum, and passing beneath the pubic arch, join the deep lymphatics of
the pelvis.
The nerves are derived from the internal pudic nerve and the hypogastric
plexus. On the glans and bulb some filaments of the cutaneous nerves have
Pacinian bodies connected with them.
The Testes and their Coverings.
The testes are two small glandular organs, which secrete the semen: they are
situated in the scrotum, being suspended by the spermatic cords. At an early
period of foetal life, the testes are contained in the abdominal cavity, behind the
peritoneum. Before birth, they descend to the inguinal canal, along which they
pass with the spermatic cord, and, emerging at the external abdominal ring, they
descend into the scrotum, becoming invested in their course by numerous
SCROTUM. 675
coverings, derived from the serous, muscular, and fibrous layers of the abdominal
parietes, as well as by the scrotum. The coverings of the testis are, the
Skin ) c; ,
-p. ^ } Scrotum.
JJartos )
Intercolumnar, or External spermatic fascia.
Cremaster muscle.
Infundibuliform, or Fascia propia (Liternal spermatic fascia).
Tunica vaginalis.
The Scrotum is a cutaneous pouch, which contains the testes and part of the
spermatic cords. It is divided into two lateral halves, by a median line, or raphe,
which is continued forwards along the under surface of the penis, and backwards
along the middle line of the perinasum to the anus. Of these two lateral portions,
the left is larger than the right, and corresponds with the greater length of the
spermatic cord on the left side. Its external aspect varies under different
circumstances: thus, under the influence of warmth, and in old and debilitated
persons, it becomes elongated and flaccid; but, under the influence of cold, and
in the young and robust, it is short, corrugated, and closely applied to the
testes.
The scrotum consists of two layers, the integument and the dartos.
The integument is very thin, of a brownish colour, and generally thrown into
folds or rug£e. It is provided with sebaceous follicles, the secretion of which has
a peculiar odour, and beset with thinly scattered, crisp hairs, the roots of which
are seen through the skin.
The dartos is a thin layer of loose reddish tissue, endowed with contractility:
it forms the proper tunic of the scrotum, is continuous, around the base of the
scrotum, with the superficial fascia of the groin, peringeum, and inner side of the
thighs, and sends inwards a distinct septum, septum scroti, which divides it into
two cavities for the two testes, the septum extending between the raphe, and
under surface of the penis, as far as its root.
The dartos is closely united to the skin externally, but connected with the sub-
jacent parts by delicate areolar tissue, upon which it glides with the greatest
facility. The dartos is very vascular, and consists of a loose areolar tissue, con-
taining unstriped muscular fibre. Its contractility is slow, and excited by cold
and mechanical stimuli, but not by electricity.
The Intercolumnar Fascia is a thin membrane, derived from the margin of the
pillars of the external abdominal ring, during the descent of the testis in the
foetus, being prolonged downwards around the surface of the cord and testis. It
is separated from the dartos by loose areolar tissue, which allows of considerable
movement of the latter upon it, but is intimately connected with the succeeding
layer.
The Cremasteric Fascia consists of scattered bundles of muscular fibres
( Cremaster muscle), derived from the lower border of the Internal oblique muscle,
and carried down during the descent of the testes.
The Fascia Propria is a thin membranous layer, which loosely invests the
surface of the cord. It is a continuation downwards of the infundibuliform pro-
cess of the fascia transversalis, and is also derived during the descent of the
testis in the foetus.
The Tunica Vaginalis is described with the proper coverings of the testis.
A more detailed account of these coverings may be found in the description of
the surgical anatomy of inguinal hernia.
The Arteries supplying the coverings of the testes are: the superficial and
deep external pudic, from the femoral; the superficial perinseal branch of the
internal pudic; and the cremasteric branch from the epigastric.
The Veins follow the course of the corresponding arteries.
The Lymphatics terminate in the inguinal glands.
The Nerves &ve, the ilio-inguinal and ilio-hypogastric branches of the lumbar
X X 2
676 MALE GENERATIVE OEGANS.
plexus, the two superficial perinseal branches of the internal pudic nerve, the
inferior pudendal branch of the small sciatic nerve, and the genital branch of the
genito-crural nerve.
The Spermatic Cord extends from the internal abdominal ring, where the
structures of which it is composed converge, to the back part of the testicle. It
is composed of arteries, veins, lymphatics, nerves, and the excretory duct of the
testicle, connected together by areolar tissue, and invested by its proper cover-
ings. In the abdominal wall, it passes obliquely along the inguinal canal, lying
at first beneath the Internal oblique, and upon the fascia transversalis, but, nearer
the pubes, it rests on Poupart's ligament, having the aponeurosis of the External
oblique in front of it, and the conjoined tendon behind it. It then escapes at the
external ring, and descends nearly vertically into the scrotum. The left cord is
rather longer than the right, consequently the left testis hangs somewhat lower
than its fellow.
The Arteries of the Cord are the spermatic, from the aorta; the artery of the
vas deferens, from the superior vesical; and the cremasteric, from the epigastric
artery.
The spermatic artery supplies the testicle. On approaching this gland, some
branches supj^ly the epididymis, others perforate the tunica albuginea behind, and
spread out on its inner surface, or pass through the fibrous septum in its interior,
to be distributed on the membranous septa, between the separate lobes.
The artery of the vas deferens is a long slender vessel, which accompanies the
vas deferens, ramifying upon the coats of this duct, and anastomosing with the
spermatic artery near the testis.
The cremasteric branch from the epigastric supplies the Cremaster muscle,
and other coverings of the cord.
The Spermatic Veins leave the back part of -the testis, and receive branches
from the epididymis: they unite to form a plexus {pampiniform plexus), which
forms the chief mass of the cord. They pass up in front of the vas deferens, and
unite to form a single trunk, which terminates, on the right side, in the inferior
vena cava, on the left side, in the left renal vein.
The Lymphatics are of large size, accompany the blood-vessels, and terminate
in the lumbar glands.
The Nerves are the spermatic plexus from the sympathetic. This plexus is
derived from the renal and aortic plexuses, joined by filaments from the hypogastric
plexus, which accompany the artery of the vas deferens.
Testes.
The testes are two small glandular organs, suspended in the scrotum by the
spermatic cords. Each gland is of an oval form, compressed laterally and behind,
and having an oblique position in the scrotum; its upper extremity being directed
forwards and a little outwards; the lower, backwards and a little inwards: the
anterior convex border looks forwards and downwards, the posterior or straight
border, to which the cord is attached, backwards and upwards.
The anterior and lateral surfaces, as well as both extremities of the organ, are
convex, free, smooth, and invested by the tunica vaginalis. The posterior border,
to which the cord is attached, receives only a partial investment from this mem-
brane. Lying upon the outer edge of this border, is a long, narrow, flattened
body, named, from its relation to the testis, the epididymis (eVt St,Svfio<i, testis).
It consists of a central portion, or body, an upper enlarged extremity, the globus
major, or head; and a lower pointed extremity, the tail, or globus minor. The
globus major is intimately connected with the upper end of the testicle by means
of its efferent ducts; and the globus minor is connected with its lower end by
cellular tissue, and a reflection of the tunica vaginalis. The outer surface and
upper and lower ends of the epididymis are free and covered by serous mem-
brane; the body is also completely invested by it, excepting along its posterior
border, and connected to the back of the testis by a fold of the serous membrane.
SPERMATIC CORD; TESTIS.
677
343.— The Testis in Situ. The Tunica
VaginaHs having been laid open.
Attached to the upper end of the testis, or to the epididymis, is a small peduncu-
lated body, the use of which is unknown.
Size and Weight. The average dimen-
sions of this gland are from one and a
half to two inches in length, one inch in
breadth, and an inch and a quarter in
the antero-posterior diameter; and the
weight varies from six to eight drachms,
the left testicle being a little the larger.
The testis is invested by three tunics,
the tunica vaginalis, tunica albuginea,
and tunica vasculosa.
The Tunica Vaginalis is the serous
covering of the testis. It is a pouch of
serous membrane, derived from the peri-
toneum during the descent of the testis
in the foetus, from the abdomen into the
scrotum. After its descent, that portion of
the pouch which extends from the internal
ring to near the upper part of the gland,
becomes obliterated, the lower portion re-
maining as a shut sac, which invests the
outer surface of the testis, and is reflected
on the internal surface of the scrotum;
hence it may be described as consisting of a visceral and parietal portion.
The visceral portion {tunica vaginalis propria), covers the outer surface of
the testis, as well as the epididymis, connecting the latter to the testis by means
of a distinct fold. From the posterior border of the gland, it is reflected on to
the internal surface of the scrotum.
The parietal portion of the serous membrane {tunica vaginalis rejlexa),
is far more extensive than the visceral portion, extending upwards for some
distance in front, and on the inner side of the cord, and reaching below the testis.
The inner surface of the tunica vaginalis is free, smooth, and covered by a layer
of squamous epithelium. The interval between the visceral and parietal layers
of this membrane, constitutes the cavity of the tunica vaginalis.
The Tunica Albuginea is the fibrous covering of the testis. It is a dense
fibrous membrane, of a blueish-white colour, composed of bundles of white fibrous
tissue, which interlace in every direction. Its outer surface is covered by the tunica
vaginalis, except along its posterior border, and at the points of attachment of
the epididymis; hence the tunica albuginea is usually considered as a fibro-serous
membrane, like the dura mater and pericardium. This membrane surrounds the
glandular structure of the testicle, and, at its posterior and upper border, is
reflected into the interior of the gland, forming an incomplete vertical septum,
called the mediastinum testis {corpus Highmorianuni).
The mediastinum testis extends from the upper, nearly to the lower border of
the gland, and is wider above than below. From the front and sides of this
septum, numerous slender fibrous cords {traheculce) are given off", which pass to
be attached to the inner surface of the tunica albuginea: they serve to maintain
the form of the testis, and join, with similar laminae given oflf from the inner
surface of the tunica albuginea, to form spaces which enclose the separate lobules
of the organ. The mediastinum supports the vessels and ducts of the testis in
their passage to and from the substance of the gland.
The Tunica Vasculosa {pia mater testis), is the vascular layer of the testis,
consisting of a plexus of blood-vessels, held together by a delicate areolar tissue.
It covers the whole of the internal surface of the tunica albuginea, sending
ofi" numerous processes between the lobules, which are supported by the fibrous
prolongations from the mediastinum testis.
678
MALE GENERATIVE ORGANS.
Structure. The glandular structure of the testis consists of numerous lobules
{lohuli testis). Their number, in a single testis, is estimated by Berres at 250, and
by Krause, at 400. They differ in size according to their position, those in the
middle of the gland being larger and longer. Each lobule is conical in shape, the
base being directed towards the circumference of the organ, the apex towards
the mediastinum. Each lobule is contained in one of the intervals between
the fibrous cords and vascular processes, which extend between the mediastinum
testis and the tunica albuginea, and consists of from one to three, or more,
minute convoluted tubes, the tuhuli seminiferi. The tubes may be separately
unravelled, by careful dissection under water, and may be seen to com-
mence either by free csecal ends, or by
344. — Vertical Section of the Tes-
ticle, to sliow the arrangement of
the Ducts
TunicaAti,
anastomotic loops. The total number
of tubes is considered by Monro to be
about 300,- and the length of each about
sixteen feet: by Lauth, their number is
estimated at 840, and their average
length two feet and a quarter. Their
diameter varies from 2'"o'o*^ ^^ T5~o ^^ ^^
inch. The tubuli are pale in colour in
early life, but, in old age, they acquire a
deep yellow tinge, from containing much
fatty matter. They consist of a base-
ment membrane, lined by epithelium,
consisting of nucleated granular cor-
puscles, and are enclosed in a delicate
plexus of capillary vessels. In the apices
of the Jobules, the tubuli become less
convoluted, assume a nearly straight
course, and unite together to form from
twenty to thirty larger ducts, of about
■g-^th of an inch in diameter, and these,
from their straight course, are called
vasa recta.
The Vasa Recta, enter the fibrous tissue
of the mediastinum, and pass upwards and
backwards, forming, in their ascent, a
close network of anastomosing tubes, with
exceedingly thin parietes; this constitutes the rete testis. At the upper end of the
mediastinum, the vessels of the rete testis terminate in from twelve to fifteen or
twenty ducts, the vasa efferentia : they perforate the tunica albuginea, and carry
the seminal fluid from the testis to' the epididymis. Their course is at first straight;
they then become enlarged, and exceedingly convoluted, and form a series of coni-
cal masses, the coni vasculosi, which, together, constitute the globus major of the
epididymis. Each cone consists of a single convoluted duct, from six to eight
inches in length, the diameter of which gradually decreases from the testis to
the epididymis. Opposite the bases of the cones, the efferent vessels open at
narrow intervals into a single duct, which constitutes, by its complex convolu-
tions, the body and globus minor of the epididymis. When the convolutions of
this tube are unravelled, it measures upwards of twenty feet in length, and
increases in breadth and thickness as it approaches the vas deferens. The con-
volutions are held together by fine areolar tissue, and by bands of fibrous tissue.
A long narrow tube, the vasculum aberrans of Haller, is occasionally found con-
nected with the lower part of the canal of the epididymis, or with the commence-
ment of the vas deferens, and extending up into the cord for about two or three
inches, where it terminates by a blind extremity, which is occasionally bifurcated.
Its length varies from an inch and a half to fourteen inches, and sometimes
it becomes dilated towards its extremity: more commonly, it retains the same
VAS DEFERENS; VESICIJLiE SEMINALES.
679
diameter throughout. Its structui-e in similar to that of the vas defereuH.
Occasionally, it is found unconnected with the epididymis.
The Vas Deferens, the excretory duct of the testis, is the continuation ol the
epididymis. Commencing at the lower part of the globus minor, it ascends along
the posterior and inner side of the testis and epididymis, and along the back part
of the spermatic cord, through the spermatic canal, to the internal abdominal
ring. From the ring it descends into the pelvis, crossing the external iliac
vessels, and hooks round the outer side of the epigastric artery; at the side of
the bladder, it curves backwards and downwards to its base, crossing outside the
obliterated hypogastric artery, and to the inner side of the ureter. At the base
of the bladder, it lies between it and the rectum, running along the inner border
of the vesicula seminalis. In this situation, it becomes enlarged and saccu-
lated; and, becoming narrowed, at the base of the prostate, unites with the duct
of the vesicula seminalis to form the ejaculatory duct. This tube presents a hard
and cordy sensation to the fingers, is about two feet in length, of cylindrical form,
and about a line and a quarter in diameter. Its walls are of extreme density and
thickness, measuring one-third of a line; and its canal is extremely small,
measuring about half a line.
In structure, the vas deferens consists of three coats: an external, or cellular
coat; a muscular coat, which is thick, dense, elastic, and consists of two longitu-
dinal, and an intermediate circular layer of muscular fibres.
The internal, or mucous coat, is pale, and arranged in longitudinal plicas: its
epithelial covering is of the columnar variety.
Vesicula Seminales.
The Seminal Vesicles are two lobulated membranous pouches, placed between
the base of the bladder and the rectum, and supposed to serve as reservoirs for
345--
-Base of the Bladder, with the Vasa Deferentia
and Vesicula) Seminales.
ITT r*
Jilglit Ejacula.ta ru
duct
the semen. Each sac is somewhat pyramidal in form, the broad end being directed
backwards, and the narrow end forwards towards the prostate. They measure about
two and a half inches in length, about five lines in breadth, and from two to three
lines in thickness. They vary, however, in size, not only in difierent individuals,
but also in the same individual on the two sides. Their upper surface is in
68o MALE GENERATIVE ORGANS.
contact with the base of the bladder, extending from near the termination of the
ureters to the base of the prostate gland. Their under surface rests upon the
rectum, from which they are separated by the recto- vesical fascia. Their poste-
rior extremities diverge backwards and outwards from each other. Their anterior
extremities are pointed, and converge towards the base of the prostate gland,
where each joins with the corresponding vas deferens to form the ejaculatory
duct. Along the inner margin of each vesicula runs the enlarged and some-
what convoluted vas deferens. The inner border of the vesicula, and the corre-
sponding vas deferens, form the lateral boundary of a triangular space, limited
behind by the recto- vesical peritoneal fold; the portion of the bladder included
in this space rests on the rectum, and corresponds with the trigonum vesicas in
its interior.
Structure. Each vesicula consists of a single tube, coiled upon itself, and giving
off several irregular ca^cal diverticula; the separate coils, as well as the diverticula,
being connected together by fibrous tissue. When uncoiled, this tube is about
the diameter of a quill, and varies in length from four to six inches ; it terminates
posteriorly in a cul-de-sac, but its anterior extremity becomes constricted into a
narrow straight duct, which joins on its inner side with the corresponding vas
deferens, and forms the ejaculatory duct.
The Ejaculatory Ducts, two in number, one on each side, are formed by the
junction of the duct of the vesicula seminalis with the vas deferens. Each duct
is about three-quarters of an inch in length; it commences at the base of the
prostate, and runs forwards and upwards in a canal in its substance, and along
the side of the utriculus, to terminate by a separate slit-like orifice upon or within
the margins of the sinus pocularis. The ducts diminish in size, and converge
towards their termination.
Structure. The vesiculae seminales are composed of three coats: external or
fihro-cellular, derived from the recto- vesical fascia; middle ov fibrous coat, which
is firm, dense, fibrous in structure, somewhat elastic, and contains, according
to E. H. Weber, muscular fibres; and an internal or mucous coat, which is pale, of a
whitish-brown colour, and presents a delicate reticular structure, like that seen in
the gall-bladder, but the meshes are finer. It is lined by squamous epithelium.
The coats of the ejaculatory ducts are extremely thin, the outer fibrous layer being
almost entirely lost after their entrance into the prostate, a thin layer of muscular
fibres and the mucous membrane forming the only constituent parts of these
tubes.
Vessels and Nerves. The arteries supplying the vesiculae seminales are derived
from the inferior vesical and middle hgemorrhoidal. The veins and lymphatics
accompany the ai'teries. The nerves are derived from the hypogastric plexus.
The Semen is a thick whitish fluid, having a peculiar odour. It consists of a
fluid, the liquor seminis, and solid particles, the seminal granules, and spermatozoa.
The liquor seminis is transparent, colourless, and of an albuminous compo-
sition, containing particles of squamous and columnar epithelium, with oil globules
and granular matter floating in it, besides the above-mentioned solid elements.
The seminal granules are round finely-granular corpuscles, measuring ^-qVo^^^
of an inch in diameter.
The spermatozoa, or spermatic filaments, are the essential agents in producing
fecundation. They are minute elongated particles, consisting of a small flattened
ovajL extremity or body, and a long slender caudal filament. A small circular
spot is observed in the centre of the body, and at its point of connection with the
tail there is frequently seen a projecting rim or collar. The movements of these
bodies are remarkable, and consist of a lashing and undulatory motion of the tail.
Descent of the Testes.
The testes, at an early period of foetal life, are placed at the back part of the
abdominal cavity, behind the peritoneum, in front and a little below the kidneys.
The anterior surface and sides are invested by peritoneum; the blood-vessels and
DESCENT OF THE TESTES. 68 1
effei'ent ducts are connected with their posterior surface; and attached to the
lower end is a peculiar structure, the gubernaculum testis, which is said to assist
in their descent.
The Gubernaculum Testis attains its full development between the fifth and
sixth months; it is a conical-shaped cord, attached above to the lower end of
the epididymis, and below to the bottom of the scrotum. It is placed behind
the peritoneum, lying upon the front of the Psoas muscle, and completely filling
the inguinal canal. It consists of a soft transparent areolar tissue within, which
often appears partially hollow, surrounded by a layer of striped muscular fibres,
the Cremaster, which ascend upon this body to be attached to the testis. Ac-
cording to Mr. Curling, the gubernaculum, as well as these muscular fibres,
divides below into three processes: the external and broadest is connected with
Poupart's ligament in the inguinal canal; the middle process descends along the
inguinal canal to the bottom of the scrotum, where it joins the dartos; the in-
ternal one is firmly attached to the os pubis and sheath of the Rectus muscle;
some fibres, moreover, are reflected from the Internal oblique on to the front of
the gubernaculum. Up to the fifth month, the testis is situated in the lumbar
region, covered in front and at the sides by peritoneum, and supported in its
position by a fold of this membrane, the mesorchium: between the fifth and sixth
months the testis descends to the iliac fossa, the gubernaculum at the same time
becoming shortened: during the seventh month, it enters the internal abdominal
ring, a small pouch of peritoneum {processus vaginalis) preceding the testis in
its course through the canal. By the end of the eighth month, the testis has
descended into the scrotum, carrying down with it a lengthened pouch of perito-
neum, which communicates by its upper extremity with the peritoneal cavity.
Just before birth, the upper part of this pouch becomes closed, and this obliteration
extends gradually downwards to within a short distance of the testis. The pro-
cess of peritoneum surrounding the testis, which is now entirely cut off from the
general peritoneal cavity, is called the tunica vaginalis.
Mr. Curling considers that the descent of the testis is effected by means of the
muscular fibres of the gubernaculum; those fibres which proceed from Poupart's
ligament and the Obliquus internus are said to guide the organ into the inguinal
canal; those attached to the pubis draw it below the external abdominal ring; and
those attached to the bottom of the scrotum complete its descent. During the
descent of the organ these muscular fibres become gradually everted, forming a
muscular layer, which becomes placed external to the process of the peritoneum,
surrounding the gland and spermatic cord, and constitutes the Cremaster. In the
female, a small cord, corresponding to the gubernaculum in the male, descends to
the inguinal region, and ultimately forms the round ligament of the uterus. A
pouch of peritoneum accompanies it along the inguinal canal, analogous to the
processus vaginalis in the male; it is called the canal of Nuck.
Female Organs of Generation.
THE external Organs of Generation in the female are the mens Veneris, the
labia majora and minora, the clitoris, the meatus urinarius, and the orifice
of the vagina. The term ' vulva' or ' pudendum,' as generally applied, includes
all these parts.
The 3Ions Veneris is the rounded eminence in front of the pubes, formed by a
collection of fatty tissue beneath the integument. It surmounts the vulva, and is
covered with hair at the time of puberty.
346. — The Vulva, External Female Organs of Generation.
The Labia Majora are two prominent longitudinal cutaneous folds, extending
downwards from the mons Veneris to the anterior boundary of the perinseum, and
enclosing an elliptical fissure, the common urino-sexual opening. Each labium is
formed externally of integument, covered with hair; internally, of mucous mem-
brane, which is continuous with the genito-urinary mucous tract; and between
the two, of a considerable quantity of areolar tissue, fat, and a tissue resembling
VULVA. 683
the dartos of the scrotum, besides vessels, nerves, and glands. The labia are
thicker in front than behind, and joined together at each extremity, forming the
anterior and posterior commissures. The interval left between the posterior com-
missure and the margin of the anus is about an inch in length, and constitutes the
peringeum. Just within the posterior commissure is a small, transverse fold, the
frcenulum pudendi or fourchette, which is commonly ruptured in the first partu-
rition, and the space between it and the commissure is called i\\Q fossa navicularis.
The labia are analogous to the scrotum in the male.
The Labia Minora or NymphcB are two small folds of mucous membrane,
situated within the labia majora, and extending from the clitoris obliquely down-
wards and outwards for about an inch and a half on each side of the orifice of the
vagina, on the sides of which they are lost. They are continuous externally with
the labia majora, internally with the inner surface of the vagina. As they con-
verge towards the clitoris in front, each labium divides into two folds, which
surround the glans clitoridis, the superior folds uniting to form the prseputium
clitoridis, the inferior folds being attached to the glans, and forming the frasnum.
The nymphae are composed of mucous membrane, covered by a thin epithelial
layer. They contain a plexus of vessels in their interior, and are provided with
numerous large mucous crypts which secrete abundance of sebaceous matter.
The Clitoris is an erectile structure, analogous to the corpus cavernosum of the
penis. It is situated beneath the anterior commissure, partially hidden between
the anterior extremities of the labia minora. It is an elongated organ, connected
to the rami of the pubes and ischium on each side by two crura; the body is
short, and concealed beneath the labia; its free extremity, the glans clitoridis, is
a small rounded tubercle, consisting of spongy erectile tissue, and highly sensitive.
The clitoris consists of two corpora cavernosa, composed of erectile tissue enclosed
in a dense layer of fibrous membrane, and united together along their inner sur-
faces by an incomplete fibrous pectiniform septum. The clitoris is provided, like
the penis, with a suspensory ligament, and with two small muscles, the Erectores
clitoridis, which are inserted into the crura of the corpus cavernosum.
Between ttxe clitoris above, and the entrance of the vagina below, is a tri-
angular smooth surface, bounded on each side by the nymphse : this is the
vestibule.
The orifice of the urethra {meatus urinarius'), is situated at the back part of
the vestibule, about an inch below the clitoris, and near the margin of the vagina,
surrounded by a prominent elevation of the mucous membrane. Below the
meatus urinarius, is the orifice of the vagina, an elliptical aperture, more or less
closed in the virgin, by a membranous fold, the hymen.
The Hymen is a thin semilunar fold of mucous membrane, stretched across
the lower part of the orifice of the vagina; its concave margin being turned
upwards towards the pubes. Sometimes this membrane forms a complete
septum across the orifice of the vagina, which constitutes an imperforate hymen.
Occasionally, it forms a circular septum, perforated in the centre by a round
opening; sometimes it is cribriform, or its free margin forms a membranous
fringe, or it may be entirely absent. The hymen cannot, consequently, be con-
sidered as a proof of virginity. Its rupture, or the rudimentary condition of the
membrane above referred to, gives rise to those small rounded elevations which
surround the opening of the vagina, the carunculce myrtiformes.
Glands of Bartlioline. On each side of the commencement of the vagina, are
two round, or oblong bodies, of a reddish-yellow colour, and of the size of an
almond: they are analogous to Cowper's glands in the male, and are called the
glands of Bartlioline. Each gland opens by means of a long single duct, upon
the inner side of the nymphge, external to the hymen. Extending from the
clitoris, along either side of the vagina, and lying a little behind the nymphae, are
two large oblong masses, about an inch in length, consisting of a plexus of veins,
enclosed in a thin layer of fibrous membrane. These bodies are narrow in front,
rounded below, and are connected with the crura of -the clitoris and rami of the
684
FEMALE OEGANS OF GENEEATION.
pubes: tliey are termed by Kobelt, the bulbi vestibuli, and he considers them ana-
logous to the bulb of the corpus spongiosum in the male. Immediately in front
of this body is a smaller venous plexus, continuous with the bulbus vestibuli
behind, and the glans clitoridis in front: it is called by Kobelt, the pars inter-
media, and is considered by him as analogous to that part of the body of the
corpus spongiosum which immediately succeeds the bulb.
347. — Section of Female Pelvis, showing position of Viscera,
Bladder.
The bladder is situated at the anterior part of the pelvis. It is in relation,
in front, VTith. t\\Q os pubis; behind, with the uterus, some convolutions of the
small intestine being interposed; its base lies in contact Avith the neck of the
uterus, and with the anterior wall of the vagina. The bladder is larger in the
female than in the male, and very broad in its transverse diameter.
Ukethea.
The urethra is a narrow membranous canal, about an inch and a half in length,
extending from the neck of the bladder to the meatus urinarius. It is placed
beneath the symphysis pubis, imbedded in the anterior wall of the vagina; and
its direction is obliquely downwards and forwards, its course being slightly
curved, the concavity directed upwards. Its diameter, when undilated, is about
a quarter of an inch. The urethra perforates the triangular ligament, precisely
as in "the male, and is surrounded by the muscular fibres of the Compressor
urethras.
Structure. The urethra consists of three coats: muscular, erectile, and mucous.
The muscular coat is continuous with that of the bladder; it extends the whole
length of the tube, and consists of a thick stratum of circular fibres.
VAGINA. 685
A thin layer of spongy, erectile tissue, intermixed with much elastic tissue,
lies immediately beneath the mucous coat.
The mucous coat is pale, continuous, externally, with the vulva, and internally
with that of the bladder. It is thrown into longitudinal folds, one of which,
placed along the floor of the canal, resembles the veru-montanum in the male
urethra. It is lined by laminated epithelium, which becomes spheroidal at the
bladder. Its external orifice is surrounded by a few mucous follicles.
The urethra, from not being surrounded by dense resisting structures, as in the
male, admits of considerable dilatation, which enables the surgeon to remove with
considerable facility, calculi, or other foreign bodies, from the cavity of the
bladder.
Rectum.
The rectum is more capacious, and less curved in the female, than in the male.
The first portion extends from the left sacro-iliac symphysis to the middle of
the sacrum. It is surrounded by peritoneum; and its connections are similar to
those in the male.
The second portion extends to the tip of the coccyx. It is covered by the
peritoneum in front, for a short distance, at its upper part, and is in relation with
the posterior wall of the vagina.
The third portion curves backwards, from the vagina to the anus, leaving a
space which corresponds on the surface of the body to the perineum. Its
extremity is surrounded by the Sphincter muscles, and its sides are supported by
the Levatores ani.
The Vagina.
The vagina is a membranous canal, extending from the vulva to the uterus.
It is situated in the cavity of the pelvis, behind the bladder, and in front of
the rectum. Its direction is curved forwards and downwards, following at first
the line of the axis of the cavity of the pelvis, and afterwards that of the outlet.
It is cylindrical in shape, flattened from before backwards, and its walls are
ordinarily in contact with each other. Its length is about four inches along its
anterior wall, and between five or six along its posterior wall. It is constricted
at its commencement, and becomes dilated near the uterine extremity; it sur-
rounds the vaginal portion of the cervix uteri, at some distance from the os, and
its attachment extends higher up on the posterior than on the anterior wall.
Relations. Its anterior surface is concave, and in relation with the base of
the bladder, and with the urethra. Its posterior surface is convex, and con-
nected to the anterior wall of the rectum, for the lower three-fourths of its
extent, the upper fourth being separated from that tube by the recto-uterine fold
of peritoneum, which forms a cul-de-sac between the vagina and rectum. Its
sides give attachment superiorly to the broad ligaments, and inferiorly to the
Levatores ani muscles and recto-vesical fascia.
Structure. The vagina consists of an external, or muscular coat, a layer of
erectile tissue, and an internal mucous lining.
The muscular coat consists of longitudinal fibres, which surround the vagina,
and are continuous with the superficial muscular fibres of the uterus. The
strongest fasiculi are those attached to the recto-vesical fascia on each side.
The erectile tissue is enclosed between two layers of fibrous membrane: it is
more abundant at the lower than at the upper part of the vagina.
The mucous membrane is continuous, above, with that lining the uterus,
and below, with the integument covering the labia majora. Its inner sur-
face presents, along the anterior and posterior walls, a longitudinal ridge,
or raphe, called the column of the vagina, and numerous transverse ridges, or
rugge, extend outwards from the raphe on each side. These rug^ are most
distinct near the orifice of the vagina, especially in females before parturition.
They indicate its adaptation for dilatation, and are calculated to facilitate its
686 FEMALE ORGANS OF GENERATION.
enlargement during parturition. The mucous membrane is covered with conical
and filiform papillae, and provided with mucous glands and follicles, which are
especially numerous in its upper part, and around the cervix uteri.
The Utektjs.
The uterus is the organ of gestation, receiving the fecundated ovum in its
cavity, retaining and supporting it during the development of the fcetus, and the
principal agent in its expulsion at the time of parturition.
In the virgin state it is pear-shaped, flattened from before backwards, and
situated in the cavity of the pelvis, between the bladder and rectum; it is
retained in its position by the round and broad ligaments on each side, and pro-
jects into the upper end of the vagina below. Its upper end, or base, is
directed upwards and forwards; its lower end, or apex, downwards and back-
wards, in the line of the axis of the inlet of the pClvis, and forming an angle
with the vagina, the direction of which corresponds to the cavity and outlet of
the pelvis. The uterus measures about three inches in length, two in breadth, at
its upper part, and an inch in thickness. It weighs, at puberty, from seven to
twelve drachms, and, after partui'ition, from one ounce and a half to two ounces.
The uterus is divided into fundus, body, cervix, and os uteri.
The Fundus is the upper broad extremity of the organ: it is convex, covered
by peritoneum, and placed on a line below the level of the brim of the pelvis.
The Body gradually narrows from the fundus to the neck. Its anterior sur-
face is flattened, covered by peritoneum in the upper three-fourths of its extent,
and separated from the bladder by some convolutions of the small intestine: the
lower fourth is connected with the bladder. Its posterior surface is convex,
covered by peritoneum throughout, and separated from the rectum by some con-
volutions of the intestine. Its lateral margins are concave, and give attachment
to the broad ligaments, the ligament of the ovary, the Fallopian tube, and round
ligament.
The Cervix is the lower rounded and narrowed portion of the uterus: around
its circumference is attached the upper end of the vagina, which extends upwards
a greater distance behind than in front.
At the vaginal extremity of the uterus is an aperture, the os uteri, round in
the virgin, and transverse after parturition. It is bounded by two lips, an ante-
rior one, which is thick, a posterior narrow and long.
Ligaments. The ligaments of the uterus are six in number: two anterior, two
posterior, and two lateral. They are formed by peritoneum.
The tioo anterior ligaments {vesico-uterine\ are two semilunar folds, which
pass between the neck of the uterus and the posterior surface of the bladder.
The two posterior ligaments {recto-uterine\ pass between the sides of the
uterus and rectum.
The two lateral, or broad ligaments, pass from the sides of the uterus to the
lateral walls of the pelvis, forming a septum across the pelvis, which divides this
cavity into two portions. In the anterior part are contained the bladder, urethra,
and vagina; in the posterior part, the rectum.
The Cavity of the Uterus is small in comparison with the size of the organ:
that portion corresponding to the body is triangular, flattened from before back-
wards, so that its walls are closely approximated, and having its base directed
upwards towards the fundus. At each superior angle is a funnel-shaped cavity,
which constitutes the remains of the division of the body of the uterus into two
cornua; and at the bottom of each cavity is the minute orifice of the Fallopian
tube. At the inferior angle of the uterine cavity, is a small constricted opening,
the internal orifice {ostium internum^ which leads into the cavity of the cervix.
The cavity in the cervix is somewhat cylindrical, flattened from before back-
wards, broader at the centre than at either extremity, and communicates, below,
with the vagina. The walls of the canal present two longitudinal columns,
which run, one on its anterior, the other on its posterior surface; and from these
UTERUS. 687
proceed a number of smaller oblique columns, giving the appearance of branches
from the stem of a tree, and hence the name, arhor vitce uterinus, applied to it.
These folds usually become very indistinct after the first labour.
Structure. The uterus is composed of three coats, an external serous coat, a
middle, or muscular layer, and an internal mucous coat.
The serous coat is derived from the peritoneum: it invests the fundus and
the vphole of the posterior surface of the body of the uterus, but only the upper
three-fourths of its anterior surface.
The muscular coat forms the chief bulk of the substance of the uterus. In
the unimpregnated state, it is dense, firm, of a greyish colour, and cuts almost
like cartilage. It is thick opposite the middle of the body and fundus, and thin
at the orifices of the Fallopian tubes. It consists of bundles of unstriped muscular
fibres, disposed in layers, intermixed with areolar tissue, blood, and lymphatic
vessels and nerves. In the impregnated state, the muscular tissue becomes more
prominently developed, and is disposed in three layers, external, middle, and
internal.
The external layer is placed beneath the peritoneum, disposed as a thin plane
on the anterior and posterior surfaces. It consists of fibres, which pass trans-
versely across the fundus, and, converging at each superior angle of the uterus,
are continued on the Fallopian tubes, the round ligament, and ligament of the
ovary; some passing at each side into the broad ligament, and others running
backwards from the cervix into the recto-uterine ligaments.
The middle layer of fibres presents no regularity in its arrangement, being-
disposed longitudinally, obliquely, and transversely.
The internal, or deep layer, consists of circular fibres arranged in the form of
two hollow cones, the apices of which surround the orifices of the Fallopian tubes,
their bases intermingling with one another on the middle of the body of the
uterus. At the cervix, these fibres are disposed transversely.
The mucous membrane is thin, smooth, and closely adherent to the subjacent
tissue. It is continuous, through the fimbriated extremity of the Fallopian tubes,
with the peritoneum; and through the os uteri, with the mucous lining of the
vagina.
In the body of the uterus, it is smooth, soft, of a reddish colour, lined by
columnar- ciliated epithelium, and presenting, when viewed with a lens, the orifices
of numerous branched tubular glands, which are visible before impregnation, but
become much enlarged in the pregnant state.
In the cervix, the mucous membrane between the rugse and around the os uteri,
is provided with numerous mucous follicles and glands. The small, transparent,
vesicular elevations, so often found within the os and cervix uteri, are due to
closure of the mouths of these follicles, and their distension with its proper
secretion. They were called the ovula of Naboth. The mucous membrane
covering the lower half of the cervix, presents numerous papillae.
Vessels and Nerves. The Arteries of the uterus are the two uterine, from the
internal iliac; and the two ovarian, from the aorta. They are remarkable for
their tortuous course in the substance of the organ, and for their frequent
anastomoses.
The Veins are of large size, and correspond with the arteries. In the impreg-
nated uterus, these vessels are termed the uterine sinuses, consisting of the lining
membrane of the veins adhering to the walls of canals channelled through the
substance of the uterus. They terminate in the uterine plexuses.
The Lymphatics are of large size in the impregnated uterus, and terminate in
the pelvic and lumbar glands.
The Nerves are derived from the inferior hypogastric and spermatic plexuses,
and from the third and fourth sacral nerves.
For an elaborate account of the nerves of this organ, the student should con-
sult Dr. Lee's "Memoir on the Ganglia and Nerves of the Uterus," 1 849; and
Dr. Snow Beck's paper "On the Nerves of the Uteriis." Phil. Trans. 1846.
688 FEMALE ORGANS OF GENERATION.
The form, size, and situation of the uterus, varies at different periods of life, and under
different circumstances.
In the foetus, the uterus is contained in the abdominal cavity, projecting beyond tlie
brim of the pelvis. The cervix is considerably larger than the body.
At ptiberty, the uterus is pyriform in shape, and weighs from eight to ten drachms. It
has descended into the pelvis, the fundus being just below the level of the brim of this
cavity. The arbor vitse is distinct, and extends to the upper part of the cavity of that
organ.
During, and after menstruation, the organ becomes enlarged, and more vascular, its
surfaces rounder; the os externum is rounded, its labia swollen, and the lining membrane
of the body thickened, softer, and of a darker colour.
During fregnancy, the uterus increases in weight from one pound and a half to three
pounds. It becomes enormously enlarged, and projects into the hypogastric and lower
part of the umbilical regions. This enlargement, which continues up to the sixth month
of gestation, is partially due to increased development of pre-existing and new formed
muscular tissue. The round ligaments are enlarged, and the broad ligaments become
encroached u])on by the uterus making its way between their laminae. The mucous mem-
brane becomes more vascular, its mucous follicles and glands enlarged, the rugae and
folds in the canal of the cervix become obliterated ; the blood and lymphatic vessels, as
well as the nerves, according to the researches of Dr. Lee, become greatly enlarged.
After farturition, the uterus nearly regains its usual size, weighing from two to three
ounces, but its cavity is larger than in the virgin state, the external orifice is more marked
and assumes a transverse direction, its edges present a fissured surface, its vessels are
tortuous, and its muscular layers are more defined.
In old age, the uterus becomes atrophied, and paler and denser in texture; a more
distinct constriction separates the body and cervix. The ostium internum, and occasion-
ally the vaginal orifice, often becomes obliterated, and its labia almost entirely disappear.
Appendages of the Uteeus.
The appendages of the uterus are the Fallopian tubes, the ovaries and their
ligaments, and the round ligaments. These structures, together w^ith their nu-
trient vessels and nerves, and some scattered muscular fibres, are enclosed between
the two folds of peritoneum, which constitute the broad ligaments: they are
placed in the following order: in front is the round ligament; the Fallopian
tube occupies the free margin of the broad ligament: the ovary and its ligament
are behind and below the latter.
The Fallopian Tubes, or oviducts, convey the ova from the ovaries to the
cavity of the uterus. They are two in number, one on each side, and situated in
the free margin of the broad ligament, extending from each superior angle of the
uterus to the sides of the pelvis. Each tube varies from three to five inches in
length; its canal is exceedingly minute, and commences at the superior angle of
the uterus by a minute orifice, the ostium internum, which will hardly admit
a fine bristle; it continues narrow along the inner half of the tube; it then
gradually widens into a trumpet-shaped extremity, which becomes contracted at
its termination. This orifice is called the ostium abdominale, and communicates
with the peritoneal cavity. Its margins are surrounded by a series of fringe-like
processes, termed fimbritB, and one of these processes is connected with the outer
end of the ovary. To this part of the tube the name fimbriated extremity is
applied; it is also called morsus diaboli, from the peculiar manner in which it
embraces the surface of the ovary during sexual excitement.
Structure. The Fallopian tube consists of three coats, serous, muscular, and
mucous.
The external or serous coat is derived from the peritoneum.
The middle or muscular coat consists of an external longitudinal and an in-
ternal or circular layer of muscular fibres continuous with those of the uterus.
The internal or mucous coat is continuous with the mucous lining of the
uterus, and at the free extremity of the tube with the peritoneum. It is thrown
into longitudinal folds in the outer part of the tube, which indicate its adaptation
for dilatation, and is covered by columnar ciliated epithelium. This form of
epithelium is also found on the inner and outer surfaces of the fimbrise.
The Ovaries (^testes muliebres, Galen) are analogous to the testes in the male.
FALLOPIAN TUBE; OVARY.
689
They are two oblong flattened oval bodies, situated one on each side of the uterus
in the posterior part of the broad ligament, behind and below the Fallopian tubes.
Each ovary is connected with the broad ligament by its anterior margin; by its
348. — The Uterus and its Appendages. Anterior View.
BrCstTr /lassed Ih
Oot,
inner extremity to the uterus by a proper ligament, the ligament of the ovary;
and by its outer extremity to the fimbriated extremity of the Fallopian tube by a
short ligamentous cord. Each ovary is of a whitish colour, and presents either a
smooth or puckered uneven surface. It is about an inch and a half in length,
three quarters of an inch in width, and nearly half an inch thick, and weighs
from one to two drachms. Its surfaces and posterior convex border are free, its
anterior straight border being attached to the broad ligament.
Structure. The ovary is completely invested by peritoneum, excepting along
its anterior attached margin; beneath this is the proper fibroTis coat of the organ, the
tunica albuginea, which is extremely dense and firm in structure, and encloses a firm
reddish-white vascular structure, the stroma, formed apparently by delicate prolon-
gations continued inwards from the external coat. In the meshes of this tissue are
numerous vesicles, the ovisacs of the future ova, and termed the Graafian vesicles.
Before impregnation they vary in number, from ten to fifteen or twenty, and are
from the size of a pin's head to a pea; but Dr. Martin Barry has shewn, that a
large number of microscopic ovisacs exist in the parenchyma of the organ,
few of which produce ova. These vesicles have thin transparent walls, and are
filled with a clear, colourless, albuminous fluid, the largest vesicles appearing on
the surface of the ovary as semi-transparent elevations. Each vesicle includes, be-
sides the fluid contents above mentioned, a small round vesicular body, the ovum.
The Graafian vesicles have two coats, an external vascular and an internal coat,
called the ovi capsule, which is lined by a granular epithelial layer, the membrana
granulosa. On rupture of the vesicle, the ovum escapes through the fimbriated
extremity of the Fallopian tube to the cavity of the uterus. After conception, a
yellow mass, the corpus luteum, is found in one or both ovaries. The corpus
luteum consists of a circular brownish yellow mass, of moderately firm consistence,
containing a small cavity in its centre, originally occupied by the ovum, and now
more or less obliterated. The cavity is lined by a puckered membrane, the
remains of the ovisac. In recent corpora lutea, the aperture through which the
ovum escaped from the ovisac remains visible; but at a later period this becomes
closed, a small puckered cicatrix on the surface of the ovary indicating the
existence of the aperture. Similar appearances, but of smaller size and wanting
the central cavity, are sometimes found in the unimpregnated ovaries; these are
false corpora lutjea.
Y Y
690 FEMALE ORGANS OF GENERATION.
In the foetus, the ovaries are situated, like the testes, in the lumbar region,
near the kidneys. They may be distinguished from those bodies at an early
period by their elongated and flattened form, and by their position, which is at
first oblique and then nearly transverse. They gradually descend into the
pelvis.
The Ligament of the Ovary is a rounded cord, which extends from each
superior angle of the uterus to the inner extremity of the ovary; it consists of
fibrous tissue, and a few muscular fibres derived from the uterus.
The Round Ligaments are two rounded cords, between four and five inches in
length, situated between the layers of the broad ligament, in front of and below the
Fallopian tube. Commencing on each side at the superior angle of the uterus,
each ligament passes forwards and outwards through the internal abdominal ring,
along the inguinal canal to the labia majora, in which it becomes lost. Each
ligament consists of areolar tissue, vessels, and nerYes, besides a dense bundle of
fibrous tissue, and muscular fibres prolonged from the uterus, enclosed in a dupli-
cature of peritoneum, which in the foetus is prolonged in the form of a tubular
process for a short distance into the inguinal canal: this process is called the
canal of Nuck. It is generally obliterated in the adult, but sometimes remains
pervious even in advanced life. It is analogous to the peritoneal pouch which
accompanies the descent of the testis.
Vessels and Nerves. The Arteries of the ovaries and Fallopian tubes are the
ovarian from the aorta. They anastomose with the termination of the uterine
arteries, and enter the attached border of the ovary.
The Veins follow the course of the arteries; they form a plexus near the
ovary, the pampiniform plexus.
The Nerves are derived from the spermatic plexus, the Fallopian tube receiv-
ing a branch from one of the uterine nerves.
Mammary Glands.
The mammcB, or breasts, are accessory glands of the generative system, which
secrete the milk. They exist in the male as well as in the female; but in the
former only in a rudimentary state, unless their growth is excited by peculiar
circumstances. They are two large hemispherical eminences, situated towards
the lateral aspect of the pectoral region, corresponding to the interval between
the third and sixth or seventh ribs, and extending from the side of the sternum
to the axilla. Their weight and dimensions differ at different periods of life and
in different individuals. Before puberty they are of small size, but enlarge as
the generative organs become more completely developed. They increase during
pregnancy, and especially after delivery, and become atrophied in old age. The
left mamma is generally a little larger than the right. Their base is nearly
circular, flattened or slightly concave, and having their long diameter directed
upwards and outwards towards the axilla; they are separated from the Pectoral
muscles by a thin layer of superficial fascia. The outer surface of the mamma is
convex, and presents, just below the centre, a small conical prominence, the
nipple {mammilla). The surface of the nipple is dark-coloured, and surrounded
by an areola having a coloured tint. In the virgin the areola is of a delicate
rosy hue; about the second month of impregnation it enlarges, and acquires a
darker tinge, which increases as pregnancy advances, becoming, in some cases,
a dark brown, or even black colour. This colour diminishes as soon as lactation
is over, but is never entirely lost through life. These changes in the colour of
the areola are of extreme importance in forming a conclusion in a case of
suspected pregnancy.
The nipple is a cylindrical or conical eminence, capable of undergoing a sort
of erection from mechanical excitement. It is of a pink or brownish hue, its
surface wrinkled and provided with papillae, and its summit perforated by nume-
rous orifices, the apertures of the lactiferous ducts. Near the base of the nipple
and upon the surface of the areola are numerous sebaceous glands, which become
MAMMA. 691
much enlarged during lactation, and present the appearance of email tubercles
beneath the skin. These glands secrete a peculiar fatty substance, which serves
as a protection to the integument of the nipple in the act of sucking. The nipple
consists of numerous vessels, which form a kind of erectile tissue, intermixed
with plain muscular fibres.
Structure. The mamma consists of gland tissue; of fibrous tissue, connecting
its lobes; and of fatty tissue in the intervals between the lobes. The mammary
gland, freed from cellular tissue and fat, is of a pale reddish colour, firm in
texture, circular in form, flattened from before backwards, thicker in the centre
than at the circumference, and presenting several inequalities on its surface,
especially in front. It consists of numerous lobes, and these are composed of
lobules, connected together by areolar tissue, blood-vessels, and ducts. The
smallest lobules consist of a cluster of rounded vesicles, which open into the
smallest branches of the lactiferous ducts; these ducts uniting, form larger
ducts, which terminate in a single canal, corresponding with one of the chief
subdivisions of the gland. The number of excretory ducts varies from
fifteen to twenty: they are termed the tuhuli lactiferi, galactophori. They
converge towards the areola, beneath which they form dilatations, or ampullae,
which serve as reservoirs for the milk, and, at the base of the nipple, become
contracted, and pursue a straight course to its summit, perforating it by
separate orifices considerably narrower than the ducts themselves. The ducts
are composed of areolar tissue, with longitudinal and transverse elastic fibres,
and longitudinal muscular fibres: their mucous lining is continuous, at the point
of the nipple, with the integument: its epithelial lining is of the tessellated or
scaly variety.
Hhe fibrous tissue of the mamma invests the entire surface of the breasts, and
sends down septa between its lobes, connecting them together.
ThQ fatty tissue surrounds the surface of the gland, and occupies the intervals
between its lobes and lobules. It usually exists in considerable abundance, and
determines the form and size of the gland. There is no fat immediately beneath
the areola and nipple.
Vessels and Nerves. The Arteries supplying the mammae are derived
from the thoracic branches of the axillary, the intercostals, and internal
mammary.
The Veins describe an anastomotic circle round the base of the nipple, called
by Hallei", the circulus venosus. From this, large branches transmit the blood to
the circumference of the gland, and end in the axillary and internal mammary
veins.
The Lymphatics run along the lower border of the Pectoralis major to the
axillary glands.
The Nerves are derived from the anterior and lateral cutaneous nerves of
the thorax.
T Y 2
The Surgical Anatomy of Inguinal Hernia.
Dissection (fig. 145). For the dissection of the parts concerned in inguinal hernia,
a male subject, free from fat, should always be selected. The body should be placed
in the prone position, the abdomen and pelvis raised by means of blocks placed
beneath them, and the lower extremities rotated outwards, so as to make the parts as
tense as possible. If the abdominal walls are flaccid, the cavity of the abdomen should be
inflated by an aperture through the umbilicus. An incision should be made along the
middle line, from the umbilicus to the pubes, and continued along the front of the scro-
tum ; and a second incision, from the anterior superior spine of the ilium to just below
the umbilicus. These incisions should divide the integument ; and the triangular-shaped
flap included between them should be reflected downwards and outwards, when the super-
ficial fascia will be exposed.
The superficial fascia in this region consists of two layers, between which are
found the superficial vessels and nerves, and the inguinal lymphatic glands.
The superficial layer is thick, areolar in texture, containing adipose tissue in
its meshes, the quantity of which varies in different subjects. Below, it passes
over Poupart's ligament, and is continuous with the outer layer of the superficial
fascia of the thigh. This fascia is continued as a tubular prolongation around
the outer surface of the cord and testis. In this situation, it changes its character:
it becomes thin, destitute of adipose tissue, and of a pale reddish colour, and
assists in forming the dartos. From the scrotum, it may be traced backwards to
be continuous with the superficial fascia of the j^erinseum. This layer shovild be
removed, by dividing it across in the same direction as the external incisions, and
reflecting it downwards and outwards, when the following vessels and nerves will
be exposed:
The superficial epigastric, circumflex iliac, and external pudic vessels; the
terminal filaments of the ilio-hyopgastric and ilio-inguinal nerves; and the upper
chain of inguinal lymphatic glands.
The superficial epigastric artery crosses Poupart's ligament, and ascends ob-
liquely towards the umbilicus, lying midway between the spine of the ilium and
the pubes. It supplies the integument, and anastomoses with the deep epigastric.
This vessel is a branch of the common femoral artery, and pierces the fascia lata,
below Poupart's ligament. Its accompanying vein empties itself into the internal
saphena, piercing previously the cribriform fascia.
The superficial external pudic artery passes transversely inwards across the
spermatic cord, and supplies the integument of the hypogastric region, and of the
penis and scrotum. This vessel is usually divided in the first incision made in
the operation for inguinal hernia, and usually requires the application of a ligature
to suppress the haemorrhage.
The circumflex iliac artery passes outwards towards the crest of the ilium.
The veins accompanying the latter vessels are usually much larger than the
arteries: they terminate in the internal saphena vein.
Lymphatic vessels are found, taking the saixie course as the blood-vessels: they
return the lymph from the superficial structures in the lower part of the abdomen,
the scrotum, penis, and external surface of the buttock, and terminate in a small
chain of lymphatic glands, three or four in number, which lie on a level with
Poupart's ligament (p. 432).
Nerves. The terminal branch of the ilio-inguinal nerve emerges at the external
abdominal ring; and the hypogastric branch of the ilio-hypogastric nerve perfo-
rates the aponeurosis of the external oblique, above and to the outer side of the
external ring (pp. 519, 520).
The deep layer of superficial fascia should be divided across in the same
INGUINAL HERNIA; SUPERFICIAL DISSECTION.
693
direction as the external incisions, separated from the aponeurosis of the External
oblique, to which it is connected by delicate areolar tissue, and reflected down-
wards and outwards. It is thin, aponeurotic in structure, and of considerable
strength. It is intimately adherent, in the middle line, to the linea alba, and
below, to the whole length of Poupart's ligament and upper part of the fascia
lata. It forms a thin tubular prolongation around the outer surface of the cord,
which blends with the superficial layer, and is continuous with the dartos of the
scrotum. From the back of the scrotum, the conjoined layers may be traced into
the perinaeum, where they are continuous with the deep layer of the superficial
fascia in this region, which is attached, behind, to the triangular ligament, and on
either side, to the rami of the pubes and ischia. The connections of this fascia
serve to explain the course taken by the urine in extravasation of this fluid from
rupture of the urethra; passing forwards from the perinjEum into the scrotum,
it ascends on to the abdomen, but is prevented extending into the thighs by the
attachment of the fascia to the rami of the pubes and ischia, on each side, and
to the deep layer of Poupart's ligament in front.
349.— Inguinal Hernia. Superficial Dissection.
SxteT76tzt
The aponeurosis of the External oblique muscle is exposed on the removal of
this fascia. It is a thin, strong, membranous aponeurosis, the fibres of which are
directed obliquely downwards and inwards. It is attached to the anterior supe-
rior spinous process of the ilium, the spine of the pubes, the pectineal line, front
of the pubes, and linea alba. That portion of the aponeurosis which extends
from the anterior superior spine of the ilium, to the spine of the pubes, is termed
694 SURGICAL ANATOMY OF INGUINAL HERNIA.
Poupart's ligament, or the crural arch; and that portion which is inserted into
the pectineal line, is termed Gimbernat's ligament.
Just above and to the outer side of the crest of the pubes, a triangular interval
is seen in the aponeurosis of the External oblique, called the external abdominal
ring; it transmits the spermatic cord in the male, and the round ligament in the
female. This aperture is oblique in direction, somewhat triangular in form, and
corresponds with the course of the fibres of the aponeurosis. It usually measures
from base to apex about an inch, and transversely about half an inch. It is
bounded below by the crest of the os pubis; above, by a series of curved fibres,
the inter columnar^ which pass across the upper angle of the ring bo as to increase
its strength; and on either side, by the free borders of the aponeurosis, which are
called the columns or pillars of the ring.
The external pillar, which, at the same time, is inferior from the obliquity of
its direction, is the strongest; it is formed by that portion of Poupart's ligament,
which is inserted into the spine of the pubes; it projects forwards, and forms a
kind of groove or canal, upon which the spermatic cord rests.
The internal or superior pillar is a broad, thin, flat band, which interlaces
with its fellow of the opposite side, in front of the symphysis pubis, that of the
right side being most superficial.
The external abdominal ring gives passage to the spermatic cord in the male,
and round ligament in the female; it is much larger in men than women on
account of the large size of the spermatic cord, and hence the greater frequency
of inguinal hernia in the former sex.
The Intercolumnar fibres are a series of curved tendinous fibres, which arch
across the lower part of the aponeurosis of the External oblique. They have re-
ceived their name from stretching across between the two pillars of the external
ring; they increase the strength of the membrane which bounds the upper part
of this aperture, and prevent the divergence of the pillars from one another. They
are thickest below, where they are connected to the outer third of Poupart's liga-
ment, and taking a curvilinear course, the convexity of which is directed down-
wards, are inserted into the linea alba. They are much thicker and stronger at
the outer angle of the external ring than internally, and are more strongly de-
veloped in the male than in the female. These fibres are continuous with a thin
fascia, which is closely connected to the margins of the external ring, and has
received the name of the intercolumnar or external spermatic fascia; it forms a
tubular prolongation around the outer surface of the cord and testis, and encloses
them in a distinct sheath. The sac of an inguinal hernia, in passing through the
external abdominal ring, receives an investment from the intercolumnar fascia.
The finger should be introduced a slight distance into the external ring, and if
the limb is extended and rotated outwards, the aponeurosis of the External oblique,
together with the iliac portion of the fascia lata, will be felt to become tense, and
the external ring much contracted; if the limb is, on the contrary, flexed upon
the pelvis and rotated inwards, this aponeurosis will become lax, and the external
ring sufficiently enlarged to admit the finger with comparative ease; hence the
latter position should always be assumed in cases where the taxis is applied for
the reduction of an inguinal hernia, in order that the abdominal walls may be as
much relaxed as possible.
The aponeurosis of the External oblique should be removed by dividing it across in the
same direction as the external incisions, and reflecting it outwards ; great care is requisite
in separating it from the aponeurosis of the muscle beneath. The lower part of the In-
ternal oblique and the Cremaster are then exposed, together with the inguinal canal,
which contains the spermatic cord (fig. 350). The mode of insertion of Poupart's liga-
ment and Gimbernat's ligament into the pubes should also be examined.
Pouparfs Ligament, or the crural arch, extends from the anterior superior
spine of the ilium to the spine of the pubes. It is also attached to the pectineal
line to the extent of about an inch, forming Gimbernat's ligament. Its general
direction is curved toM'^ards the thigh, where it is continuous with the fascia lata.
INTERNAL OBLIQUE; CREMASTER.
695
It3 outer half Is rounded, oblique In Its direction, and continuous with the iliac
fascia. Its inner half gradually widens at its attachment to the pubes, is more
horizontal in direction, and lies behind the spermatic cord.
Gimberna£ s Ligament is that portion of the aponeurosis of the External ob-
lique which is inserted into the pectineal line; it is thin, membranous in structure,
triangular in shape, the base directed outwards, and passes upwards and back-
wards beneath the spermatic cord, from the spine of the 03 pubis to the pectineal
line, to the extent of about half an inch.
The Internal oblique Muscle has been described (p. 231). The part which is
now exposed is partly muscular and partly tendinous in structure. Those fibres
which arise from the outer part of Poupart's ligament are thin, pale in colour,
curve downwards, and terminate in an aponeurosis, which passes in front of the
Rectus and Pyramidalis muscles, to be inserted into the crest of the os pubis and
350. — Inguinal Hernia, showing the Internal Oblique,
Cremaster, and Spermatic Canal.
y-X
pectineal line, to the extent of half an inch, in common with that of the Trans-
versalis muscle, forming by their junction the conjoined tendon. This tendon is
placed immediately behind Gimbernat's ligament and the external abdominal ring,
and serves to strengthen what would otherwise be a very weak point in the
abdominal wall. When the pouch of inguinal hernia passes directly through the
external ring, forming what is called direct inguinal hernia, the conjoined tendon
usually forms one of its coverings.
The Triangular Ligament is a band of tendinous fibres, of a triangular shape,
which is continued from Poupart's ligament at its attachment to the pectineal
line upwards and inwards, beneath the inner pillar of the external ring to the
linea alba.
The Cremaster is a slender muscular fasciculus, .which arises from the middle of
Poupart's ligament at the inner side of the Internal oblique, being connected with
696 SUEGICAL ANATOMY OF INGUINAL HERNIA.
this muscle, and also occasionally with the Transversalis. It passes along the
outer side of the spermatic cord, descends with it through the external ring upon
the front and sides of the cord, and forms a series of loops, which diifer in thick-
ness and length in different subjects. Those at the upper part of the cord are exceed-
ingly short, but they become in succession longer and longer, the longest reaching
down as low as the testicle, where a few are inserted into the tunica vaginalis.
These loops are united together by areolar tissue, and form a thin covering over the
cord, the fascia cremasterica. The fibres ascend along the inner side of the cord,
and are inserted, by a small pointed tendon, into the crest of the os pubis and
front of the sheath of the Rectus muscle.
It will be observed, that the origin and insertion of the Cremaster is precisely
similar with that of the lower fibres of the Internal oblique. This fact affords an
easy explanation of the manner in which the testicle and cord are invested by
this muscle. At an early period of foetal life, the "testis is placed at the lower
and back part of the abdominal cavity, but during its descent towards the scrotum,
which takes place before birth, it passes beneath the arched border of the Internal
oblique. In its passage beneath this muscle some fibres are derived from its
lower part, which accompany the testicle and cord into the scrotum.
It occasionally happens that the loops of the Cremaster surround the cord,
some lying behind as well as in front. It is probable, that under these circum-
stances the testis, in its descent, passed through instead of beneath the fibres of
the Internal oblique.
In the descent of an oblique inguinal hernia, which takes the same course as
the spermatic cord, the Cremaster muscle forms one of its coverings. This muscle
becomes largely developed in cases of hydrocele and large old scrotal hernia. No
such muscle exists in the female, but an analogous structure is developed in those
cases where an oblique inguinal hernia descends beneath the margin of the Internal
oblique.
The Internal oblique should be detached from Poupart's ligament, separated from the
Transversalis to the same extent as in the previous incisions, and reflected inwards on
to the sheath of the Rectus (fig. 354). The circumflex ilii vessels, which lie between
these two muscles, form a valuable guide to their separation.
The Transversalis 3Iuscle has been previously described (p. 233.) Its lower
part is partly fleshy and partly tendinous in structure; this portion arises from
the outer third of Poupart's ligament, and arching downwards and inwards over
the cord, terminates in an aponeurosis, which is inserted into the linea alba, the
crest of the pubes, and into the pectineal line to the extent of an inch, forming,
together with the Internal oblique, the conjoined tendon. Between the lower
border of this muscle and Poupart's ligament, a space is left in which is seen
the fascia transversalis.
The Inguinal, or Spermatic Canal, contains the spermatic cord in the male,
and the round ligament in the female. It is an oblique canal, about an inch and a
half in length, directed downwards and inwards, and placed parallel with, and a
little above, Poupart's ligament. It communicates, above, with the cavity of the
abdomen, by means of the internal abdominal ring, which is the point where the
cord enters the spermatic canal; and terminates, below, at the external ring. It
is bounded in front, in its whole length, by ■ the aponeurosis of the External
oblique, and by the Intei'nal oblique for its outer third; behind, by the trans-
versalis fascia, the conjoined tendon of the Internal oblique and Transversalis,
and the triangular ligament; above, by the arched fibres of the Internal oblique
and Transversalis; below, by the union of the fascia transversalis with Poupart's
ligament. That form of protrusion in which the intestine follows the course
of the spermatic cord along the spermatic canal, is called oblique inguinal
hernia.
The Fascia Transversalis is a thin aponeurotic membrane, which lies between
the inner surface of the Transversalis muscle and the peritoneum. It forms part
SPERMATIC CANAL; INTERNAL RING.
697
of the general layer of fascia whicii lines the interior of the abdominal and pelvic
cavities, and is directly continuous with the iliac and pelvic fasciae.
In the inguinal region, the transversalis fascia is thick and dense in struc-
ture, and joined by fibres from the aponeurosis of the Transversalis; but it
becomes thin and cellular as it ascends to the Diaphragm. Below, it has the
following attachments: external to the femoral vessels, it is connected to the
posterior margin of Poupart's ligament, and is there continuous with the iliac
fascia. Internal to these vessels, it is thin, and attached to the pubes and pecti-
neal line, behind the conjoined tendon with which it is united; and, correspond-
ing to the point where the femoral vessels pass into the thigh, this fascia descends
in front of them, forming the anterior wall of the crural sheath.
351. — Inguinal Hernia, showing the Tranaversalis Muscle,
the TransversaUs Fascia, and the Internal Abdominal Ring.
The Internal Abdominal Ring is situated in the transversalis fascia, midway
between the anterior superior spine of the ilium and the spine of the pubes, and
about half an inch above Poupart's ligament. It is of an oval form, the extremi-
ties of the oval directed upwards and downwards, varies in size in different
subjects, and is much larger in the male than the female. It is bounded, above,
by the arched fibres of the Transversalis muscle, and internally, by the epigastric
vessels. It transmits the spermatic cord in the male, and the round ligament in
the female; and from its circumference, a thin, funnel-shaped membrane, the
infundibuliform, or transversalis fascia, is continued round the cord and testis,
enclosing them in a distinct p(|uch. When the sac of an oblique inguinal hernia
passes through the internal ring, the transversalis fascia forms one of its
coverings.
Between the peritoneum and the transversalis fascia, is a quantity of loose
areolar tissue. In some subjects it is of considerable thickness, and loaded with
698 SURGICAL ANATOMY OF INGUINAL HERNIA.
adipose tissue. Opposite the internal ring, it is continued round the surface of
the cord, forming for it a loose sheath.
The Epigastric Artery bears a very important relation to the internal abdo-
minal ring. This vessel lies between the transversalis fascia and peritoneum, and
passes obliquely upwards and inwards, from its origin from the external iliac, to
the margin of the sheath of the Rectus muscle. In this course, it lies along the
lower and inner margin of the internal ring, and beneath the commencement of
the spermatic cord, the vas deferens curving round it as it passes from the ring
into the pelvis.
The Peritoneum, corresponding to the inner surface of the internal ring, pre-
sents a well-marked depression, the depth of which varies in different subjects.
A thin fibrous band is continued from it along the front of the cord, for a variable
distance, and becomes ultimately lost. This is the remains of the pouch of
peritoneum which, in the foetus, accompanies the cord and testis into the scrotum,
the obliteration of which commences soon after birth. In some cases, the fibrous
band can only be traced a short distance; but occasionally, it may be followed, as
a fine cord, as far as the upper end of the tunica vaginalis. Sometimes the tube
of peritoneum is only closed at intervals, and presents a sacculated appearance;
or a single pouch may extend along the whole length of the cord, which may be
closed above ; or the pouch may be directly continuous with the peritoneum by an
opening at its upper part.
Inguinal Hernia.
Inguinal hernia includes that form of protrusion which makes its way through
the abdomen in the inguinal region.
There are two principal varieties of inguinal hernia: external, or oblique, and
internal, or direct.
External, or Oblique Inguinal Hernia, the most frequent of the two, is that
form of protrusion which takes the same course as the spermatic cord. It is
called external, from the neck of the sac being on the outer or iliac side of the
epigastric artery.
Internal, or Direct Inguinal Hernia, is that form of protrusion which does
not follow the same course as the cord, but protrudes through the abdominal wall
on the inner or pubic side of the epigastric artery.
Oblique Inguinal Hernia.
In oblique inguinal hernia, the intestine escapes from the abdominal cavity
at the internal ring, pushing before it a pouch of peritoneum, which forms the
hernial sac. As it enters the inguinal canal, it receives an investment from the
subserous areolar tissue, and is enclosed in the infundibuliform process of the
transversalis fascia. In passing along the inguinal canal, it displaces upwards
the arched fibres of the Transversalis and Internal oblique muscles, and is sur-
rounded by the fibres of the Cremaster. It then passes along the front of the
cord, and escapes from the inguinal canal at the external ring, receiving an
investment from the intercolumnar fascia. Lastly, it descends into the scrotum,
receiving coverings from the superficial fascia and the integument. ■
The various coverings of this form of hernia, after it has passed through the
external ring, are, from without inwards, the integument, superficial fascia, inter-
columnar fascia, Cremaster muscle, transversalis fascia, subserous cellular tissue,
and peritoneum.
This form of hernia lies in front of the vessels of the spermatic cord, and
seldom extends below the testis, on account of the intimate adhesion of the
coverings of the cord to the tunica vaginalis.
The seat of stricture in oblique inguinal hernia, is either at the external ring, in
the inguinal canal, caused by the fibres of the Internal oblique or Transversalis;
or at the internal ring, more frequently in the latter situation. If it is situated at
the external ring, the division of a few fibres at one point of its circumference, is
VARIETIES OF mGUINAL HERNIA. 699
all that is necessary for the replacement of the hernia. If in the inguinal canal,
or at the internal ring, it will be necessary to divide the aponeurosis of the
External oblique so as to lay open the inguinal canal. In dividing the stric-
ture, the direction of the incision should be directly upwards.
When the intestine passes along the spermatic canal, and escapes from the
external ring into the scrotum, it is called common oblique inguinal, or scrotal
hernia. If the intestine does not escape from the external ring, but is retained in
the inguinal canal, it is called incomplete inguinal hernia, or bubonocele. In
each of these cases, the coverings which invest it will depend upon the extent to
which it descends in the inguinal canal.
There are two other varieties of oblique inguinal hernia: the congenital, and
infantile.
Congenital Hernia is liable to occur in those cases where the pouch of perito-
neum which accompanies the cord and testis in its descent in the foetus remains
unclosed, and communicates directly with the peritoneum. The intestine descends
along this pouch into the cavity of the tunica vaginalis, and lies in contact with
the testis. This form of hernia has no proper sac, being contained within the
tunica vaginalis.
In Infantile Hernia, the hernial sac descends along the inguinal canal into the
scrotum, behind the pouch of peritoneum which accompanies the cord and testis
into the same part. The abdominal aperture of this pouch is closed, but the
portion contained in the inguinal canal remains unobliterated. The hernial sac
is consequently invested, more or less completely, by the posterior layer of the
tunica vaginalis, from which it is separated by a little loose areolar tissue: so that
in operating upon this variety of hernia, three layers of peritoneum would
require division; the first and second being the layers of the tunica vaginalis,
the third the anterior layer of the hernial sac.
Direct Inguinal Hernia.
In direct inguinal hernia, the protrusion makes its way through some part of
the abdominal wall internal to the epigastric artery, and passes directly through
the abdominal parietes and external ring. At the lower part of the abdominal
wall is a triangular space (Hesselbach's triangle), bounded, externally, by the
epigastric artery; internally, by the margin of the Rectus muscle; below, by
Poupart's ligament. The conjoined tendon is stretched across the inner two-
thirds of this space, the remaining portion of the space being filled in by the
transversalis fascia.
In some cases, the hernial protrusion escapes from the abdomen on the outer
side of the conjoined tendon, pushing before it the peritoneum, the subserous cel-
lular tissue, and the transversalis fascia. It then enters the inguinal canal, passing
along nearly its whole length, and finally emerges from the external ring, receiv-
ing an investment from the intercolumnar fascia. The coverings of this form of
hernia are precisely similar to those investing the oblique form of protrusion.
In other cases, and this is the more frequent variety, the intestine is either
forced through the fibres of the conjoined tendon, or the tendon is gradually dis-
tended in front of it, so as to form a complete investment for it. The intestine
then enters the lower end of the inguinal canal, escapes at the external ring,
lying on the inner side of the cord, and receives additional coverings from the
superficial fascia and the integument. This form of hernia has the same cover-
ings as the oblique variety, excepting that the conjoined tendon is substituted for
the Cremaster, and the infundibuliform fascia is replaced by a part of the general
fascia transversalis.
The seat of stricture in both varieties of direct hernia is most frequently at
the neck of the sac, or at the external ring. In that form of hernia which
perforates the conjoined tendon, it not unfrequently occurs at the edges of the
fissure through which the gut passes. In dividing the stricture, the incision
should in all cases be directed upwards.
700 SURGICAL ANATOMY OF INGUINAL AND FEMORAL HERNIJE.
If the hernial protrusion passes into the inguinal canal, but does not escape
from the external abdominal ring, it forms what is called incomplete direct hernia.
This form of hernia is usually of small size, and, in corpulent persons, very
difficult of detection.
Direct inguinal hernia is of much less frequent occurrence than the oblique,
their comparative frequency being, according to Cloquet, as one to five. It
occurs far more frequently in men than women, on account of the larger size
of the external ring in the former sex. It differs from the oblique in its
smaller size and globular form, dependant most probably on the resistance offered
to its progress by the transversalis fascia and conjoined tendon. It differs also
in its position, being placed over the pubes, and not in the course of the inguinal
canal. The epigastric artery runs along the outer or iliac side of the neck of
the sac, and the spermatic cord along its external and posterior side, not directly
behind it, as in oblique inguinal hernia.
SURGICAL ANATOMY OF FEMORAL HERNIA.
The dissection of the parts comprised in the anatomy of femoral hernia should be per-
formed, if possible, upon a female subject free from fat. The subject should lie upon its
back ; a block is first placed under the pelvis, the thigh everted, and the knee slightly
bent, and retained in this position. An incision should then be made from the anterior
superior sptuous process of the ilium along Poupart's ligament to the symphysis pubis ; a
second incision should be carried transversely across the thigh about six inches beneath
the preceding; and these are to be connected together by a vertical one carried along the
inner side of the thigh. These several incisions should divide merely the integument ;
this is to be reflected outwards, when the superficial fascia will be exposed.
The Superficial Fascia at the upper part of the thigh consists of two layers,
between which are found the cutaneous vessels and nerves, and numerous lym-
phatic glands.
The superficial layer is a thick and dense cellulo-fibrous membrane, in the
meshes of which is found a considerable amount of adipose tissue, which varies in
quantity in different subjects; this layer may be traced upwards over Poupart's
ligament to be continuous with the superficial fascia of the abdomen ; whilst below,
and on the inner and outer sides of the limb, it is continuous with the superficial
fascia covering the rest of the thigh. This layer should be detached by dividing
it across in the same direction as the external incisions; its removal will be facili-
tated by commencing at the lower and inner angle of the space, detaching it at first
from the front of the internal saphena vein, and dissecting it off from the anterior
surface of this vessel and its branches; it should then be reflected outwards, in the
same manner as the integument. The cutaneous vessels and nerves, and super-
ficial inguinal glands, are then exposed, lying upon the deep layer of supei'ficial
fascia. These are the internal saphenous vein, and the superficial epigastric,
superficial circumflexa ilii, and superficial pudic vessels, as well as numerous
lymphatics ascending with the saphena vein to the inguinal glands.
The Internal Saphena Vein is a vessel of considerable size, which ascends
obliquely upwards along the inner side of the thigh, below Poupart's ligament.
It passes through the saphenous opening in the fascia lata to terminate in the
femoral vein. This vessel is accompanied by numerous lymphatics, which return
the lymph from the dorsum of the foot and inner side of the leg and thigh; they
terminate in the inguinal glands, which surround the saphenous opening. Con-
verging towards the same point are the superficial epigastric vessels, which
run across Poupart's ligament, obliquely upwards and inwards, to the lower
part of the abdomen; the circumflexa ilii vessels pass obliquely outwards along
Poupart's ligament to the crest of the ilium; and the superficial external pudic
vessels, pass inwards to the perineeal and scrotal regions. These vessels supply
the subcutaneous areolar tissue and the integument, and are accompanied by
FEMORAL HERNIA; SUPERFICIAL DISSECTION.
701
numerous lymphatic vessels, which return the lymph from the same parts to
the inguinal glands.
The Superficial Inguinal Glands are arranged in two groups, one of which is
disposed parallel with Poupart's ligament; the other is placed beneath this liga-
ment, surrounding the termination of the saphena vein, and following (occasion-
ally) the course of this vessel a short distance along the thigh. The upper chain
receives the lymphatic vessels from the penis, scrotum, lower part of the abdomen,
perinajum, and buttock; the lower chain receives the lymphatic vessels from the
lower extremity.
The Nerves supplying the integument of this region are derived from the ilio-
352. — Femoral Hernia. Superficial Dissectiou.
inguinal, the genito-crural, and anterior crural. The ilio-inguinal nerve may be
found on the inner side of the internal saphena vein, the terminal branch of the
genito-crural nerve outside the vein, and the middle and external cutaneous
nerves more external.
The deep layer of superficial fascia should be divided in the same direction
as the external incisions, and separated from the fascia lata; this is easily effected,,
from its extreme thinness. It is a thin but dense membrane, placed beneath the
subcutaneous vessels and nerves, and upon the surface of the fascia lata. It is
intimately adherent above to the lower margin of Poupart's ligament, and about
one inch below this ligament covers the saphenous opening in the fascia lata,
is closely united to its circumference, and is connected to the sheath of the
702
SURGICAL ANATOMY OF FEMORAL HERNIA.
femoral vessels corresponding to its under surface. The portion of fascia covering
this aperture is perforated by the internal saphena vein, and by numerous blood
and lymphatic vessels; hence it has been termed, from its sieve-like appearance,
the cribriform fascia. A femoral hernia, in passing through the saphenous open-
ing, receives the cribriform fascia as one of its coverings.
The deep layer of superficial fascia, together with the cribriform fascia, having
been removed, the fascia lata is exposed.
The Fascia Lata, already described (p. 277), is a dense fibrous aponeurosis,
vsrhich forms an uniform investment for the whole of this region of the limb. At
the upper and inner part of the thigh, a large oval-shaped aperture is observed in it;
it transmits the internal saphenous vein and other small vessels, and is called the
saphenous opening. In order the more correctly to consider the mode of forma-
353. — Femoral Hernia, shewing Fascia Lata and Saphenous Opening.
tion of this aperture, the fascia lata in this part of the thigh is described as
consisting of two portions, an iliac portion and a pubic portion.
The iliac portion of the fascia lata is situated on the outer side of the saphenous
opening, covering the outer surface of the Sartorius, the Rectus, and the Psoas
and Iliacus muscles. It is attached externally to the crest of the ilium and its
anterior superior spine, to the whole length of Poupart's ligament as far internally
as the spine of the pubes, and into the pectineal line in conjunction with Gimber-
nat's ligament, where it becomes continuous with the pubic portion. From the
spine of the pubes, it is reflected downwards and outwards, forming an arched
FASCIA LATA; SAPHENOUS OPENING. 703
margin, the outer boundary (^superior cornu) of the saphenous opening. This ia
sometimes called the falciform process of the fascia lata (femoral ligament of
Hey); it overlies and is adherent to the sheath of the femoral vessels beneath;
to its edge is attached the cribriform fascia, and it is continuous below w^ith the
pubic portion of the fascia lata by a vs^ell-defined curved margin.
The pubic portion of the fascia lata is situated at the inner side of the saphe-
nous opening: at the lower margin of this aperture, it is continuous with the iliac
portion: traced upwards, it covers the surface of the Pectineus, Adductor longus,
and G-racilis muscles; and passing behind the sheath of the femoral vessels, to
which it is closely united, is continuous with the sheath of the Psoas and Uiacus
muscles, and is finally lost in the fibrous capsule of the hip-joint. This fascia is
attached above to the pectineal line, and internally to the margin of the pubic
arch. It may be observed from this description, that the iliac portion of the
fascia lata passes in front of the femoral vessels, the pubic portion behind them;
an apparent aperture consequently exists between the two, through which the
internal saphena joins the femoral vein.
The Saphenous Opening is an oval-shaped aperture, measuring about an inch
and a half in length, and half an inch in width. It is situated at the upper and
inner part of the thigh, below Poupart's ligament, on the pubic side of its centre,
and is directed obliquely downwards and outwards.
Its outer margin is of a semilunar form, thin, strong, sharply-defined, and lies
on a plane considerably anterior to the inner margin. If this edge is traced
upwards, it will be seen to form a curved elongated process or cornu (the superior
cornu), OT falciform process of Burns, which ascends in front of the femoral vessels,
and curving inwards, is attached to Poupart's ligament and to the spine of the
pubis and pectineal line, where it is continuous with the pubic portion. If traced
downwards, it is found continuous with another curved margin, the concavity of
which is directed upwards and inwards; this is the inferior cornu of the saphe-
nous opening, and ia blended with the pubic portion of the fascia lata covering
the Pectineus muscle.
The inner boundary of the opening is on a plane posterior to the outer margin,
and behind the level of the femoral vessels; it is much less prominent and defined
than the outer, from being stretched over the subjacent Pectineus muscle. It
is through this aperture that a femoral hernia passes after descending along the
crural canal.
If the finger is introduced into the saphenous opening while the limb is moved
in different directions, the aperture will be found to be greatly constricted on
extending the limb, or rotating it outwards, and to be relaxed on flexing the limb
and inverting it: hence the necessity of placing the limb in the latter position in
employing the taxis for the reduction of a femoral hernia.
The iliac portion of the fascia lata, together with its falciform process, should now be
removed, by detaching it from the lower margin of Poupart's ligament, carefully dissecting
it from the subjacent structures, and turning it aside, when the sheath of the femoral
vessels is exposed descending beneath Poupart's ligament (fig. 354).
The Crural Arch, or Poupart's Ligament, is the lower border of the aponeurosis
of the External oblique muscle, which stretches across between the anterior supe-
rior spine of the ilium, to the spine of the os pubis and pectineal line; the portion
corresponding to the latter insertion, is called Gimbernafs ligament. Its direction
is curved downwards towards the thigh, its outer half being oblique, its inner half
nearly horizontal. Nearly the whole of the space included between the crural
arch and innominate bone is filled in by the parts which descend from the abdo-
men into the thigh. The outer half of the space is occupied by the Uiacus and
Psoas muscles, together with the external cutaneous and anterior crural nerves.
The pubic side of the space is occupied by the femoral vessels included in their
sheath, a small oval-shaped interval existing between the femoral vein and the
inner wall of the sheath, which is occupied merely by a little loose areolar tissue,
704
SURGICAL ANATOMY OF FEMORAL HERNIA.
and occasionally a small lymphatic gland; this is the crural canal, along which a
portion of gut descends in femoral hernia.
Gimhernai s Ligament is that part of the aponeurosis of the External ob-
lique muscle, which is reflected downwards and outwards to be inserted into
the pectineal line of the os pubis. It is about an inch in length, larger in the
male than in the female, almost horizontal in direction in the erect posture, and
of a triangular form, the base directed outwards. Its base, or outer margin, is
concave, thin and sharp, lies in contact with the crural sheath, and is blended with
the pubic portion of the fascia lata. Its apex corresponds to the spine of the
pubes. Its posterior margin is attached to the pectineal line. Its anterior margin
is continuous with Poupart's ligament.
3 54. — Femoral Hernia. Iliac Portion of Fascia Lata removed, and Sheath of
Femoral Vessels and Femoral Canal exposed.
Crural Sheath. If Poupart's ligament is divided, the femoral or crural sheath
may be de.monstrated as a continuation downwards of the fascite that line the
abdomen, the transversalis fascia passing down in front of the femoral vessels, and
the iliac fascia descending behind them; these fascise are directly continuous on
the iliac side of the femoral artery, but a small space exists between the femoral
vein and the point where they are continuous on the pubic side of this vessel,
which constitutes the femoral or crural canal. The femoral sheath is closely
adherent to the contained vessels about an inch below the saphenous opening,
becoming blended with the areolar sheath of the vessels, but opposite Poupart's
CRURAL CANAL; FEMORAL RING. 705
ligament it is much larger than is required to contain tlicm; hence the funnel-
shaped form which it presents. The outer border of the slieath is perforated by
the genito-crural nerve. Its inner border is pierced by the internal saphena vein,
and numerous lymphatic vessels. In front it is covered by the iliac portion of
the fascia lata; and behind it is the pubic portion of the same fascia.
Deep Crural Arch. Passing across the front of the crural sheath, and closely
connected with it, is a thickened band of fibres, called the deej} crural arch. It
is apparently a thickening of the fascia transversalis, joined externally to the
centre of Poupart's ligament, and arching across the front of the crural sheath, to
be inserted by a broad attachment into the pectineal line, behind the conjoined
tendon. In some subjects, this structure is not very prominently marked, and not
unfrequently it is altogether wanting.
If the anterior wall of the sheath is removed, the artery and vein are seen
lying side by side, a thin septum sejaarating the two vessels, and another septum
separates the vein from the inner wall of the sheath, the septa stretching between
the anterior and posterior wall of the sheath, so that each vessel is enclosed in a
separate compartment. The interval left between the vein and the inner wall of
the sheath is not filled up by any structure, excepting a little loose areolar tissue,
a few lymphatic vessels, and occasionally a lymphatic gland; this is the femoral
or crural canal, through which a portion of intestine descends in femoral hernia.
The Crural Canal is the narrow interval between the femoral vein and the
inner wall of the crural sheath. Its length is from a quarter to half an inch, and
it extends from Gimbernat's ligament to the upper part of the saphenous opening.
Its anterior wall is very narrow, and formed by the fascia transversalis, Pou-
part's ligament, and the falciform process of the fascia lata.
Its posterior tvall is formed by the iliac fascia and the pubic portion of the
fascia lata.
Its external wall is formed by the fibrous septum covering the inner side of
the femoral vein.
Its in7ier wall is formed by the junction of the transversalis and iliac fasciaa,
which forms the inner side of the femoral sheath.
This canal has two orifices: a lower one, the saphenous opening, closed by the
cribriform fascia; an upper one, the femoral or crural ring, closed by the septum
crurale.
The Femoral or Crural Ring (fig. 355) is the upper opening of the femoral
canal, and leads into the cavity of the abdomen. It is bounded in front by Pou-
part's ligament and the deep crural arch ; behind, by the pubes, covered by the
Pectineus muscle, and the pubic portion of the fascia lata; internally, by Gimber-
nat's ligament, the conjoined tendon, the transversalis fascia, and the deep crural
arch; externally, by the femoral vein, covered by its sheath. The femoral ring is
of an oval form, its long diameter, directed transversely, measures about half an
inch, and it is larger in the female than in the male; hence one of the reasons of
the greater frequency of femoral hernia in the former sex.
Position of Parts around the Ring. The spermatic cord in the male, and round
ligament in the female, lie immediately above the anterior margin of the femoral
ring, and may be divided in an operation for femoral hernia if the incisions for
the relief of the stricture are not of limited extent. In the female this is of little
importance, but in the male the spermatic artery may be divided.
The femoral vein lies on the outer side of the ring.
The epigastric artery, in its passage inwards from the external iliac to the
umbilicus, passes across the upper and outer angle of the crural ring, and is con-
sequently in great danger of being wounded if the stricture is divided in a direc-
tion upwards and outwards.
The communicating branch between the epigastric and obturator lies in front
of the ring.
The circumference of the ring is thus seen to be bounded by vessels in every
z z
7o6.
SURGICAL ANATOMY OF FEMORAL HERNIA.
part excepting internally and behind. It is in the former position that the stric-
ture is divided in cases of strangulated femoral hernia.
The obturator artery, when it arises by a common trunk with the epigastric,
which occurs once in every three subjects and a half, bears a very important rela-
tion to the crural ring (fig. 356). In some cases, it descends on the inner side of
the external iliac vein to the obturator foramen, and will consequently lie on the
outer side of the crural ring, where there is little danger of its being wounded in
the operation for dividing the stricture in femoral hernia. Occasionally, however,
this vessel curves along the free margin of Gimbernat's ligament in its passage to
the obturator foramen; it would, consequently, skirt along the greater part of the
355- — Hernia. The Eelations of tbe Femoral and Internal Abdominal Rings,
seen from within the Abdomen. Eight Side.
356. — Variations in Origin and Course of Obturator Artery.
circumference of the crural canal, and could hardly fail in being wounded in the
operation.
Septum Crurale. The femoral ring is closed by a layer of condensed areolar
tissue, called, by J. Cloquet, the septum crurale. This serves as a barrier to the
protrusion of a hernia through this part. Its upper surface is slightly concave,
and supports a small lymphatic gland, by which it is separated from the subserous
areolar tissue and peritoneum. Its under surface is turned towards the femoral
canal. The septum crurale is perforated by numerous apertures for the passage of
lymphatic vessels, connecting the deep inguinal glands with those surrounding the
external iliac artery.
DESCENT AND COVERINGS OF FEMORAL HERNIA. 707
The size of the femoral canal, the degree of tension of its orifices, and, conse-
quently, the degree of constriction of a hernia, varies according to the position of
the limb. If the leg and thigh are extended, abducted, or everted, the femoral
canal and its orifices are extremely tense from the traction on these parts by
Poupart's ligament and the fascia lata, as may be ascertained by passing the
finger along it. If, on the contrary, the thigh is flexed upon the pelvis,
and, at the same time, adducted and rotated inwards, the femoral canal and its
orifices become considerably relaxed; for this reason, the limb should always be
placed in the latter position when the application of the taxis is made in attempting
the reduction of a femoral hernia.
The septum crurale is separated from the peritoneum by a quantity of loose
subserous areolar tissue. In some subjects this tissue contains a considerable
amount of adipose substance, which, when protruded forwards in front of the sac
of a femoral hernia, may be mistaken for a portion of omentum.
Descent of the Hernia. From the preceding description, it follows, that the
femoral ring must be a weak point in the abdominal wall; hence it is, that when
violent or long-continued pressure is made upon the abdominal viscera, a portion
of intestine may be forced into it, constituting a femoral hernia; and the larger
size of this aperture in the female serves to explain the frequency of this form of
hernia in women.
When a portion of intestine is forced through the femoral ring, it carries before
it a pouch of peritoneum, which forms what is called the hernial sac; it receives
an investment from the subserous areolar tissue, and from the septum crurale,
and descends vertically along the crural canal in the inner compartment of the
sheath of the femoral vessels as far as the saphenous opening: at this point, it
changes its course, being prevented extending further down the sheath on account
of its greater narrowness and close contact with the vessels, and also from the close
attachment of the superficial fascia and crural sheath to the lower part of the circum-
ference of the saphenous opening; it is, consequently, directed forwards, pushing be-
fore it the cribriform fascia, and curves upwards on to the falciform process of the
fascia lata and lower part of the tendon of the External oblique, being covered by
the superficial fascia and integument. While the hernia is contained in the femoral
canal, it is usually of small size, owing to the resisting nature of the surrounding
parts; but when it has escaped from the saphenous opening into the loose areolar
tissue of the groin, it becomes considerably enlarged. The direction taken by a
femoral hernia in its descent is at first downwards, then forwards and upwards;
this should be borne in mind, as in the application of the taxis for the reduction
of a femoral hernia, pressure should be directed precisely in the reverse order.
Coverings of the Heriiia. The coverings of a femoral hernia from within out-
wards are peritoneum, subserous areolar tissue, the septum crurale, crural sheath,
cribriform fascia, superficial fascia, and integument.
Varieties of Femoral Hernia. If the intestine descends along the femoral canal
only as far as the saphenous opening, and does not escape from this aperture, it is
called incomplete femoral hernia. The small size of the protrusion in this form
of hernia, on account of the firm and resisting nature of the canal in which it is
contained, renders it an exceedingly dangerous variety of this disease, from the
extreme difficulty of detecting the existence of the swelling, especially in corpu-
lent subjects. The coverings of an incomplete femoral hernia would be, from with-
out inwards, integument, superficial fascia, falciform process of fascia lata, fnscia
propria, septum crurale, subserous cellular tissue, and peritoneum. When, how-
ever, the hernial tumour protrudes through the saphenous opening, and directs
itself forwards and upwards, it forms a complete femoral hernia. Occasionally,
the hernial sac descends on the iliac side of the femoral vessels, or in front of
these vessels, or even behind them, the sac in the latter instance lying immediately
upon the Pectineus muscle, separated from the femoral vessels by the pubic
portion of the fascia lata.
Z Z 2
7o8 SURGICAL ANATOMY OF FEMORAL HERNIA.
The Seat of Stricture of a femoral hernia varies: it may be in the peritoneum
at the neck of the hernial sac; in the greater number of cases it would appear to
be at the point of junction of the falciform process of the fascia lata with the
lunated edge of Gimbernat's ligament; or at the margin of the saphenous opening
in the thigh. The stricture should in every case be divided in a direction
upwards and inwards; and the extent necessary in the majority of cases is about
two or three lines. By these means, all vessels or other structures of importance,
in relation with the neck of the hernial sac, will be avoided.
Surgical Anatomy of the Perinaeum and
Ischio-Eectal Region.
Dissection. The student should select a well-developed muscular subject, free from fat ;
and the dissection should be commenced early, in order that the parts may be examined
in as recent a state as possible. A staff having been introduced into the bladder, and
the subject placed in the position shown in fig. 357, the scrotum should be raised upwards,
and retained in that position, and the rectum moderately di-stended with tow.
The space which is now exposed, corresponds to the inferior aperture, or outlet
of the pelvis. Its deep boundaries are, in front, the pubic arch and sub-pubic
ligament; behind, the tip of the coccyx; and on each side, the rami of the
pubes and ischia, the tuberosities of the ischia, and great sacro-sciatic ligaments.
The space included by these boundaries is somewhat lozenge-shaped, and is
limited on the surface of the body by the scrotum in front, by the buttocks
behind, and on each side by the inner side of the thighs. It measures, from
before backwards, about four inches, and about three in the broadest part of its
transverse diameter, between the ischial tuberosities. A line drawn transversely
between the anterior part of the tuberosity of the ischium, on either side, in front
of the anus, subdivides this space into two portions. The anterior portion con-
tains the penis and urethra, and is called the perinceum. The posterior portion
contains the termination of the rectum, and is called the ischio-rectal region.
IsCHiO-RECTAL REGION.
The ischio-rectal region corresponds to the portion of the outlet of the pelvis
situated immediately behind the perinaeum: it contains the termination of the
rectum. A deep fossa, filled with fat, is situated on either side of the intestine,
between it and the tuberosity of the ischium: this is called the ischio-rectal
fossa.
The IscJiio- Rectal Region presents, in the middle line, the aperture of the
anus: around this orifice the integument is thrown into numerous folds, which
are obliterated on distension of the intestine. The integument is of a dark
colour, continuous with the mucous membrane of the rectum, and provided with
numerous follicles, which occasionally inflame and suppurate, and may be mistaken
for fistul^e. The veins around the margin of the anus are occasionally much
dilated, forming a number of hard, pendant masses, of a dark bluish colour,
covered partly by mucous membrane, and partly by the integument. These
tumours constitute the disease called external piles.
Dissection. Make an incision through the integument, along the median line, from the
base of the scrotum to the anterior extremity of the anus; carry it around the margins
of this aperture to its posterior extremity, and continue it backwards about an inch
behind the tip of the coccyx. A transverse incision should now be carried across the base
of the scrotum, joining the anterior extremity of the preceding ; a second, carried in the
same direction, should be made in front of the anus ; and a third, at the posterior extre-
mity of the gut. These incisions should be sufficiently extensive to enable the dissector
to raise the integument from the inner side of the thighs. The flaps of skin corresponding
to the ischio-rectal region (fig. 357 — 2), should now be removed. In dissecting the integument
from this region, great care is required, otherwise the External sphincter will be removed,
as it is intimately adherent to the skin.
The Superficial Fascia is exposed on the removal of the skin: it is very thick,
areolar in texture, and contains much fat in its meshes. In it are found ramify-
7IO
SURGICAL ANATOMY OF THE PERINEUM.
ing two or three cutaneous branches of the email sciatic nerve; these turn round
the inferior border of the Gluteus maximus, and are distributed to the integu-
ment in this region.
357. — Dissection of Perinseum and Ischio-Eectal Region.
The External Sphincter is a thin flat plane of muscular fibres, elliptical in
shape, and intimately adherent to the integument surrounding the margin of the
anus. It measures about three or four inches in length, from its anterior to its
posterior extremity, being about an inch in breadth, opposite the anus. It arises
from the tip of the coccyx, by a narrow tendinous band; and from the superficial
fascia in front of that bone; and is inserted into the tendinous centre of the
perinaeum, joining with the Transversus perinsei, and the other muscles inserted
into this part. Like other sphincter muscles, it consists of two planes of muscular
fibre, which surround the margin of the anus, and join at the commissure before
and behind.
Relations. By its superficial surface, with the integument; by its deep surface
it is in contact with the Internal sphincter; and is separated from the Levator
ani by loose areolar tissue.
The Sphincter ani is a voluntary muscle, supplied by the hasmorrhoidal branch of
the fourth sacral nerve. This muscle is divided in the operation for fistula in
ano; and also in some cases of fissure of the rectum, especially if attended
with much pain or spasm. The object of its division is to keep the parts
at rest and in contact during the healing process.
The Internal Sphincter is a muscular ring, about half an inch in breadth,
which surrounds the lower extremity of the rectum, about an inch from the
margin of the anus. This muscle is about two lines in thickness, and is formed
by an aggregation of the involuntary circular fibres of the intestine. It is paler
in colour, and less coarse in texture, than the External sphincter.
The Ischio-Rectal Fossa is situated between the end of the rectum and the
tuberosity of the ischium, on each side. It is triangular in shape, its base
directed to the surface is formed by the integument of the ischio-rectal region; its
apex, directed upwards, corresponds to the point of division of the obturator
fascia, and the thin membrane given off" from it, which covers the outer surface of
the Levator ani (ischio-rectal fascia). Its dimensions are about an inch in
breadth, at the base, and about two inches in depth, being deeper behind than in
front. It is bounded, internally, by the Sphincter ani. Levator ani, and Coccygeus
muscles; externally, by the tuberosity of the ischium, and the obturator fascia,
which covers the inner surface of the Obturator internus muscle; in front, it is
limited by the line of junction of the superficial and deep perinseal fascise; and
behind, by the margin of the Glutseus maximus, and the great sacro-sciatic
ISCHIO-RECTAL FOSSA; PERINEUM. 711
ligament. This space is filled with a large mass of adipose substance, which
explains the frequency with which abscesses in the neighbourhood of the rectum
burrow to a considerable depth.
If the subject has been injected, on placing the finger on the outer wall of
this fossa, the internal pudic artery, with its accompanying veins and nerve,
will be felt about an inch and a half above the margin of the ischial tuberosity,
but approaching nearer the surface as they pass forwards along the inner margin
of the pubic arch. These structures are enclosed in a sheath formed by the
obturator fascia,, the pudic nerve lying below the artery. Crossing the space
transversely, about its centre, are the inferior haemorrhoidal vessels and nerves,
branches of the pudic; they are distributed to the integument of the anus, and
to the muscles of the lower end of the rectum. These vessels are occasionally
of large size, and may give rise to troublesome haemorrhage, when divided in
the operation of lithotomy, or for fistula in ano. At the back part of this space
may be seen a branch of the fourth sacral nerve; and, at the fore part of the
space, a cutaneous branch of the perinseal nerve.
Perineum.
The perinseal space is of a triangular form: its deep boundaries are limited,
laterally, by the rami of the pubes and ischia, meeting in front at the pubic arch;
behind, by an imaginary transverse line, extending between the tuberosity of the
ischium on either side. The lateral boundaries vary, in the adult, from three
inches to three inches and a half in length; and the base from two to three inches
and a half in breadth; the average diameter being two inches and three-quar-
ters. The variations in the diameter of this space are of extreme interest in
connection with the operation of lithotomy, and the extraction of a stone from
the cavity of the bladder. In those cases where the tuberosities of the ischia are
approximated, it would be necessary to make the incisions in the lateral operation
of lithotomy much less oblique, than if the tuberosities were widely separated,
and the perinseal space consequently wider. The perineum is subdivided by the
median raphe into two equal parts. Of these, the left is the one usually selected
to commence the primary incisions in the operation of lithotomy.
In the middle line the perinaeum is convex, and con-esponds to the bulb of
the urethra. The skin covering it is of a dark colour, thin, freely moveable upon
the subjacent parts, and covered with short crisp hairs, which should be removed
before the dissection of the part is commenced. In front of the anus, a promi-
nent line commences, the raphe, continuous in front with the raphe of the scrotum.
The flaps of integument corresponding to this space having been removed, in
the manner shown in fig. 357 — i, the superficial fascia is exposed.
The Superficial Fascia consists of two layers, as in other regions of the body,
superficial and deep.
The superficial layer is thick, loose, and areolar in texture, and contains much
adipose tissue in its meshes, the amount of which varies in different subjects.
In front, it is continuous with the dartos of the scrotum; behind, it is continuous
with the subcutaneous areolar tissue surrounding the anus; and, on either side,
with the same fascia on the inner side of the thighs. This layer should be
carefully removed, after it has been examined, when the deep layer will be
exposed.
The deep layer of superficial fascia (superficial perinaeal fascia) is thin,
aponeurotic in structure, and of considerable strength, serving to bind down the
muscles of the root of the penis. It is continuous, in front, with the dartos of
the scrotum; on either side, it is firmly attached to the margins of the rami of
the pubes and ischia, external to the crus penis, and as far back as the tuberosity
of the ischium; posteriorly, it curves down behind the Transversus perin^i
muscle, to join the lower margin of the deep perinseal fascia. This fascia not
only covers the muscles in this region, but sends down a vertical septum from its
713
SURGICAL ANATOMY OF THE PERINEUM.
under surface which separates the back part of the subjacent space into two,
being incomplete in front.
In rupture of the anterior portion of the urethra, accompanied by extravasation
358.— The Perineeum. The Integument and Superficial Layer of
Superficial Fascia reflected.
of urine, the fluid makes it way forwards, beneath this fascia, into the areolar
tissue of the scrotum, penis, and anterior and lateral portions of the abdomen: it
rarely extends into the areolar tissue on the inner side of the thighs, or backwards
around the anus. This limitation of the extravasated fluid to the parts above-
named, is easy of explanation, when the attachments of the deep layer of the
superficial fascia are considered. When this fascia is removed, the muscles con-
nected with the penis and urethra will be exposed: these are, in the middle line,
the Accelerator urince; on each side, the Erector penis; and behind, the Trans-
versus perinaei.
The Accelerator urince is placed in the middle line of the perinseum, imme-
diately in front of the anus. It consists of two symmetrical halves, united along
the median line by a tendinous raphe. It arises from the central tendon of the
perinasum, and from the median raphe in front. From this point, its fibres diverge
like the plumes of a pen; the most posterior form a thin layer, which are lost on
the anterior surface of the triangular ligament; the middle fibres encircle the
bulb and adjacent part of the corpus spongiosum, and join with the muscle of the
opposite side, on the upper part of this body, in a strong aponeurosis; the anterior
fibres, the longest and most distinct, spread out over the sides of the corpus
cavernosum, to be inserted partly into this body, anterior to the Erector penis;
partly terminating in a tendinous expansion, which covers the dorsal vessels of
t;he penis. The latter fibres are best seen by dividing ' the muscle longitudinally,
and dissecting it outwards from the surface of the urethra.
Actipji. This muscle may serve to accelerate the flow of the urine or semen
MUSCLES OF THE PERESriEUM.
713
along the canal of the urethra. The middle fibres are supposed, by Krause, to
assist in the erection of the corpus spongiosum, by compressing the erectile tissue
359. — The Superficial Muscles and Vessels of the PerinBcum
Grt Sacj'O •Sciatic Zigt-
SujjeH'icial Perineal Artery
Supeificial Perineal Nerve
InterKcsJ- PuAie Ne-rve
Internal Pu^ic Artery
of the bulb. The anterior fibres, according to Tyrrel, also contribute to the
erection of the penis, as they are inserted into, and continuous with, the fascia
penis, compressing the dorsal vein during the contraction of the muscle.
The Erector Penis covers the unattached part of the crus penis. It is an
elongated muscle, broader in the middle than at either extremity, and situated on
either side of the lateral boundary of the perinseum. It arises by tendinous and
fleshy fibres from the inner surface of the tuberosity of the ischium, behind the
crus penis, from the surface of the crus, and from the adjacent portions of the
ramus of the pubes. From these points, fleshy fibres succeed, vs^hich end in an
aponeurosis which is inserted into the sides and under surface of the crus penis.
This muscle compresses the crus penis, and thus serves to maintain this organ
erect.
The Erector Clitoridis resembles the Erector penis in the male, but is smaller
than that muscle.
The Transversus Perincei is a narrow muscular slip, which passes more or less
transversely across the back part of the perinajal space. It arises by a small
tendon from the inner side of the ascending ramus of the ischium, and, passing
obliquely forwards and inwards, is inserted into the central tendinous point of the
perinfBum, joining in this situation with the muscle of the opposite side, the
Sphincter ani behind, and the Accelerator urinal in front.
Between the muscles just examined, a triangular space exists, bounded inter-
nally by the Accelerator urin^, externally by the Erector penis, the base corre-
sponding to the Transversus perintei. The floor of this space is formed by the
triangular ligament of the urethra (deep perinfeal fascia), and, running from
behind forwards in it, are the superficial perina3al vessels and nerves, the trans-
714 SURGICAL ANATOMY OF THE PERINiEUM.
versus perinsei artery coursing along the posterior boundary of the space, resting
upon the Transversus periniei muscle.
In the lateral operation of lithotomy, the knife is carried obliquely across the
back part of this space, downwards and outwards, into the ischio-rectal fossa,
dividing the Transversus peringei muscle and artery, the posterior fibres of the
Accelerator urinas, the superficial periuEeal vessels and nerve, and, more poste-
riorly, the external hasmorrhoidal vessels.
The superficial and transverse perinaeal arteries are described at p. 378; and
the superficial perinseal and inferior pudendal nerves, at pp. 526-28.
The Accelerator Urinse and Erector penis muscles, should now be removed, when the
deep perinseal fascia will be exposed, stretching across the front part of the outlet of the
pelvis. The urethra is seen perforating its centre, just behind the bulb ; and on either
side is the crus penis, connecting the corpus spongiosum with the ramus of the ischium
and pubes.
360. — Deep Perinseal Fascia. On the left side, the anterior layer
has been removed.
Anterior layer oj^
hep. Pirineeti Fascia renmcvcA
COMPRESSOR UHETHR«
Jniernal PuJic ArtV,
Corvpsr's Glajid
The muscles of the perinasum in the female are, the
Sphincter vaginae. Compressor urethrce.
Erector clitoridis. Sphincter ani.
Transversus perinsei. . Levator ani.
Coccygeus.
The Sphincter VagincB surrounds the orifice of the vagina, and is analogous to
the Accelerator uringe in the male. It is attached, posteriorly, to the centraL
tendon of the perinasum, where it blends with the Sphincter ani. Its fibres pass
forwards on each side of the vagina, to be inserted into the corpora cavernosa and
body of the clitoris.
The Erector Clitoridis resembles the Erector penis in the male, but is smaller
than it.
The Transversus Perinoei is inserted into the side of the Sphincter vaginae, and
DEEP PERINiEAL FASCIA. 715
the Levator ani into the side of the vaginse. The other muscles are precisely
similar to those in the male.
The Deej) Perinceal Fascia (triangular ligament), is a dense membranous
lamina, which closes the front part of the outlet of the pelvis. It is triangular
in shape, about an inch and a half in depth, attached above, by its apex, to
the under surface of the symphysis pubis and sub-pubic ligament; and, on each
side, to the rami of the ischia and pubes, beneath the crura penis. Its inferior
margin, or base, is directed towards the rectum, and connected to the central
tendinous point of the perinseum. It is continuous with the deep layer of the
superficial fascia, in front of tlie Transversus perintBi muscle, and with a thin
fascia, which covers the outer surface of the Levator ani muscle.
The deep perinteal fascia is perforated by the urethra, about an inch below the
symphysis pubis. The aperture is circular in form, and about three or four lines
in diameter. Above this is the aperture for the dorsal vein of the penis; and,
outside the latter, the pudic nerve and artery pierce it.
The deep perinaeal fascia consists of two layers, anterior and posterior: these
are separated above, but united below.
The anterior layer is continued forwards, around the anterior part of the mem-
branous portion of the urethra, becoming lost upon the bulb.
The posterior layer is derived from the pelvic fascia: it is continued backwards
around the posterior part of the membranous portion of the urethra, and the
outer surface of the prostate gland.
If the anterior layer of this fascia is detached on either side, the following
parts are seen between it and the posterior layer: the sub-pubic ligament above,
close to the pubes; the dorsal vein of the penis; the membranous portion of the
urethra, and the muscles of the urethra; Cowper's glands, and their ducts; the
pudic vessels and nerve; the artery and nerve of the bulb, and a plexus of
veins.
The Compressor Urethrce (constrictor urethras), surrounds the whole length of
the membranous portion of the ^arethra, and is contained between the two layers
of the deep perinasal fascia. It arises, by aponeurotic fibres, from the upper part
of the ramus of the pubes on each side, to the extent of half or three quarters of
an inch; each segment of the muscle passes inwards, and divides into two
fasciculi, which surround the urethra from the prostate gland behind, to the
bulbous portion of the urethra in front; and unite, at the upper and lower sur-
faces of this tube, with the muscle of the opposite side, by means of a tendinous
raphe.
Circular Muscular Fibres surround the membranous portion of the urethra,
from the bulb in front to the prostate gland behind ; they are placed immediately
beneath the transverse fibres already described, and are continuous with the cir-
cular fibres of the bladder. These fibres are involuntary.
Cowper's Glands are situated immediately below the membranous portion of
the urethra, close behind the bulb, and below the artery of the bulb (p. 672).
The Pudic Vessels and Nerves are placed along the margin of the pubic arch
(P- 379)-
The Artery of the Bulb passes transversely inwards, from the internal pudic
along the base of the triangular ligament, between the two layers of fascia,
accompanied by a branch of the pudic nerve (p. 380).
If the posterior layer of the deep perinteal fascia is removed, and the crus penis
of one side detached from the bone, the under or perinseal surface of the Levator
ani is brought fully into view. This mitscle, with the triangular ligament in front
and the Coccygeus and Pyriformis behind, closes in the outlet of the pelvis.
The Levator ani is a broad thin muscle, situated on each side of the pelvis.
It is attached to the inner surface of the sides of the true pelvis, and descending,
unites with its fellow of the opposite side to form the floor of the pelvic cavity.
It supports the viscera in this cavity, and surrounds the various structures which
pass through it. It arises, in front, from the posterior surface of the body and
7i6 SURGICAL ANATOMY OF THE PERINiEUM.
ramus of the pubes, on the outer side of the symphysis; posteriorly, from the
inner surface of the spine of the ischium: and between these two points, from
the angle of division between the obturator and recto- vesical layers of the pelvic
fascia at their under part: the fibres pass downwards to the middle line of the
floor of the pelvis, and are inserted, the most posterior fibres into the sides of the
apex of the coccyx; those placed more anteriorly unite with the muscle of
the opposite side, in a median fibrous raphe, which extends between the coccyx
and the margin of the anus. The middle fibres, which form the larger portion of
the muscle, are inserted into the side of the rectum, blending with the fibres of
the Sphincter muscles: lastly, the anterior fibres, the longest, descend upon the
side of the prostate gland to unite beneath it with the muscle of the opposite
side, blending with the fibres of the External sphincter and Transversus perinsei
muscles, at the tendinous centre of the perinajum.
The anterior portion is occasionally separated from the rest of this muscle by
cellular tissue. From this circumstance, as well as from its peculiar relation
with the prostate gland, descending by its side and surrounding it as in a sling, it
has been described by Santorini and others as a distinct muscle, under the name
of the Levator prostatce. In the female, the anterior fibres of the Levator ani
descend upon the sides of the vagina.
Relations. By its tipper or pelvic surface with the recto-vesical fascia, which
separates it from the viscera of the pelvis and from the peritoneum. By its outer
or perincBttl surface, it forms the inner boundary of the ischio-rectal fossa; is
covered by a quantity of fat, and by a thin layer of fascia continued from the deep
perinasal fascia. Its posterior border is continuous with the Coccygeus muscle.
Its anterior border is separated from the muscle of the opposite side by a trian-
gular space, through which the urethra, and, in the female, the vagina passes
from the pelvis.
Actions. This muscle supports the lower end of the rectum and vagina, and also
the bladder during the efforts of expulsion.
The Coccygeus is situated behind and parallel with the preceding. It is a
triangular plane of muscular and tendinous fibres, arising, by its apex, from the
spine of the ischium and lesser sacro-sciatic ligament, and is inserted, by its base,
into the margin of the coccyx and into the side of the lower piece of the sacrum.
This muscle is continuous with the posterior border of the Levator ani, and
closes in the back part of the outlet of the pelvis.
Relations. By its inner or pelvic surface, with the rectum. By its external
surface, with the lesser sacro-sciatic ligament. By its posterior border, with the
Pyriformis.
Action. The Coccygasi muscles raise and support the coccyx after it has been
pressed backwards during defecation or parturition.
Position of the Viscera at the Outlet oj the Pelvis. Divide the central tendinous point of
the perinseum, and separate the rectum from its connexions by dividing the fibres of the
Levator ani, which descend upon the sides of the prostate gland and rectum ; turn it
backwards towards the scrotum and coccyx, when the under surface of the prostate gland,
the neck and base of the bladder, the vesiculse seminales, and vasa deferentia will be
exposed.
The Prostate Gland is placed immediately in front of the neck of the bladder,
around the prostatic portion of the urethra, its base being turned backwards, and
its under surface towards the rectum. It is retained in its position by the Levator
prostatas and by the pubo-prostatic ligaments, and is invested by a dense fibrous
covering, continuous with the posterior layer of the deep perinseal fascia. The
longest diameters of this gland are in the antero-posterior direction, and trans-
versely at its base; and hence the greatest extent of incision that can be made in
it without dividing its substance completely across, is obliquely outwards and
backwards. This is the direction in which the incision is made through it in
the operation of lithotomy, the extent of which should seldom exceed an inch in
length. The relations of the prostate to the rectum should be noticed: by means
POSITION OF VISCERA AT THE OUTLET OF THE PELVIS. 717
of the finger introduced into this gut, the surgeon readily detects enlargement or
other disease of this organ; he is enabled also, by the same means, to direct the
point of a catheter when its introduction is attended with mucli difficulty, either
from injury or disease of the membranous or prostatic portions of the urethra.
Behind the prostate is the posterior surface of the neck and base of the bladder;
a small triangular portion of this organ is seen, bounded in front by the prostate
gland, behind by the recto-vesical fold of the peritoneum, on either side by the vesi-
culas seminales and vasa deferentia, and separated from direct contact with the
rectum by the recto-vesical fascia. The relation of this portion of the bladder to
the rectum is of extreme interest to the surgeon. In cases of retention of urine,
this portion of the organ is found projecting into the rectum, between three and
four inches from the margin of the anus, and may be easily perforated during life
without injury to any important parts: this portion of the bladder is frequently
361. — A View of the Position of the Viscera at the Outlet of the Pelvis,
Afteru of Corpus Cavernosum .
HorsaT Artery of P^nis — Z",
Artery of JBuTb.
JhterTutl Pudie Artery-
Cowper^s CRiunJ-
selected for the performance of the operation of tapping the bladder. If the
finger is introduced into the bowel, the surgeon may learn the position, as well as
the size and weight, of a calculus in the bladder; and in the operation for its
removal, if, as is not unfrequently the case, it should be lodged behind an enlarged
prostate, it may be easily displaced from its position by pressing upwards the base
of the bladder from the rectum.
Parts concerned in the Operation of Lithotomy. The triangular ligament must
be replaced, the rectum drawn forwards so as to occupy ils normal position, and
the student should then consider the position of the various parts in reference to
the lateral operation of lithotomy. This operation is usually performed on the left
side of the perinajum, as it is most convenient for the right hand of the operator.
A stafi" having been introduced into the bladder, the first incision is commenced
about an inch and a half in front of the anus, ar little on the left side of the raphe,
and carried obliquely backwards and outwards to- midway between the anus and
tuberosity of the ischium. This incision divides the integument and superficial
yiS
SURGICAL ANATOMY OF THE PERINEUM.
fascia, the external hasmorrhoidal vessels and nerves, and the superficial and
transverse perinasal vessels: if the fore-finger of the left hand is thrust
upwards and forwards into the wound, pressing at the same time the rectum
inwards and backwards, the stafi" may be felt in the membranous portion of the
urethra. The finger is fixed upon the staff", and the structures covering it are
divided with the point of the knife, which must be directed along the groove
towards the bladder, the edge of the knife being carried outwards and back-
wards, dividing in its course the membranous portion of the urethra aud part of ,J,
the left lobe of the prostate gland, to the extent of about an inch. The knife is
then withdrawn, and the fore-finger of the left hand passed along the staff" into
the bladder; the staff" having been withdrawn, and the position of the stone
determined upon, the forceps are introduced over the finger into the bladder. If
the stone is very large, the opposite side of the prostate should be notched before
the forceps is introduced; the finger is now withdrawn, the blades of the forceps
opened, and made to grasp the stone, which must be extracted by slow and
cautious undulating movements.
Parts divided in the operation. The various structures divided in this opera-
tion are as follows; the integument, superficial fascia, external haemorrhoidal
vessels and nerve, the posterior fibres of the Accelerator urinas, the Transversus
perinaei muscle and artery, (and probably the superficial perinaeal vessels and
nerves), the deep perinaeal fascia, the anterior fibres of the Levator ani, part of
the Compressor urethrse, the membranous and prostatic portions of the urethra,
and part of the prostate gland.
362. — A Transverse Section of the Pelvis ; shewing the Pelvic Fascia.
i^YtfpTiorC'Pural ^
X;zi,xrna,l- J'tidCc Vessel s 85 Nerve.
"% of Xsc'^'''
Parts to be avoided in the operation. In making the necessary incisions in the
perinagum for the extraction of a calculus, the following parts should be avoided.
The primary incisions should not be made too near the middle line, for fear of
wounding the bulb of the corpus spongiosum or rectum; nor too far externally,
otherwise the pudic artery may be implicated as it ascends along the inner border
of the pubic arch. If the incisions are carried too far forward, the artery of the
bulb may be divided; if carried too far backwards, the entire breadth of the
PELVIC FASCIA.
719
prostate and neck of the bladder may be cut through, which allows of infiltration
of urine behind the pelvic fascia into the loose cellular tissue between the bladder
and rectum, instead of escaping externally; diffuse inflammation is consequently
set up, and peritonitis from the close proximity of the recto-vesical peritoneal fold
is the consequence. If, on the contrary, the prostate is divided in front of the
base of the gland, the urine makes its way externally, and there is no danger of
any infiltration taking place.
During the operation, it is of great importance that the finger should be passed
into the'bladder before the staff is removed: if this is neglected, and the incision
made through the prostate and neck of the bladder be too small, great difficulty
may be experienced in introducing it afterwards; and in the child, where the
connections of the bladder to the surrounding parts are very loose, the force made
in the attempt is sufficient to displace the bladder up into the abdomen, out of the
reach of the operator. Such a proceeding has not unfrequently occurred, produc-
ing the most embarrassing results, and total failure of the operation.
363. — Side View of the Pelvic Viscera of the Male Subject, showing the Pelvic
and Perinseal Fascise.
It is necessary to bear in mind that the arteries in the perineeum occasionally
take an abnormal course. Thus the artery of the bulb, when it arises, as some-
times happens, from the pudic, opposite the tuber ischii, is liable to be wounded in
the operation for lithotomy, in its passage forwards to the bulb. The accessory
pudic may be divided near the posterior border of the gland, if this is completely
cut across: and the prostatic veins, especially in people advanced in life, are of
large size, and give rise when divided to troublesome hgemorrhage.
Pelvic Fascia.
The pelvic fascia is a thin membrane which lines the whole of the cavity
of the pelvis, and is continuous with the transversalis and iliac fasciae. It is
attached to the brim of the pelvis for a short distance at the side of this cavity,
720 PELVIC FASCIA.
and to the inner surface of the bone around the attachment of the Obturator
internus. At the posterior border of tliis muscle, it is continued backwards
as a very thin membrane in front of the Pyriformis muscle and sacral nerves,
behind the branches of the internal iliac artery and vein which perforate it, to the
front of the sacrum. In front, it follows the attachment of the Obturator internus
to the bone, arches beneath the obturator vessels, completing the orifice of the
obturator canal, and at the front of the pelvis is attached to the loAver part of the
symphysis pubis; being continuous below the pubes with the fascia of the opj)0-
site side so as to close the front part of the outlet of the pelvis, blending with the
posterior layer of the triangular ligament. At the level of a line extending from
the lower part of the symphysis pubis to the spine of the ischium, is a thickened
whitish band; this marks the attachment of the Levator ani muscle to the pelvic
fascia, and corresponds to its point of division into two layers, the obturator and
recto-vesical.
The Obturator fascia descends and covers the Obturator internus muscle.
It is a direct continuation of the pelvic fascia below the white line above men-
tioned, and is attached to the pubic arch and to the margin of the great sacro-
sciatic ligament. This fascia forms a canal for the pudic vessels and nerve in
their passage forwards to the perinfeum, and is continuous with a thin membrane
which covers the perinseal aspect of the Levator ani muscle, called the ischio-rectal
or anal fascia.
The Recto-vesical fascia (visceral layer of the pelvic fascia) descends into
the pelvis upon the upper surface of the Levator ani muscle, and invests the
prostate, bladder, and rectum. From the inner surface of the symphysis pubis a
short rounded band is continued to the upper surface of the prostate and neck of
the bladder, forming the pubo-prostatic or anterior true ligaments of the bladder.
At the side, this fascia is connected to the side of the prostate, enclosing this
gland and the vesical prostatic plexus, and is continued upwards on the surface of
the bladder, forming the lateral true ligaments of the organ. Another prolonga-
tion invests the v-esiculse seminales, and passes across between the bladder and
rectum, being continuous with the same fascia of the opposite side. Another thin
prolongation is reflected around the surface of the lower end of the rectum. The
Levator ani muscle arises from the point of division of the pelvic fascia; the
visceral layer descending upon and being intimately adherent to the upper surface
of this muscle, while the under surface is covered by a thin layer derived from
the obturator fascia, called the ischio-rectal or anal fascia. In the female, the
vagina perforates the recto-vesical fascia and receives a prolongation from it.
INDEX.
Abdomen, 597 ; apertures found in, 597 ;
boundaries of, 697 ; lymphatics of, 435 ;
muscles of, 299 ; regions of, 597 ; viscera
of, 602
Abdominal aorta, 365, branches of, 367
surgical anatomy of, 367 ; muscles, 229
ring external, 230, 694, internal, 697
viscera, position of, 598
Abducens nerve, 479
Abductor minimi digiti muscle (hand), 266,
(foot), 300
Abductor i)ollicis muscle (hand), 264, (foot)
300
Aberrant duct of testis, 678
Absorbent glands, 426
Absorbents, 425
Accelerator uriuee muscle, 712
Accessory obturator nerve, 522; palatine
canals, 47 ; pudic artery, 379
Acervulus cerebri, 469
Acetabulum, 81
Acromial end of clavicle, fracture of, 269
Acromial nerves, 604 ; region, muscles of,
247 ; thoracic artery, 351
Acromian process, 89 ; fracture of, 269
Actions of muscles. See each group of
Muscles
Adductor brevis muscle, 282 ; longus muscle,
282; magnus muscle, 282; poUicis muscle
(hand), 266, (foot), 302
Aggregate glands, 608
Air cells, 657
Air tubes, 648
Alee of vomer, 50
Alar ligaments of knee, 176 ; thoracic
artery, 352
Alimentary canal, 582 ; subdivisions of, 582
Allantois, 666
Alveolar artery, 329 ; process, 43
Alveoli of lower jaw, 52 ; of upper jaw, 43 ;
formation of, 589 ; of stomach, 605
Amphiarthrosis, 136
Ampullae of semicircular canals, 577
Ampullse of tubuli lactiferi, 691
Amygdalae, 692 ; of cerebellum, 471
Anal fascia, 720
Analysis of bone, how conducted, 1
Anastomosis of arteries, 307
Anastomotica magna of brachial, 356, of
femora], 389
Anatomy, descriptive, 1 ; of femoral hernia,
700 ;_ of inguinal hernia, 692 ; study of, 1 ;
surgical, 1
Anconeus muscle, 261
Aneurisms of abdominal aorta, 367 ; of arch
of aorta, 312 ; of thoracic aorta, 364
Angle of jaw, 53 ; of pubes, 80 ; of rib, 73
Angular artery, 323 ; movement, 138 ; pro-
cess, external, 25 ; internal, 26 ; vein, 403
Animal constituent of bone, 1
Ankle joint, 178 ; arteries of, 394 ; bones of,
178; ligaments of, 178 ; relations of ten-
dons and vessels, in front, 179, behind,
179, 396
Annular ligament of radius and ulna, 1 63 ;
of wrist, anterior, 263 ; posterior, 263 ;
of ankle, anterior, 297 ; external, 298 ;
internal, 298 ; of stapes, 575
Annulus ovalis, 623
Anomalus muscle, 195
Anterior annular ligament (wrist), 263,
(ankle), 297 ; dental canal, 41 ; eth-
moidal cells, 38 ; fontanelle, 24 ; fossa
of skull, 55 ; nasal spine, 44 ; palatine
canal, 43, 68 ; palatine fossa, 43, 58 ; region
of skull, 62 ; triangle of neck, 330 ; crural
nerve, 522
Antihehx, 568 ; fossa of, 568
Antitragicus muscle, 569
Antitragus, 568
Antrum of Highmore, 41
Anus, 709 ; muscles of, 710, 715
Aorta, 309 ; abdominal, 365 ; abdominal
branches of, 367 ; abdominal, surgical ana-
tomy of, 367 ; arch of, 310 ; ascending
part of arch, 310; branches of, 313; de-
scending part of arch, 311 ; peculiarities
of arch, 312 ; peculiarities of branches of,
313; surgicalanatomy of, 312; transverse
portion of, 311 ; descending, 363 ; thora-
cic, 363 ; thoracic branches of, 364 ; sur-
gical anatomy of, 364
Aortic opening of diaphragm, 240 ; of heart,
635 ; plexus, 539 ; semilunar valves, 635 ;
sinuses, 635
Apertura iter chordae anterius, 671 ; pos-
terius, 571 ; scalte vestibuli et cochleae,
577
Aperture of larynx, 644; of posterior
nares, 60
Aponeurosis, 185 ; of deltoid, 247 ; of ex-
ternal oblique in inguinal region, 693 ;
infra spinous, 248 ; of insertion, 187 ; of
investment, 187; of occipito-frontalis, 190 ;
subscapular, 247 ; supra-spinous, 248 ;
vertebral, 222
722
INDEX.
Appendages of eje, 564 ; of skin, 545 ; of
uterus, 688
Appendices epiploicse, 602
Appendix of right auricle, 631; of left
auricle, 634; vermiformis, 609
Aqua labyriuthi, 579
Aqugeductus cochleae, 30,. $79 ; A^estibuli, 577 ;
Fallopii, 572 ; Sylvii, 468
Aqueous chamber, epithelial lining of, 556 ;
humour, 561 ; secreting membrane of,
562
Arachnoid of brain, 449 ; of cord, 443 ; struc-
ture of, 449
Arbor vitse uterimis, 687 ; vitte of cere-
bellum, 473
Arch of aorta, 310, peculiarities of, 312,
branches of, 313, surgical anatomy, 312;
of pubes, 83 ; of a vertebra, 5 ; supra-
orbital, 25 ; of colon, 611 ; crural or
femoral, 703 ; palmar superficial, 261 ;
palmar deep, 358 ; plantar, 398 ; zygo-
matic, 58
Arciform fibres of medulla oblongata, 454
Ai'eola of breast, 690
Arnold's ganglion, 493
Arteria centralis retinse, 561
Aryteno-epiglottidean folds, 644
ArytEeno-epiglottideus inferior muscle, 647 ;
superior, 647
Arytenoid cartilages, 642 ; glands, 648
Arytsenoideus muscle, 646
Arm, back of muscles of, 252 ; front of
muscles of, 250 ; arteries of, 352 ; bones
of, 91 ; fascia of, 250 ; nerves of, 509 ;
veins of, 410
Arnold's nerve, canal for, 30
Arteriae receptaculi, 334
Arteries, General Anatomy of, 307 ; anas-
tomoses of, 307 ; coats of, 308, external,
308, internal, 308, middle, 308 ; contrac-
tile coat of, 308 ; distribution of. 307 ;
epithehal lining of, 308 ; mode of divi-
sion, 307 ; mode of origin of branches,
307 ; nerves of, 308 ; physical properties
of, 308 ; sheath of, 308 ; structure of, 308 ;
subdivision of, 307 ; systemic, 307 ; tor-
tuosity of, 307 ; vessels of, 308
Arteries or Artery, Descriptive omd Sur-
gical Anatomy of, 307
accessory pudic, 379 ; acromial thoracic,
351 ; alar thoracic, 352 ; alveolar, 329 ;
anastomotica magna of brachial, 356,
of femoral, 389 ; angular, 323 ; anterior
cerebral, 338, choroid, 338, ciliary, 336,
564, communicating, 338, intercostal,
347, spinal, 344 ; aorta, 309, abdominal,
365, arch of, 310, ascending part, 310,
descending part, 311, 363, surgical ana-
tomy of, 312, transverse portion, 311,
thoracic, 363 ; articular, knee, superior
internal, 391, external, 391, inferior
internal, 392, external, 392 ; ascending
cervical, 345, pharyngeal, 325 ; audi-
tory, 344, 581 ; auricular anterior, 326,
posterior, 324 ; axillary, 349 ; azygos
of knee, 392
basilar, 344 ; brachial, 352, carpal an-
terior, 359 ; bronchial, 364 ; buccal,
329 ; of bulb, 715 ; bulbosi ure three,
380
Arteries or Artery {continued).
calcaneal internal, 397 ; carotid common,
315, external 319, internal 332 ; carpal
ulnar anterior, 363, posterior, 363 ; car-
pal radial anterior, 359, posterior, 359 ;
centralis retinae, 336; cerebellar anterior,
344, inferior, 344, superior, 344 ; cerebral
anterior, 338, middle, 338, posterior,
344 ; cervical ascending, 345, super-
ficial, 346, princeps, 348, profunda, 347 ;
choroid anterior, 338, posterior, 345 ;
ciliary, 336, anterior, 336, long, 336,
short, 339 ; circle of WiUis, 345 ; cir-
cumflex of arm anterior, 352, posterior,
352, of thigh external, 388, internal,
388, iliac, 384, superficial, 387 ; cochlear
381-'; coccygeal, 381 ; colica dextra, 371,
media, 372, sinistra, 373 ; coeliac axis,
367 ; comes nervi ischiadici, 381, phre-
nici, 347 ; common carotid, 315, iliac,
375, left, 376, right, 376 ; communi-
cating anterior cerebri, 338, posterior
cerebri, 338 ; communicating branch
of ulnar, 363; coronary of heart, 313,
of upper lip, 323, of lower lip, 323 ;
cremasteric, 384 ; crico-thyroid, 320 ;
cystic, 369
deep branch of ulnar, 363, cervical, 347,
palmar arch, 358, temporal, 328 ; de-
ferent, 378 ; dental inferior, 328, supe-
rior, 329; descending aorta, 363, pala-
tine, 329 ; digital plantar, 398 ; digital of
of ulnar, 363 ; dorsal of penis^ 380, of
scapula, 346 ; dorsalis hallucis, 395, in-
dicis, 359, linguEe, 321, pedis, 394, poUi-
cis, 359
epigastric, 383, superior, 347, superficial,
387 ; ethmoidal, 336 ; external carotid,
319, plantar, 397
facial, 321 ; femoral, 384, deep, 387 ;
frontal, 336
gastric, 367, 370 ; gastro-duodenalis, 368,
gastro-epiploica dextra, 369, gastro-epi-
ploica sinistra, 370 ; gluteal, 382, infe-
rior, 381
hehcine, 674 ; haemorrhoidal external, 380,
middle, 378, superior, 373 ; hepatic, 368 ;
hyoid branch of lingual, 321, of superior
thyroid, 320 ; hypogastric in foetus,
639, 640
ileo colic, 371 ; iliac, common external,
382, internal, 377 ; ilio-lumbar, 382 ;
inferior cerebellar, 344, dental, 328,
labial, 323, laryngeal, 320, mesenteric,
372, profunda, 356, pyloric, 369, thy-
roid, 345 ; infra-orbital, 329 ; innomi-
nate, 314 ; intercostal, 365, anterior, 347,
superior, 347; internal auditory, 581,
■ carotid, 332, ihac, 377, mammary, 346,
maxillary, 326, plantar, 397 ; inter-
osseous ulnar, 362, of foot, 395, of hand,
362, anterior, 362, posterior, 362 ; in-
testini tenuis,
labial inferior, 323 ; lachrymal, 335 ; la-
ryngeal, superior, 320 ; lateral saci'al,
382, spinal, 343 ; lateralis nasi, 323 ;
left common carotid, relations of, 315 ;
lingual, 320 ; long ciliary, 336, 563,
thoracic, 352 ; lumbar, 374
malleolar external, 394, internal, 394 ;
INDEX.
723
Arteries or Artery {contimied).
mammary internal, 346 ; mawseteric, 328;
maxillary internal, 327 ; median, 362 ;
mediastinal, 347, posterior, 364 ; me-
ningeal anterior, 327, middle, 334, small,
328 ; from occipital, 324 ; from pbarjm-
geal 325 ; from vertebral, 343 ; mesen-
teric inferior, 372, superior, 370 ;
metacarpal, 359 ; metatarsal, 395 ;
middle cerebral, 338, sacral, 375 ; mus-
culo-phx'enic, 347 ; mylo-hyoid,
nasal, 329 ; of ophthalmic, 336, lateral
of septum, 323 ; nutrient of humerus,
356, femur, 389, fibula, 397, radius, 362,
tibia, 397, ulna, 362
obturator, 378 ; occipital, 324 ; oesopha-
geal, 364 ; ophthalmic, 334 ; ovarian,
373
palatine, ascending, 322, descending, 329,
posterior, 329, of pharyngeal, 325 ; pal-
mar arch, superficial, 361, deep, 358 ;
palmar interossei, 360 ; palpebral, 336 ;
pancreatic, 370 ; pancreatico-duode-
nalis, 369, inferior, 370 ; perforating of
hand, 360, of thigh, 388, intercostal,
347 ; plantar, 398 ; pericardiac, 347, 364 ;
perinaeal superficial, 380, transverse, 381 ;
peroneal, 396, anterior, 397 ; pharyngea
ascendens, 325 ; phrenic, 374 ; popli-
teal, 390 ; posterior auricular, 324, ce-
rebral, 344, communicating, 338, menin-
geal from vertebral, 343, palatine, 329 ;
princei^s cervicis, 324, poUicis, 360 ;
profunda of arm, inferior, 356, superior,
355, cervicis, 347, femoris, 387 ; ptery-
goid, 328; pterygo-palatine, 329 ; pudic
external deep, 387, internal, 379, super-
ficial, 387 ; pulmonary, 399 ; pyloric
inferior, 369, of hepatic, 368
radial, 357, relations of in fore-arm,
357, relations of in the hand 358, sur-
gical anatomy of, 368 ; radialis in-
dicis, 360 ; ranine, 321 ; recurrent in-
terosseous posterior, 363, radial, 358,
ulnar anterior, 361, posterior, 361,
tibial, 323 ; renal, 373
sacral lateral, 382, middle, 375 ; scapular
posterior, 346; sciatic, 381 ; short ci-
liary, 336, 563 ; sigmoid, 373 ; sperma-
tic, 373 ; spheno-palatine, 329 ; spinal
anterior, 344, lateral, 343, posterior,
344, in neck, 343, in loins, 374, in
thorax, 365, median, 344 ; splenic, 369 ;
sterno - mastoid, 320 ; stylo - mastoid,
325 ; subclavian, 338, right, first part
of, 339, left, first part of, 339, second
portion of, 340, third portion of, 340,
surgical anatomy of, 341 ; sublingual,
321 ; submaxillary, 323 ; submental,
323 ; subscapular, 352 ; superficial cer-
vical, 340, circumflex iliac, 387, perinseal,
378, palmar arch, 361 ; superficialis vo-
Ise, 359 ; superior cerebellar, 344, epi-
gastric, 347, hsemorrhoidal, 373, inter-
costal, 347, laryngeal, 320, mesenteric,
370, profunda, 355, thoracic, 351,
thyroid, 320 ; supra-orbital, 335, supra-
renal, 373, supra-scapular, 345 ; sural,
391
tarsal, 394 ; temporal, 325, anterior, 325,
Arteries or Artery {contmued).
deep, 328, middle, 326, posterior, 326 ;
thoracic, acromial, 351, alar, 352,
aorta, 363, long, 352, superior, 351 :
thyroid axis, 345 ; thyroid inferior,
345, superior, 320 ; tibial, anterior, 392,
posterior, 395, recurrent, 393 ; tonsil-
litic, 323 ; transverse facial, 326 ;
transverse of basilar, 344 ; transversalis
colli, 346 ; tympanic, from internal
carotid, 334, from internal maxillary,
327
ulnar, 360, relations at wrist, 360, rela-
tions in fore-arm, 360, relations in the
hand, 361 ; recurrent, anterior, 361,
posterior, 361, umbilical in foetus, 639,
640 ; uterine, 378
vaginal, 378 ; vasa, aberrantia of arm,
354, brevia, 370, intestini tenuis, 370 ;
vertebral, 343 ; vesical, inferior, 378,
middle, 378, superior, 378 ; vestibular
581 ; Vidian, 329
ARTicuLATioisrs in general, 133
acromio-clavicular, 158 ; ankle, 178 ; as-
tragalo-calcaneal, 180, astragalo-sca-
phoid, 182 ; atlo-axoid, 141
calcaneo - astragaloid, 180, calcaneo-cu-
boid, 181, calcaneo - scaphoid, 181
carpo-me-"tacarpa], 168 ; carpal, 166
classificali(5^ of, 137; coccygeal, 155
costo-clavicular, 157; costo-sternal, 150
costo-transverse, 148 ; costo-vertehral,
147
elbow, 161
femoro-tibial, 172, of foot, 180
hand, 166 ; hip, 170
immoveable, 135
knee, 172
larynx, 643 ; lower limb. 170
metacarpal 169 ; metacai'po-phalangeal,
169 ; metatarso-j)halangeal, 184 ; meta-
tarsal, 183; mixed, 136; moveable, 136 ;
movements of, 138
occipito-atloid, 143 ; occipito-axoid, 144 ;
of pelvis, 153 ; pelvis with spine, 152 ;
phalanges, 170 ; pubic, 155
radio-carpal, 164 ; radio-ulnar, inferior,
164, middle, 156, superior, 163
sacro - coccygeal, 154; saci'o- iliac, 153;
sacro-sciatic, 154 ; sacro-vertebral, 152;
scapulo-clavicular, 158 ; scapulo-hume-
ral, 160; shoulder, 160; sterno- clavicu-
lar, 156 ; of sternum, 151
tarso-metatarsal, 183 ; tarsal, 180 ; tem-
poro-maxillary, 145; tibio-fibular, in-
ferior, 177, middle, 177, superior, 176 ;
of tympanic bones, 574
upper extremity, 156 ; of upper limb, 156
of vertebral column, 138
wrist, 164
Arytenoid cartilages, 642
Ascending colon, 611
Astragalus, 125
Atlas, 6 ; develoi^ment of, 12
Atlo-axoid articulation, 141
Atrabiliaiy capsules, 664
Attollecs aurem muscle, 190
Attrahens aurem muscle, 190
Auditory artery, 581 ; canal, cartilaginous
portion, 570; osseous portion, 570
? A 2
724
INDEX.
Auditory meatus, external, 29, internal, 30;
nerve, 477, 581 ; process, 30
Auricle of ear, 567 ; cartilage of, 568 ; liga-
ments of, 568; structure of, 568
Auricle of heart, left, 633 ; appendix of, 634;
sinus of, 634 ; right, 630 ; openings in,
631 ; valves in, 631 ; sinus of, 630
Auricular ai'tery posterior, 324, anterior,
326 ; fissure, 30 ; lymphatic glands, 428 ;
nerve, of vagus, 498, posterior from facial,
481 ; veins, anterior, 403, posterior, 404 ;
surface of sacrum, 14
Auricularis magnus nerve, 504
Auriculo-temporal nerve, 492
Auriculo-ventricular groove of heart, 630 ;
opening, left, 634, 635 ; opening right,
631, 632
Axes of the pelvis, 84
Axilla, 348 ; dissection of, 242
Axillary artery, 349 ; first portion of, 349 ;
second portion of, 350 ; third portion of,
350; peculiarities, 351 ; surgical anatomy
■ of, 351 ; branches of, 351 ; lymphatic
glands, 430 ; vein, 412
Axis, 7 ; cerebro-spinal, 439 ; cceliac, 367 ;
thyi'oid, 345
Azygos artery, articular, 392 ; vein, left, lower,
415 ; vein, right, 414 ; uvulse muscle, 214
Back, muscles of, first layer, 218 ; second
layer, 221 ; third layer, 222 ; fourth layer,
223, fifth layer, 227
Bartholine, duct of, 594
Base of brain, 457 ; of skull, external sur-
face, 55, internal surface, 55
Basilar artery, 344 ; process, 20 ; suture, 54
Basilic vein, 411, median, 411
Basio-glossus muscle, 210
Bauhin, valves of, 610
Beale, Dr., his researches on the liver, 618
Bend of elbow, 354
Berzelius, his analysis of bone, 1
Biceps muscle, 251, 288
Bicipital groove, 93
Bicus]3id teeth, 585
Biliary ducts, 620 ; glands of, 621 ; structure
of, 621
Biventer cervicis muscle, 226
Bladder, surgical anatomy of, 717 ; base of,
717 ; false ligaments of, 667 ; female,
relations of, 684 ; interior of, 667 ; liga-
ments of, 666 ; lymphatics of, 435 ; nerves
of, 668 ; shape, position, relations, 665 ;
structure of, 667 ; summit, body, base,
and neck of, 666 ; trigonum vesicaa of,
667 ; true ligaments of, 666 ; uvula vesicae
of, 668 ; vessels of, 668
Blood, circulation of, in adult, 630, in foetus,
638
Body of a tooth, 584 ; of a vertebra, 5
Bone, General Anatomy of: aftected with
rickets, analysis of, 2 ; animal constituent
of, 1 ; cancellous tissue of, 2 ; chemical
analysis of, 1 ; compact tissue of, 2 ;
diploe of, 3 ; development of, 3 ; earthy
constituent of, 1 ; general properties of, 1 ;
growth of, 4 ; inorganic constituent of,
1 ; lymphatics of, 3 ; medullary canal of,
2 ; medullary membrane of, 3 ; nerves of.
Bone {continued).
3 ; organic constituent of, 1 ; ossification
of, 4 ; spongy tissue of, 2 ; structure of
the extremities, 2, of the shaft, 2; veins of
3 i vessels of, 3
Bones, forms of, 2 ; flat, 3 ; irregulai', 4 ;
long 2 ; mixed, 3 ; short, 2
Bones or Bone, Descriptive Anatomy of, 1 ;
ankle, 178 ; astragalus, 125 ; atlas, 6 ;
axis, 7
calcaneum, 122 ; carpal, 102 ; carpus, 103 ;
clavicle, 84; coccyx, 16 ; cranial, 19, ar-
ticulations of, 53 ; cuboid, 124, cunei-
form of carpus, 103 ; of tarsus, 127
ear, 574 ; ethmoid, 37
facial, 19, 39 ; femur. 111; fibula, 120;
finger, 109 ; foot, 122 ; frontal, 24
hand, 102 ; humerus, 91 ; hyoid, 67
ilium, 76 ; incus, 574 ; inferior maxillary^
50, turbinated, 49 ; innominate, 76 ;
isciiium, 79
lachrymal, 44, lesser lachrymal, 45, lingual
67
magnum, 107 ; malar, 45 , malleus, 574 ;
maxillary, inferior, 50 ; metacarpus, 107 ;
metatarsal, 129
nasal, 39 ; navicular of carpus, 103, of
tarsus, 127, number of, 4
occipital, 19 ; orbicular, 574
palate, 46 ; patella, 116 ; parietal, 22 ;
pelvic, 76 ; phalanges, of foot, 130, of
hand, 109 ; pisiform, 105 ; pubic, 80
radius, 100 ; ribs, 71 : ribs, peculiar, 73
sacrum, 12 ; scaphoid of carpus, 103, of
tarsus, 127 ; scapula, 86 ; semilunar,
103 ; sesamoid, 131 ; sphenoid, 32 ;
sphenoidal spongy, 36 ; spongy, 49 ;
stapes, 574 ; sternum, 68 ; superior
maxillary, 40
tarsal, 122 ; temporal, 27 ; tibia, 116 ;
trapezium, 105 ; trapezoid, 105 ; tri-
quetral, 39 ; turbinate, superior, 38, in-
ferior, 49 ; tympanic, 31
ulna, 97 ; unciform, 107 ; ungual, 109
vertebra dentata, 7, iDrominens, 8 ; veite-
brse cervical, 5, dorsal, 8, lumbar, 10 ;
vomer, 50
Wormian, 39
Bostock's analysis of a rickety bone, 2
Bowman, on structure of kidney, 662
Brachia of o];)tic lobes, 469
Brachial artery, 352, branches of, 355, pecu-
liarities of, 354, surgical anatomy of, 354 ;
lymphatic glands, 430 ; plexus, 506,
branches above clavicle, 507, below cla-
vicle, 508 ; region, posterior, muscles of,
260, 261, anterior, 250
Brachialis anticus muscle, 252
Brain, 450 ; base of, 45 7 ; dura mater of,
447 ; interior of, 460 ; lateral ventricles
of, 463 ; lobe of, anterior, 457, middle
457, posterior, 4o7 ; membranes of, dissec'
tion, 447 ; subdivision into parts, 450 ;
upper surface of, 455 ; weight of, 450
Breasts, 690
Brim of Pelvis, 83
Broad ligaments, formation of, 600, of uterus,
686
Bronchi, right and left, 649, structure of in
lobules of lung, 656, in lung, 656
INDEX.
725
Bronchial arteries, 364, 657 ; lymphatic
glands, 438 ; veins, 415 ; tubes. See
Bronchi.
Bronchus, mode of subdivision in lung, 656
Brunner's glands, 60S
Bubonocele, 699
Buccal arteries, 329 ; glands, 583 ; lympha-
tic glands, 428 ; nerve, 491 ; veins, 403
Buccinator, muscle, 198
Bulb, artery of, 381, 715 ; of corpus caverno-
sum, 673 ; of corpus spongiosum, 673 j
olfactory, 476
Bulbi vestibuli, 683
Bulbous portion of urethra, 669
Bulbs of the fornix, 459
Bursse mucosae, 134
Bursal synovial membranes, 134
Caecum, 609
Calamus scriptorius, 472
Calcanean arteries, internal, 397
Calcaneo-astragaloid ligament, external, 180,
posterior, 181
Calcaneo-cuboid ligament, internal, 181,
superior, 181, long, 181, short, 181
Calcaneum, 122
Calicos of kidney, 662
Canals or Canal, accessory palatine, 47 ;
alimentary, 582 ; anterior dental, 41, pala-
tine, 58, 43 ; for Arnold's nerve, 30 ; audi-
tory, 570 ; carotid, 31 ; central of modio-
lus, 578 ; for chorda tympani, 571 ; of
cochlea, 578 ; crural, 705 ; dental posterior,
40 ; ethmoidal, anterior, 26, 55, posterior,
26, 56 ; femoral, 705 ; incisive, 43, 58 ; in-
ferior dental, 52 ; infra-orbital, 40 ;
inguinal, 696 ; for Jacobson's (tympanic)
nerve, 30, 61 ; lachrymal, 44 ; malar, 45
nasal, 44 ; naso-palatine, 50 ; of Nuck, 681
690 ; of Petit, 563 ; portal, 618 ; palatine
posterior, 41, anterior, 43 ; pteiygoid, 35
pterygo-palatine, 34 ; spermatic, 696
of spinal cord, 447 ; spiral of cochlea,
578 ; of modiolus, 578 ; semicircular, 677
for tensor tympani, 573 ; vertebral, 18
Vidian, 35 ; of Wirsung, 622
Canaliculi of eyelids, 567
Canalis spiralis modioli, 579
Cancellous tissue of bone, 2
Canine eminence, 40 ; fossa, 40 ; teeth, 585 ;
of lower jaw, 685 ; of upper jaw, 685
Canthi of eyelids, 664
Capillaries, 308
Capitula laryngis, 643
Caput coecum coli, 609 ; gallinaginis, 668
Capsular ligament of hip, 170 ; of knee, 174 ;
of shoulder, 160 ; of thumb, 168
Capsule of Ghsson, 617 ; of the lens, 562 ; of
lens, in foetus, 562 ; of Malpighian bodies
of kidney, 662
Capsules, suprarenal, 663
Cardiac lymphatics, 438 ; nerves, 536,
.inferior, 536, middle, 636, superior, 536 ;
nerves from pneumogastric, 499 ; plexus
of nerves, deep, 536, superficial, 637 ;
veins, 423, anterior, 423, great, 423, pos--
terior, 423
Carotid arteries, common, 316 ; artery, exter-
nal, 319, surgical anatomy, 319, internal,
Carotid Arteries {continued).
332, cervical portion, 332, petrous poiiion,
333, cavernous portion, 334, cereliral por-
tion, 334, sui-gical anatomy, 334 ; left,
common, relations of, 315, peculiarities of,
317, surgical anatomy of, 318 ; canal, 30 ;
ganglion, 634 ; plexus, 534, triangle infe-
rior, 330, triangle supeiior, 330
Carpal arteries, from radial, 359 ; from
ulnar, 363 ; ligaments, 166
Cai-po-metacarpal articulations, 168
Carpus, 102 ; development of, 110, articula-
tions of, 166
Cartilage or Cartilages, General Anatomy
of, 133 ; articular 133 ; arytenoid, 642 ; of
auricle, 568 ; of bronchi, 656 ; costal, 75 ;
cricoid, 642 ; cuneiform, 643 ; of ear, 568 ;
ensiform, 70 ; of epiglottis, 643 ; fibro, 133,
interarticular, 133, interosseous, 134, cir-
cumferential, 134, stratiform, 134j of larynx,
641, structure of, 643 ; of the nose, 660 ;
of the pinna, 568 ; of Santorini, 643 ;
semilunar of knee, 175 ; of septum of
nose, 551 ; tarsal, 564 ; temporary, 3 ;
thyroid, 641 ; of trachea, 650 ; of Wris-
berg, 643 ; xiphoid, 70
Cartilago triticea, 644
Caruncula lachrymalis, 566 ; mammillaris,
475
Caruuculse myrtiformes, 683
Cauda equina, 445, 524
Cava inferior, 420, peculiarities, 420 ; supe-
rior, 414
Cavernous body, artery of, 381 ; groove, 33,
67 ; nerves of penis, 541 ; plexus, 634 ;
sinus, 408
Cavities of reserve (teeth), 589
Cavity cotyloid, 81 ; glenoid, 89 ; of pelvis,
83 ; sigmoid, 97
Cells, ethmoidal, 38
Cement of teeth, 588 ; formation of,
590
Centres of ossification, 4
Centrum ovale majus, 461, minus, 461
Cephalic vein, 411
Cerato-glossus muscle, 210
Cerebellar arteries, anterior, 344, superior,
344, inferior 344 ; veins, 407
Cerebelli incisura, anterior, 470, posterior,
470
Cerebellum, 476 ; corpus dentatum of, 473 ;
hemispheres of, 470 ; laminse of, 473 ;
lobes of, 472 ; lobulus centralis of, 471 ;
median lobe ofj 470 ; peduncles of, 474 ;
structure of, 473 ; under surface of,
471 ; upper surface of, 470 ; the valley of,
471 ; ventricle of, 472 ; weight of,
470
Cerebral arteries, 338 ; anterior, 338, mid-
dle, 338, posterior, 344 ; convolutions,
455 ; lymphatics, 428 ; veins, 406 ; ven-
tricles, 463
Cerebro-spinal axis, 439, fluid, 444, 449 ;
nerves, 440
Cerebrum, base of, 457 ; commissures of
468 ; convolutions of, 455 ; crura of,
460 ; fibres of, 469 ; fissures, of Sylvius,
459, longitudinal, 455 ; general arrange-
ments of its parts, 460 ; grey mat-
ter of, 455 ; hemispheres ofj 455 ; in-
726
INDEX.
Cerebrum (continued).
terior of, 460 ; labia of, 461 ; lobes of,
457 ; peduncles of, 460 ; structure of,
469 ; sulci, 455, 456 ; superior ganglia of,
463, 467 ; under surface, 457 ; upper
surface, 455 ; ventricles of, 463
Cervical artery, ascending, 345, superficial,
346 ; ganglion inferior, 535, middle, 635,
superior, 534 ; lymphatic glands, deep,
429, superficial, 429 ; nerves, 502, anterior
branches of, 502, posterior branches of,
505, roots of, 602 ; plexus, 503, deep
branches of, 504, posterior, 606, superficial
branches of, 503 ; veins, transverse, 404 ;
vertebras, 5
Cervicalis ascendens muscle, 225
Cervico-facial nerve, 483
Cervix uteri, 686
Chambers of the eye, 561, 562
Check ligaments, 145
Cheek, muscles of, 197
Cheeks, 583 ; structure of, 583
Chemical analysis of bone, 1 ; of cerebro-
spinal fluid, 449 ; dentine or ivory, 587 ;
enamel, 588 ; of nervous substance, 439 ;
synovia, 135 ; thymus, 659 ; thyroid,
658
Chest, muscles of front, 243, side, 246
Chiasma or optic commissure, 476
Chondro-glossus muscle, 210
Chorda tympani nerve, 481, 576
Chordae tendinese, of right ventricle, 633,
of left, 635 ; vocales, 645 ; Willisii,
408
Choroid arteries, anterior, 338, posterior,
345 ; coat of eye, 557 ; plexus of lateral
ventricle, 464 ; of fourth ventricle, 473 ;
of third ventricle, 467 ; structure of,
557 ; veins of brain, 407
Chyli receptaculum, 427
Cilia or eyelashes, 565
Ciliary arteries, 336, anterior, 336, 564, long,
336, 663, short, 336, 563 ; ganglion, 487 ;
ligament, 569 ; muscle, 559 ; nerves, long,
487, short, 487 ; processes of eye, 658 ;
structure of, 558
Circle of Willis, 345
Circular sinus, 409
Circulation of blood in adult, 630 ; in foetus,
639
Circumduction, 138
Circumferential fibro-cartilage, 134
Circumflex artery of arm, anterior, 352,
posterior, 352 ; of thigh, external, 388,
internal, 388 ; ihac artery, 384, 692,
superficial, 387 ; iliac vein 419, superfi-
cial, 417 ; nerve, 609
Circumflexiis palati muscle, 214
Clavicle, 84 ; acromial end, fracture of, 269 ;
articulations of, 86 ; attachment of
muscles to, 86 ; development of, 86 ;
fracture of, 268 ; peculiarities, 86 ; sternal
end, fracture of, 269 ; structure of, B6 ;
tubercle of, 85
Clavicular nerves, 504
Clinoid j)rocesses, anterior, 32, 67, middle,
32, posterior, 33, 67
Clitoris, 683 ; frtenum of, 683 ; lymphatics
of, 436 ; muscles of, 714 ; prepuce of, 683 ;
structure of, 683
Coccygeal artery, 381 ; nerves, 524 ; nerve,
anterior branch of, 525, posterior branch
of, 624
Coccygeus muscle, 716
Coccyx, 16 ; articulations of, 17 ; attach-
ment of muscles to, 17 ; cornua of, 16 ;
development of, 17
Cochlea, 578 ; arteries of, 581 ; central axis
of, 678 ; cupola of, 678 ; denticulate
lamina of, 679 ; hamular process of, 579 ;
infundibulum of^ 578 ; lamina spiralis of,
579 ; membranous zone of, 579 ; nerves
of, 681 ; osseous zone of, 679 ; scala
tympani of, 679 ; scala vestibuli of, 679 ;
scalEe of, 679 ; spiral canal of, 678 ; veins
of, 581 ^
Cochlear artery, 581 ; nerve, 681
Cochlearis muscle, 579
Cceliac axis, 367 ; plexus, 539
Colica dextra artery, 371, media, 372, si-
nistra, 373
Colles fracture, 272
CoUiculus bulbi urethree, 673
Colon, 611
Columella cochleae, 678
Columnae camete of left ventricle, 635, of
right ventricle, 633 ; papillares, 635,
633
Columns of abdominal ring, 694 ; of me-
dulla oblongata, 451 ; of rectum, 613 ;
of spinal cord, 446 ; of vagina, 686
Columnar layer of retina, 560
Comes 'nervi ischiadici artery, 381 ; phrenici
artery, 347
Commissura simplex of cerebellum, 471
Commissure of flocculus, 472 ; optic, 476
Commissures, 439 ; of brain anterior, 468,
middle or soft, 468, posterior, 468 ; of,
spinal cord, grey, 446, white, 445
Communicans noni nerve, 505
Communicating artery of brain anterior
338, posterior, 338
Compact tissue of bone, 2
Complexus muscle, 226
Compressor narium minor, 195 ; nasi, 195 ;
sacculi laryngis, 647 ; urethras, 715
Conarium, 468
Concha, 568
Condyles of bones. See Bones
Condyloid foramina, 20 ; fossse, 20 ; process,
53 ; veins posterior, 408
Congenital hernia, 699
Conglobate glands, 426
Coni vasculosi, 678
Conjoined tendon of internal oblique and
transversalis, 232, 695
Conjunctiva, 666
Conoid ligament, 158
Constrictor inferior muscle, 211 ; medius,
212 ; superior, 212 ; isthmi faucium, 210 ;
iirethrse, 715
Conus arteriosus, 632
Convolution of corpus callosum, 456 ; of
longitudinal fissure, 457 ; supra-orbitar,
457
Convolutions of cerebrum, structure of,
455 ; cortical substance of, 455 ; white
matter of, 455
Coraco-acromial ligament, 159 ; coraco-
brachialis muscle, 251 ; coraco-clavicular
INDEX.
727
Coraco-acromial {continued).
ligameut, 158 ; coraco-humeral ligament,
l(jO
Coracoid ligament, IGO ; process, 90 ; pro-
cess, fracture of, 209
Cord spermatic, 676
Cordiform tendon, 240
Corium of skin, 543
Cornea, 555 ; arteiies and nerves of, 556 ;
elastic laminae of, 555 ; proper substance
of, 555 ; structure of, 555
Cornicula laryngis, 643
Cornu Ammonis, 465
Cornua of the coccyx, 16 ; of hyoid bone,
68 ; of the sacrum, 13 j of thyroid car-
tilage, 642
Corona giandis, 672
Coronal suture, 54
Coronary arteries of lip, 323 ; arteries of
heart, left, 313, right, 313 ; peculiari-
ties, 314 ; ligaments of liver, 614; plexus,
anterior, 537, posterior, 537 ; sinus, 423,
opening of, 631 ; valve, 632
Coronoid dejjression, 94 ; process, 53, of
ulna, 97, fracture of, 271
Corpora albicantia, 459 ; Arantii, 633, 635 ;
cavernosa penis, 673, crura of, 673, struc-
ture of, 673 ; cavernosa clitoridis, 683 ;
geuiculata, 469 ; mammillaria, 459 ; oliva-
ria, 452 ; pyramidalia, 451 ; quadrige-
mina, 469 ; restiformia, 452 ; striata, 463,
veins of, 407
Corpus callosum, 458, 461, convolution of,
456, genu of, 462, peduncles of, 458,
ventricle of, 461 ; deutatum of cerebel-
lum, 473 ; of olivary body, 453 ; fim-
briatum, 464, 465 ; Highmorianum, 677 ;
luteum, 689, structure of, 689 ; spongio-
sum, 673, arteries of, 674, colliculi bulbi,
673, structure of, 674
Corpuscles, Malpighiau, of kidney, 662 ; of
spleen, 625
Corrugator supercilii muscle, 191
Cortical substance of brain, 439 ; of cere-
bral convolutions, 455 ; of kidney, 660 ;
of supra-renal capsules, 664
Costal cartilages, 75
Costo-clavicular ligaments, 157 ; costo-cora-
coid fascia, 244 ; costo- sternal articula-
tion, 150 ; costo-transverse articulation,
148 ; costo-vertebral ligaments, 147 ;
costo-xiphoid ligaments, 151
Cotyloid cavity, 81 ; ligament, 171 ; notch, 81
Coverings of direct inguinal hernia, 699, of
femoral hernia, 707 ; of oblique, 698 ; of
testis, tunica albuginea, 677, tunica va-
ginalis, 677, tunica vasculosa, 677
Cowper's glands, 672, 715
Cranial bones, 191, articulations of, 53 ;
Cranial Nerves, 475, classification of,
475, first pair, 475, second, 476, third
477, fourth, 478, fifth, 485, sixth, 479,
seventh, soft portion, 477, hard portion,
480, eighth, glosso-pharj'ugeal, 494 ; vagus,
497; spinal accessory, 496, ninth, 483
Cranial sutures, 53
Cremaster muscle, 695, formation of, 696
Cremasteric artery, 676 ; fascia, 675
Crest, frontal, 25 ; of ilium, 78 ; nasal, 40 ;
occipital, 20, internal, 58 ; turbinated of
Crest {continued).
palate, 47 ; ot superior maxillary, 42, 43 ;
of pubes, 80 ; of tibia, 118
Cribriform fascia, 702 ; plate of ethmoid, 37
Crico-aryta)noideus lateralis muscle, 646,
posticus muscle, 646
Crico-thyroid artery, 320 ; membrane, 644 ;
muscle, 046
Cricoid cartilage, 642
Crista galli, 37; ilii, 78; pubis, 80
Crown of a tooth, 584
Crucial ligaments of knee, 174, 175
Crura cerebri, 460, structure of, 460 ; of
corpora cavernosa, 673 ; cerebelli, 474 ;
of clitoris, 683 ; of diaphragm, 239 ; of
fornix, 466
Crurseus muscle, 280
Crural arch, 694, 703, deep, 705 ; canal,
705 ; nerve anterior, 522 ; ring, 706 ;
sheath, 704
Crusta petrosa of teeth, 588
Crypts of Lieberkiihn, 608
Crystalline lens, 562
Cuboid bone, 124
Cuneiform bone, hand, 103, foot, external,
128, internal, 127, middle, 128 ; cai'tilages,
643
Cupola of cochlea, 578
Curling, Mr., on the development of the
testes, 681
Curvatures of the spine, 17
Cuspidate teeth, 585
Cutaneous branches of musculo-spiral, 515,
of ulnar nerve, 513 ; nerve, of arm ex-
ternal, 509, internal, 510, lesser internal,
510, of buttock and thigh, 528, of in-
guinal region, 692, of ischio-rectal region,
710, fi'om obturator, 522, from peroneal,
530, of thigh external, 520, of thigh in-
ternal, 523, of thigh middle, 522, of
thorax lateral, 517 ; of plantar nerve, 529
Cuticle of skin, 543
Cutis vera, 542
Cystic artery, 369 ; duct, 620, valve of,
620 ; plexus of nerves, 539 ; veins, 423
Dartos, 675
Decussation of optic nerves, 467 ; of pyra-
mids, 451
Deciduous teeth, 584
Deep crural arch, 705 ; palmar arch, 358 ;
perinaeal fascia, 715
Deltoid aponeurosis. 247 ; muscle, 247
Dens sapieutite, 586
Dental artery, inferior, 328 ; canal, anterior,
41, inferior, 52, posterior, 40 ; follicles,
589 ; groove, 589 ; nerves anterior, 4 89,
inferior, 493, posterior, 489 ; pulps, 590 ;
sacs, 589, structure of, 590 ; tubuli, 587 ;
vein, inferior, 403
Denticulate lamina of cochlea, 579
Dentine, 5b7, chemical composition of, 587 ;
formation of, 590
Depressions for Pacchionian bodies, 55
Depressor alse nasi, 195 ; auguli oris, 197;epi-
glottidis muscle, 647 ; labii inferioris, 197
Derma, or true skin, 542
Descending aorta, 363 ; colon, 611
Descendens noni nerve, 484
728
INDEX.
Descent of testicle, 680
Development of atlas, 12 ; axis, 12
bone, 3
carpus, 110 ; clavicle, 86 ; coccyx, 17
ethmoid, 38
femur, 115 ; fibula, 122 ; foot, 130 ;
frontal bone, 27
hand, 110 ; humerus, 95 ; hyoid bone, 68
inferior turbinated bone, 50
lachrymal bone, 45 ; lower jaw, 53 ; lum-
bar vertebrse, 12
malar bone, 46; metacarpus, 110; meta-
tarsus, 131
nasal bone, 40
occipital bone, 22 ; os innominatum,
82
palate bone, 49 ; parietal bone, 24 ; pa-
tella, 116; permanent teeth, 589 ;
phalanges of hand, 110, of foot, 131
radius, 102; ribs, 75
sacrum, 15 ; scapula, 91 ; seventh cervical,
12 ; sphenoid, 36 ; sternum, 70 ; supe-
rior maxillary bone, 44
tarsus, 130 , temporary teeth, 588 ; tem-
poral bone, 31 ; tibia, 120
ulna, 100
vertebrae, 11 ; vomer, 50
Diameters of pelvis, 83
Diaphragm, 238 ; lymphatics of, 438
Diaphysis, 4
Diarthrosis, 136 ; rotatorius, 126
Digastric muscle, 207 ; fossa, 29 ; nerve, from
facial, 481
Digestion, organs of, 582
Digital arteries from ulnar, 363, plantar,
398 ; cavity of lateral ventricle, 463 ;
fossa, 112 ; nerves from median, 511, from
ulnar, 514
Dilator naris, anterior, 195, posterior, 195
Diploe, 3 ; veins of, 405
Direct inguinal hernia, 699, comparative
frequency of, 700, course of, 699, coverings
of, 699, diagnosis of, 700, incomplete,
700
Dissection of abdominal muscles, 229 ; arch
of aorta, 310 ; arm, 250 ; auricular re-
gion, 190
back, 288
epicranial region, 188 ; eye, 556
femoral hernia, 700 ; face, 191 ; foot, 298;
fore-arm, 253
gluteal region, 283
hand, 188; head, 263 ; heart, left auricle,
634, left ventricle, 635, right auricle, 631,
right ventricle, 632 ; hernia, 692,
700
inferior maxillary region, 196 ; infra-hyoid
region, 205 ; inguinal hernia, 692 ;
ischio-rectal region, 709
lingual region, 209 ; leg, 289
neck, 202
orbit, 192
palatal region, 213 ; palm of hand, 263 ;
palpebral region, 191 ; pancreas, 621 ;
pectoral region and axilla. 242 ; peri-
naeum, 709 ; pharynx, 211 ; pterygoid
muscles, 200
radial region, 258
sole of foot, 298 ; spinal cord and mem-
branes, 442 ; supra-hyoid region, 207
Dissection {continued).
temporal muscle, 199 ; thigh, front of,
276, back of, 288, internal, 281
Dorsal artery of penis, 380 ; nerves, 516,
anterior branches of, 516, peculiar, 517,
posterior branches of, 516, 1'oots of, 516 ;
vertebrae, 8, peculiar, 9
Dorsales pollicis arteries, 359
Dorsalis hallucis artery, 395, indicis, 359,
linguae, 321, pedis, branches of, 394, pecu-
liarities of, 394, surgical anatomy of, 394
Dorsum of scapula, 86
DtrcTS OR Duct, of Bartholine, 594 ; bihary
620 ; of Cowper's glands, 672 ; cystic, 620
ejaculatory, 680 ; galactophorous, 691
hepatic, 620 ; of kidney, 662 ; lactiferous
690 ; of iiver, 618 ; lymphatic, right, 428 '
nasal, 567 ; of pancreas, 622 ; parotid, 593
Stenonian, 593 ; thoracic, 426 ; Whar-
tonian, 594
Ductless glands, 657, 663
Ductus arteriosus, 638 ; how obhterated in
foetus, 640, communis choledocus, 620 ;
pancreaticus minor, 622; Riviniani, 594 ;
venosus, 639, how obliterated, 640
Duodenal glands, 608
Duodenum, 606 ; vessels and nerves of, 607
Dura mater of brain, 447, arteries of, 448,
nerves of, 448, processes of, 448, structure
of, 448, veins of, 448 ; of cord, 443, pecu-
liarities of, 443
Ear, 567 ; arteries of, 325 ; auditory canal,
570 ; cochlea, 578 ; internal or labyrinth,
576 ; membranous labyrinth, 580 ; mus-
cles of, 190 ; ossicula of, 574 ; pinna or
auricle of, 567 ; semicircular canals, 577 ;
tympanum, 576 ; vestibule, 576
Earthy constituent of bone, 1
Ecker, on supra-renal capsules, 664
Eighth pair of nerves, 494
Ejaculatory ducts, 680, structure of, 680
Elbow, bend of, 354 ; joint, 161 ; vessels and
nerves of, 162
Eminence of aqueductus Fallopii, 572 ; ca-
nine, 40 ; frontal, 25 ; ilio-pectineal, 80 ;
jugular, 20 ; nasal, 27 ; parietal, 22
Eminentia articularis, 27 ; coUateralis, 463,
465
Enamel of teeth, 588 ; chemical composition
of, 588 ; formation of, 590 ; membrane,
590 ; organ, 590 ; rods, 588
Enarthrosis, 136
Endocardium, 635
Endolymph, 581
Ensiform appendix, 68, 70
Epidermis, 543, development of, 544 ; growth
of, 544 ; structure of, 544
Epididymis, 676
Epigastric artery, 383, peculiarities, 384,
relation to femoral ring, 705, with in-
ternal ring, 698, superficial, 387, 692 ;
superior, 337 ; plexus, 538 ; region, 598 ;
vein, 419, superficial, 417
Epiglottis, 643
Epiphyses, separation of, 4
Epithelium. See various Organs.
Erectile tissue, its structure, 674 ; of penis,
674 ; of vulva, 683
INDEX.
729
Erector clitoridis, 713 ;penis,713; spiuEe,223
Eruption of the teeth, 590
Ethmo-sphenoidal suture, 55
Ethmoid bone, 37, articulations of, 39, cri-
briform plate of, 37, development of, 38,
lateral masses of, 38, perpendicular plate
of, 37, OS planum ofj 38, unciform process,
of, 38
Ethmoidal artery, 336 ; canal anterior, 20,
55, posterior, 2t>, 56 ; cells, 38 ; notch, 26 ;
process of inferior turbinated, 49 ; spine, 32
Ethmoido-frontal suture, 55
Eustachian tube, 573, tympanic orifice of,
573 ; valve, 631, in foetal heart, 637
External abdominal ring, 694 ; annular liga-
ment, 298 ; inguinal hernia, 698 ; orbitar
foramina, 35 ; pteryoid plate, 35
Extensor brevis digitorum muscle, 299;
carpi radialis brevior, 239, longior, 258 ;
carpi ulnaris, 260 ; communis digitorum
(hand), 260 ; indicis, 262 ; longus digito-
rum (foot), 291 ; minimi digiti, 260 ; ossis
metacarpi pollicis, 261 ; primi internodii
pollicis, 261 ; proprius pollicis, 291 ; se-
cundi internodii pollicis, 262
Eye, 553 ; appendages of, 564 ; cham-
bers of, 561, 562 ; ciliary ligament, 559,
muscle, 559, processes of, 558 ; hu-
mours of, 554, 561, aqueous, 561, crys-
talhne lens, 562, vitreous, 562 ; mem-
brana pupillaris, 559, choroid, 557, con-
junctiva, 566, cornea, 555, hyaloid, 562,
iris, 558, Jacob's, 560, retina, 559, sclerotic
554; pupil of, 558; tunics of, 554; uvea
of, 559 ; vessels of globe of, 563
Eyeball, muscles of, 192, nerves of, 564,
veins of, 564
Eyebrows, 564
Eyelashes, 565
Eyelids, 564, cartilages of, 564, Meibomian
glands of, 565, muscles of, 191, structure
of, 564, tarsal ligament of, 564
Eye teeth, 585
Face, arteries of, 323 ; boaes of, 39, 62 ;
lymphatics of 428 ; muscles of, 196 ;
nerves of, 482 ; veins of, 403
Facial artery, 321, transverse, 326 ; bones,
19, 39 ; nerve, 480, branches of, 481, its
communications, 480, course of, in tem-
poral bone, 480 ; vein, 402
Falciform process of fascia lata, 703
Fallopian tubes, 688 ; fimbriated extremity
of, 688 ; lymphatics of, 436 ; nerves of,
690 ; structure of, 688 ; vessels of, 690
False corpora lutea, 689 ; ligaments of blad-
der, 667 ; pelvis, 82 ; ribs, 72 ; vertebrae,
5, 12
Falx cerebelli, 449 ; cerebri, 448
Fangs of teeth, 584
Fascia or Fascia, 185, 186 ; anal, 720 ;
aponeurotic, its structure, 187 ; of arm,
250
cervical, deep, 203, superficial, 202 ; costo-
coracoid, 244 ; cremasteric, 675, 696 ;
cribriform, 702
deep, 186 ; dentata, 465 ; dorsal, of foot, 299
fibro-areolar, its structure, 186 ; of foot,
297 ; of fore-arm, 253
FAScryE OR Fascia {continued)
of hand, 263
iliac, 274 ; infundibuliforrn, 697 ; inter-
columnar, 231, 694, 695 ; intercostal,
237 ; intermuscular of arm, 251, of
thigh, 277, of foot, 298 ; ischio-rectal,
723
lata, 277, 702, falciform process of, 703,
iliac portion, 702, pubic portion, 703 ;
of leg, 289 ; lumborum, 233
of mamma, 242
of neck, 201
obturator, 720
palmar, 264 ; pelvic, 719 ; perinseal, deep,
715, superficial, 711 ; plantar, 298 ;
propria, 675
recto-vesical, 720
spermatic, 694, superficial, 711, 186, of
head, 188, of inguinal region, 692, of
ischio-rectal region, 710, perinseal, 711,
of thigh, 276, of upper extremity, 241,
246
temporal, 199 ; of thorax, 236, 242 ;
trans versalis, 696 ; of trunk, 217
Fasciculi graciles, 452, teretes, 453, 472
Fasciculus unciformis, 459
Fauces, isthmus of, 592
Female Organs op Generation ; bulbi
vestibuli, 684 ; carunculse myrtiformes,
683 ; clitoris, 683 ; fossa navicularis, 683 ;
fraenulum pudendi, 683 ; glands of Bar-
tholine, 683 ; hymen, 683 ; labia majora,
683, minora, 633 ; nymphas, 683 ; preepu-
tium clitoridis, 683 ; uterus, 686 ; vagina,
685 ; vestibule, 633
Femoral arch, 703, deep 705 ; artery, 384 ;
branches of, 387, peculiarities of, 386,
surgical anatomy of, 386, deep femoral,
387
canal, variation in size of, according to
position of hmb, 707
hernia, complete, 707 ; coverings of, 707 ;
cutaneous vessels and nerves of, 700 ;
descent of, 707 ; dissection of, 700 ; in-
complete, 707 ; seat of stricture, 708 ;
superficial fascia, 700 ; surgical anatomy
of, 700 ; varieties of, 707
ligament (Hey's), 703
region, muscles of anterior, 276, internal,
281, posterior, 288 ; ring, 705, position
of surrounding parts, 705
sheath, 704
vein, 418 ; relation to femoral ring, 705
Femur, 111, articulations of, 115, attach-
ment of muscles to, 115, development of,
115 ; fracture of above condyles, 305,
below trochanters, 304 ; neck, fracture of,
304
Fenestra ovalis, 571 ; rotunda, 572
Ferrein, pyramids of, 662 ; tubes of, 662
Fibrse arciformes, 452, transversse, 473
Fibrine of muscle, 185
Fibro-cartilage, 133 ; circumferential, 134 ;
inter-articular, 133 ; inter-osseous, 134 ;
stratiform, 134
Fibro-cartikges, acromio-clavicular, 159; in-
tervertebral, 139, of knee, 175; of lower jaw,
146; pubic, 156; radio-ulnar, 164; sacro-
coccygean, 155, sterno-clavicular, 157
Fibula, 120; articulations of, 122; attach-
7Z^
INDEX.
Fibula {continued).
ment of muscles to, 122 ; development
of, 122 ; fracture of, with dislocation of
the tibia, 306
Fibular region, muscles of, 296
Fibrous rings of heart, 636
Fifth nerve, 485 ; ventricle of brain, 465
Fimbria of Fallopian tube, 688
Fissura palpebrarum, 564
Fissure, auricular, 30, horizontal of cere-
bellum, 472 ; of ductus venosus, 615 ; for
gall-bladder, 616 ; Glaserian, 28, 571 ; of
liver, 615 ; longitudinal of liver, 615 ;
longitudinal of cerebrum, 455, 457 ; of
lung, 655 ; maxillary, 41 ; of medulla
oblongata, 451 ; portal, 615 ; pterygo-maxil-
lary, 62 ; sjDheno-maxillary, 62 ; sj^henoidal,
35, 57 ; of spinal cord, anterior lateral,
445, median, 445, posterior laterfil, 445,
median, 445 ; Sylvian, 459 ; transverse, of
liver, 615, of cerebrum, 465 ; umbilical,
615 ; for vena cava, 616
Flat bones, 3
Flexor accessorius muscle, 301 ; brevis digi-
torum, 300 ; brevis minimi digiti (hand),
266, (foot), 302 ; brevis poUicis (hand),
265, (foot), 302 ; carpi radialis, 255, ul-
naris, 255 ; digitorum sii olimis, 255 ;
digitorum profundus, 256 ; longus digito-
rum, 295; longus poUicis (hand), 257,
(foot), 294; ossis metacarpi pollicis,
264
Floating ribs, 72
Flocculus, 472
Foetus, circulation in, 639, Eustachian valve
in, 637 ; foramen ovale in, 637 ; liver of,
distribution of its vessels, 639 ; ovaries
in, 690 ; relics in heart of, 632 ; vascular
system in, peculiarities, 637
Folds, ary teno - epiglottidean, 644 ; recto-
uterine, 600; recto-vesical, 630 ; vesico-
uterine, 600
Follicle of hair, 545
Follicles sebaceous, 546
Follicular stage of development of teeth, 589
Fontanelle, anterior, 24 ; posterior, 21
Foot, bones of, 122 ; development of 130 ;
dorsum, muscles of, 299 ; fascia of, 297 ;
sole of, muscles of, 299, nerves of, 529,
530, vessels of, 394, 398
Foramen, csecum, 25, 55, of frontal bone,
25, of medulla oblongata, 451, of tongue,
547; carotid, 30 ; condyloid, 20 ; dental
inferior, 52 ; incisive, 58 ; infra-orbital,
40 ; intervertebral, 1 8 ; lacerum anterius,
35, 57, medium, 57, postering, 58 ; mag-
num, 20, 58 ; mastoid, 29 ; mental, 51 ;
of Monro, 466 ; obturator, 81 ; optic, 32,
35 ; ovale of heart, 637, of sphenoid, 34, 57 ;
palatine anterior, 43, posterior, 47 ; jDa-
rietal, 23 ; pterygoid, 60 ; pterygo-pala-
tine, 60 ; rotundum, 34, 57 ; sacro-sciatic,
great, 79, small, 80 ; of Soemmering, 560 ;
spheno-palatine, 49 ; spinosum, 34, 57 ;
sternal, 70 ; stylo-mastoid, 30 ; supra-or-
bital, 25 ; thyroid, 81 ; vertebral, 5 ; Ves-
ahi, 34, 57 ; of Winslow, 600
Foramina, sacral, 12 ; of diaphragm, 240 ;
external orbitar, 35 ; malar, 46; olfactory,
37 ; Thebesii, 631
Foi'e-arm, fascia of, 253 ; muscles of, 253,
vessels, 357, nerves of, 511, bones of, 97
Foreskin, 672
Form of bones, 2
Fornix, 466 ; bulbs of, 459 ; crura of, 466
Fossa, of antihehx, 568 ; canine, 40; condy-
loid, 20 ; cystis felleee, 616 ; digastric, 29 ;
digital, 112; glenoid, 28; of helix, 568 ;
iliac, 78 ; infra and supra spinous, 86 ;
incisive, 40, 51 ; innominata, 568 ; ischio-
rectal, 710; jugular, 61 ; lachrymal, 26 ;
myrtiform, 40 ; navicular of urethra, 669,
of vulva, 683 ; occipital inferior, 58 ;
ovalis, 632 ; palatine anterior, 43, 58 ;
pituitary, 32, 57 ; j)terygoid of sphenoid,
35, of lower jaw, 53 ; scaphoid, 35 ; sca-
phoidea, 568 ; spheno-maxillary, 62 ; of
skull, anterior, 55, middle, 57, posterior,
57 ; subscapular, 86 ; sublingual, 51 ; sub-
maxillary, 52 ; temporal, 61 ; trochan-
tei'ic, 112; zygomatic, 62
Fossse, nasal, 65, 552
Fourchette, 683
Fourth nerve, 478 ; ventricle, 472
Fovea ceu trails retinae, 560 ; hemispherica,
577 ; hemi-elhptica, 577
Fracture of acromian process, 269
centre of clavicle, 268, acromial end of,
269 ; coracoid process, 269 ; coronoid
process of ulna, 271
femur above condyles, 305, below tro-
chanters, 304 ; fibula, with dislocation
of tibia, 306
humerus, anatomical lieck, 269, shaft of,
270, surgical neck, 269
neck of femur, 304
olecranon process, 271
patella, 305
radius, 271, lower end of, 272, neck of,
271, shaft of, 272, and ulna, 272
sternal end of clavicle, 269 ; tibia, shaft of,
305
ulna, shaft of, 272
Frcena of ileo-coecal valve, 610
Frsenulum cerebri, 469; pudendi, 683; of
Vieussen's valve, 469
Frgenum clitoridis, 683 ; labii superioris et
iuferioris, 582 ; preputii, 672
Frontal artery, 336 ; bone, 24, articulations
of, 27, attachment of muscles to, 27, deve-
lopment of, 27, structure of, 27; crest, 25 ;
eminence, 25 ; nerve, 486 ; process of
malar, 45 ; sinuses, 26 ; suture, 27, 55 ;
vein, 403
Fronto-malar suture, 65
Fronto-sphenoidal suture, 55
Fundus of uterus, 686
Funiculi of nerve, 440
Funiculus, 440
Furrow, auriculo-ventricular, 630 ; interven-
tricular, 630
Furrowed band of cerebellum, 471
Galactophorous ducts, 691
Gall bladder, 619 ; fissure for, 616 ; struc-
ture of, 620 ; valve of, 620
Ganglia, General Anatomy and Structure
of, 440 ; cardiac, 537 ; cephalic, 487 ; of
fifth nerve, 487 ; lumbar, 540 ; lymphatic,
INDEX.
731
Ganglia {continued).
426 ; mesenteric, 539 ; renal, 538 ; sacral,
540 ; semilunar of abdomen, 538 ; solar,
538 ; of spinal nerves, 501 ; of sym-
pathetic nerve, 532, branches from, 532 ;
thoracic, 537
Ganglion, Arnold's 493 ; of 'Andersch, 495
carotid, 534 ; cervical, inferior, 535, mid-
dle, 535, superior, 534 ; ciliary, 487 ;
on circumflex nerve, 509
diaphragmatic, 535
on facial nerve, 480
Gassenan, 485 ; glosso-pharyngeal, 495
impar, 540 ; inferior cervical, 535 ; inter-
carotid, 535 ; on posterior interosseous
nerve, 515
jugular, 495, 497, 498
lenticular, 487 ; lingual, 535
Meckel's, 489 ; middle cervical, 535
ophthalmic, 487 ; otic, 493
petrous, 496 ; pharyngeal, 535 ; pneumo-
gastric, 498 ; of portio dura, 480
of Kibes, 532 ; root of vagus, 498
semilunar, 485 ; spheno-palatine, 489 ;
submaxillary, 494 ; superior cervical,
534 ; supra-renal, 538
temporal, 535 ; thyroid, 535 ; trunk of
vagus, 498
of Wrisberg, 537
Ganglionic branch of nasal nerve, 486
Gasserian ganglion, 485
Gastric arteries (vasa brevia), 370 ; artery,
367 ; follicles, 605 ; nerves from vagus,
500 ; plexus, 539 ; vein, 422
Gastro-colic omentum, 601
Gastro-duodenal artery, 368 ; plexus, 539
Gastro-epiploica dextra artery, 369, sinistra,
370
Gastro-ejjiploic plexus, 539 ; vein leit, 422
Gastro-hepatic omentum, 599, 601
Gastro-phrenic ligament, 603
Gastro-splenic omentum, 601
Gastrocnemius muscle, 292
Gemellus inferior muscle, 287, superior,
287
Generativs Organs, female, 682, male, 671
Genial tubercles, 51
Genio-hyo-glossus muscle, 209
Genio-hyoid muscle, 208
Genito-crural nerve, 520
Genu of corpus callosum, 462
Gimbernat's ligament, 230, 695, 704
Ginglymus, 136
Gladiolus, 70, 68
Gland or Glandp, secreting, accessory of
parotid, 593 ; aggregate, 608 ; aryte-
noid, 648
of Barthohne, 683 ; of biliary ducts, 621 ;
Brunner's, 608 ; buccal, 583
ceruminous, 571 ; Cowper's 672, 715
duodenal, 608 ; ductless, 623
epiglottic, 648
gastric, 605
of Havers, 134
kidney, 660
labial, 582 ; lachrymal, 566 ; of larynx,
648 ; lingual, 549 ; of Littr6, 669 ;
liver, 613 ; lymphatic, 426
mammary, 690 ; Meibomian, 565 ; molar,
583 ; mucilaginous of Havers, 134
Gland or Glands {continued).
oesophageal, 5i)7
of Pacchioni, 448 ; palatine, 591 ; pancreas,
621 ; parotid, 592 ; peptic, 605 ; Peyer's,
608 ; pharyngeal, 595 ; pineal, 468 ;
pituitary, 459 ; prostate, 671
salivary, 592 ; sebaceous, 546 ; solitary,
608 ; sublingual, 594 ; submaxillary,
594 ; sudoriferous, 546 ; supra-renal,
663
thymus, 658 ; thyroid, 657 ; tracheal, 650 ;
of Tyson, 672
uterine, 687
of vulva, 683
Glands Ductless, 623 ; spleen, 623 ; supra-
renal, 663 ; thymus, 658 ; thyroid, 657
Glands Lymphatic, General Anatomy of,
426, conglobate, 426 ; axillary, 430 ; bron-
chial, 438 ; cervical, 429 ; iliac, 434;
inguinal, 432; intercostal, 437; lumbar,
435 ; mediastinal, 437 ; mesenteric, 437 ;
oesophageal, 438 ; popliteal, 433 ; sacral,
435 ; thoracic, 437
Glandulse odoriferse, 672 ; Pacchioni, 448
Glans penis, 672 ; clitoridis, 683
Glaserian fissure, 28, 571
Glenoid cavity, 89 ; fossa, 28 ; ligament,
160
Gliding movement, 138
Glisson's capsule, 601, 617
Globus major of epididymis, 676, minor,
676
Glosso-epiglottidean ligaments, 643
Glosso-pharyngeal nerve, 494
Glottis, 644 ; rima of, 645
Gluteal artery, 382, inferior, 381 ; lymphatic
glands, 433 ; nerve inferior, 526, superior,
525 ; region, lymphatics of, 435, muscles
of, 283 ; veins, 419
Gluteus maximus muscle, 283, medius, 284,
minimus, 285
Gomphosis, 136
Graafian vesicles, 689 ; membrana granulosa,
of, 689 ; ovicapsule of, 689 ; structure of,
689
Gracilis muscle, 281
Granular layer of retina, 560
Granular lids, 566
Great omentum, 600, 601 ; cavity of, 600 ;
sciatic nerve, 528
Greater wings of sphenoid, 34
Grey matter of cerebellum, 473 ; of fourth
ventricle 473, of third, 468 ; of medulla
oblongata, 454 ; of spinal cord, 440 ;
of cerebrum, 439, chemical analysis 439
Groin, cribriform fascia of, 702 ; cutaneous
vessels and nerves of, 700 ; region of, 700 ;
superficial fascia of, 700 ; surgical ana-
tomy of, 700
Groove, auriculo-ventricular, 630 ; bicipital,
93 : cavernous, 33, 57 ; dental, 589 ; infra-
orbital, 41 ; lachrymal, 43 ; mylo-hyoid,
52 ; nasal, 40 ; occipital, 29 ; optic 32, 57 ;
subclavian, 85
Grooves in the radius, 102 ; ventricular,
630
Growth of bone, 4
Gubernaculum testis, 68 L
Gums, 583
Gustatory nerve, 492
732
INDEX.
Gyri operti, 459
Gyrus fornicatus, 457
Haemorrhoidal artery, external, 380, middle,
378, superior, 373 ; nerve, inferior, 52(3 ;
plexus of nerves, 540 ; veins, inferior, 419,
middle, 419, superior, 419 ; venous plexus,
419
Hairs, follicles of, 545, structure of, 545 ;
medulla of, 546 ; root of, 545, sheath of,
546 ; shaft of, 546
Ham, region of the, 389
Hamstring tendons, surgical anatomy of,
289
Hamular process of sphenoid, 35 ; of cochlea,
579 ; of lachrymal, 45
Hand, bones of, 102 ; development of, 110;
fascia of, 263 ; muscles of, 263, 264 ; nerves
of, 511, 513, 514, 515; vessels of, 359,
363 ; ligaments of, 166
Hard palate, 591
Harmonia, 135
Havers glands of, 134
Head, muscles of, 188 ; veins of, 402
Head of scapula, 89 ; of ulna, 100
Heart, 629 ; annular fibres of auricles, 636 ;
arteries of, 637
circular fibres of, 637
endocardium, 635
fibres of the auricles, 636, of the ventricles,
636 ; fibrous rings of, 636 ; foetal relics
in, 632
left auricle, 633, ventricle, 635 ; looped
fibres of auricles, 636 ; lymphatics of,
438, 637
muscular structure of, 636
nerves of, 536, 537, 637
openings in right A^eutricle, 632
position of, 629
right auricle, 630, ventricle of, 632
septum ventriculoiaim, 632 ; size and
weight, 629 ; spiral fibres of, 637 ; struc-
ture of, 636 ; subdivision into cavities,
629
veins of, 637 ; vortex of, 637
Helicine arteries, 674
Helicis major muscle, 569, minor, 569
Helicotrema of cochlea, 579
Helix, 568 ; fossa of, 568 ; muscles of, 569 ;
process of, 568
Hepatic artery, 368, 617, 619 ; cells, 618 ;
duct, 617, 620; plexus, 539 ; veins, 42],
617, 618, 619
Hernia congenital, 699 ; direct inguinal,
699 ; femoral, coverings of, 707, descent
of, 707, dissection of, 700, varieties of,
707 ; infantile, 699 ; inguinal, 692, dissec-
tion of, 692 ; oblique inguinal, 698 ; scro-
tal, 699
Hesselbach's triangle, 699
Key's ligament, 703
Hiatus Fallopii, 30, 57
Highmore, antrum of, 41
Hilton's muscle, 647
Hilus of kidney, 660 ; of spleen, 623
Hip joint, 170 ; muscles of, 283
Hippocampus major, 465, minor, 463
Horizontal plate of palate, 46
Humerus, 91 ; anatomical neck, fracture of,
269 ; articulations of, 95 ; attachment of
muscles to, 95 ; development of, 95 ; head
of, 91 ; neck of, 91 ; nutrient artery of,
356 ; shaft of fracture of, 270 ; surgical
neck, fracture of, 269 ; tuberosities of,
greater and lesser, 91
Humours of the eye, 561
Hyaloid membrane of eye, 562
Hymen, 683
Hyo-epiglottic ligament, 644
Hyo-glossal membrane, 550
Hyo-glossus muscle, 210
Hyoid artery of superior thyroid, 320 ;
bone, 67, attachment of muscles to, 68,
cornua of, 68, development of, 68 ; branch
of lingual artery, 321 ; region, muscles of,
infra, 205, supra, 207
Hypochondriac regions, 598
Hypogastric arteries in fretus, 639, 640, how
obliterated, 640 ; "plexus, 540, infex'ior,
540 ; region, 598
Hypoglossal nerve, 483
Ileo-coecal or ilio-colic valve, 610
Ileo-colic artery, 371
Ileum, 607
Iliac arteries, common, 375, left, 376, right,
376, peculiarities, 376, surgical anatomy
of, 376 ; external, 382, surgical anatomy
of, 383 ; internal, 377, peculiarity in the
foetus, 377, at birth, 377, surgical anatomy
of, 377 ; fascia, 274 ; fotsa, 78 ; lymphatic
glands, external, 434, internal, 434 ; region,
muscles of, 274 ; vein, common, 419,
peculiarities ofj 420 ; external, 419, inter-
nal, 419
Iliacus muscle, 275
Ilio-femoral ligament, 171
Ilio-hyi3ogastric nerve, 519
Ilio-inguinal nerve, 520
Ilio-lumbar artery, 382, vein, 419
Ilio-pectineal eminence. 80
Ilium, 76 ; crest of, 78 ; dorsum of, 76
Impressio colica, 616 ; renalis, 616
Incisive canal, 43, 58 ; foramina, 58 ; fossa,
40,51
Incisor teeth of lower jaw, 585, of upper, 585
Incisura intertragica, 568
Incus, 574 ; ligament of, 575, suspensory, 576
Infantile hernia, 699
Inferior dental canal, 52 ; maxillary bone,
50 ; meatus of nose, 67 ; occipital fossa, 58 ;
profunda artery, 356 ; turbinated bones;
49, articulations of, 50, development of,
50, ethmoidal larocess of, 49, lachrymal,
process of, 49 ; vena cava, opening of,
631
Infra-costal muscles, 237
Infra-orbital canal, 40 ; foramen, 40 ; groove,
41
Infra-spinatus muscle, 249
Infra-spinous aponeurosis, 248
Infra-trochlear nerve, 487
Infundibula of kidney, 662
Infundibulifonn fascia, 697
Infundibulum of brain, 459 ; of ethmoid, 38 ;
of cochlea, 578 ; of heart, 632
INDEX.
733
Inguinal canal, COG ; glands, deep, 433,
superficial, 432, 701 ; hernia, 698, direct,
699, incomplete, 699, oblique, 698, surgical
anatomy of, 69iJ ; region, 598 ; dissection
of, 692
Inlet of pelvis, 83
Innominate artery, 314, peculiarities of, 314,
surgical anatomy of, 314 ; bone, 76, articu-
lations of, 82, attachment of muscles to,
82, development of, 82 ; veins, 412, pecu-
liarities of, 413
Inorganic constituent of bone, 1
luterarticular tibro-cartilage, 133, of sca-
pulo-clavicular joint, 159 ; of jaw, 146,
of pubes, 156, of radio-ulnar joint, 164,
of sterno- clavicular joint, 157 ; ligament
of ribs, 148
Intercarotid ganglion, 535
Interclavicular ligament, 157
Intercolumnar fascia, 231, 675, 694 ; fibres,
694
Intercondyloid notch 114
Intercostal arteries, 365, anterior, 347, su-
perior, 347 ; fascite, 237 ; ligaments, 151 ;
lymphatics, 437 ; lymphatic glands, 437 ;
muscles, 237 ; nerves, 516, lower, 517,
upper, 516 ; spaces, 72 ; veins, superior,
414
Intercosto-humeral nerve, 517
Interlobular, biliary plexus, 618 ; veins, 619
Intermaxillary suture, 58
Internal abdominal ring, 697 ; annular liga-
ment, 298 ; carotid artery, 332 ; cutaneous
nerve, 510 ; inguinal hernia, 698 ; oblique
muscle, 695 ; occipital crest, 58 ; pteryoid
plate, 35 ; sphincter, 710
Internasal suture, 63
Interossei muscles, dorsal of hand, 267, of
foot, 303, palmar, 268 ; plantar, 303
Interosseous artery, 262, anterior, 362,
posterior, 362 ; fibro-cartilage, 134 ; liga-
ment of radio-ulnar joint, 163 ; nerve,
anterior, 611, posterior, 515
Interpeduncular space of brain, 459
Interspinales muscles, 228
Interti'ansversales muscles, 228
Intervertebral notches, 5 ; substance, 139
Intestine, large, 609
Intestine, small, 606
Intralobular veins, 619
Intumescentia ganglio-formis, 480
Involuntary muscles, 185
Iris, 558 ; arteries of, 559; structure of, 559
Irregular bones, 4
Ischiatic lymphatic glands, 433
Ischio-rectal fascia, 720 ; fossa, 710, position
of vessels and nerves in, 711 ; region,
surgical anatomy of, 709
Ischium, 79 ; body of, 79 ; ramus of, 80 ;
spine of, 79 ; tuberosity of, 80
Island of Eeil, 459
Isthmus of the fauces, 592 ; of thyroid
gland, 658
Iter ad infundibulum, 468 ; a tertio ad
quartum ventriculum, 468
Ivory of tooth, 587
Jacob's membrane, 560
Jacobson's nerve, 576 ; canal for, 30
Jaw, lower, 50 ; development of, 53 ; articu-
lations of, 53, ligaments of, 145, attacli-
meut of muscles to, 53, oblique line of,
51, pterygoid fossa of, 53 ; rami of, 50;
symphysis of, 51
Jejunum, 607
Jouit. i:See Articulations.
Jugular foramen, 58 ; fossa, 61 ; ganglion,
495, 497, 498 ; process, 20 ; vein, anterior,
404, external, 404, external posterior, 404,
internal, 405, sinus or gulf of, 405
Kidney, 660 ; calyces of, 662 ; cortical sub-
stance of, 660 ; ducts of, 662 ; hilus of ,660 ;
infundibula of, 662 ; lymphatics of, 436,
663 ; Malpighian bodies of, 662 ; mammillaj
of, 661 ; medullary substance, 6 il ; nerves
of, 663 ; papillae of, 661 ,• pelvis of, 662 ;
pyramids of Ferrein, 662 ; relations of,
660 ; renal artery, 662 ; sinus of, 660, 662 ;
tubes of Ferrein, 662 ; tubuli uriniferi,
661 ; veins of, 662 ; weight and dimen-
sions, 660
Knee-joint, 172
Kiirschner, on structure of heart's valves, 662
Labia cerebri, 461 ; pudendi, majora, 682,
minora, 683, lymphatics of, 435
Labial artery, 323 ; glands, 582 ; veins, su-
perior, 403, inferior, 403
Labyrinth, 576 ; arteries of, 581 ; fibro-sei'ous
membrane of, 579 ; membranous, 580
Lachrymal apparatus, 566 ; artery, 335
bones, 44, articulations of, 45, attachment
of muscles to, 45, development of, 45
canals, 44, 566 ; caruncula, 566 ; fossa.
26 ; gland, 566 ; groove, 43 ; nerve, 486
papilla, 567, 564 ; process of inferior tur-
binated bone, 49 ; puncta, 664 ; sac, 667
tubercle, 43
Lacteals, 426, 437
Lactiferous ducts, 690
Ijacuna magna, 669
Lacus lachrymalis, 564
Lambdoid suture, 54
Lamella, horizontal of ethmoid, 37 ; perpen-
dicular of ethmoid, 37
Lamina cinerea, 458 ; ciibrosa of sclerotic,
655 ; fusca, 656 ; spiralis of cochlea, 579,
membranacea, 579
Laminse of cornea, elastic, 555 ; of the ver-
tebras, 6
Laminated tubercle of cerebellum, 472
Large intestine, 609 : cellular coat, 613 ;
csecum, 609 ; colon, 611 ; ilio-caecal valve,
610 ; mucous coat, 613 ; muscular coat,
612; rectum, 611; structure of, 612;
serous coat of, 612
Laryngeal artery, inferior, 320, superior, 320 ;
nerve, external, 498 ; internal, 499, recur-
rent, 499, superior, 498 ; from sympathetic,
535 ; pouch, 646 ; veins, 405
Laryngis sacculus, 646
Laryngo-tracheotomy, 651, 662
Laryngotomy, 651
Larynx, 641 ; actions of muscles of, 647 ;
arteries of, 648 ; cartilages of, 641 ; cavity
of, 644; glands of, 648; glottis, 644'; in-
734
INDEX.
Larynx (continned).
tei'ior of, 644 ; ligaments of, 643 ; lym-
phatics of, 648 ; mucous membrane of,
648 ; muscles of, 646 ; nerves of, 648 ;
rima glottidis, 645 ; veins of, 641 ; ventricle
of, 646 ; vocal cords of, false, 645, true, 645
Lateral ginglymus, 136 ; ligaments of liver,
614 ; masses of ethmoid, 38 ; region of
skull, 61
Lateralis nasi artery, 323
Latissimus dorsi muscle, 220
Laxator tympani major muscle, 575 ; minor,
575
Leg, muscles of. 289 : back of, 292 ; front of,
290 ; fascia of, 289, deep, 294
Lens, 562; changes produced in, by age, 563 ;
structure of, 563 ; suspensory ligament of,
563
Lenticular ganglion, 487
Lesser lachrymal bone, 45 ; omentum, 601,
599 ; sciatic nerve, 526 ; wings of sphe-
noid, 35
Levator anguli oris, 196, scapulae, 221 ;
ani, 715 ; glandules thyroidge, 658 ; labii
inferioris 196, superioris alseque nasi, 195 ;
superioris proprius, 196 ; palati, 213; pal-
pebrse, 192 ; prostatse, 716
Levatores costarum, 238
Lieberkiihn, crypts of, 60S
Ligaments, structure of, 134; acromio-cla-
vicular, superior and inferior, 158 ; alar
of knee, 176 ; of ankle, anterior, 178,
lateral, 179 ; annular of radius, 163,
of wrist, anterior, 263, posterior, 263,
of ankle, 297, external, 298, internal, 298,
of stapes, 575; anterior of knee, 173;
arcuate, 239 ; aryteno-epiglottic, 644 ;
astragalo-scaphoid, 182 ; atlo-axoid an-
terior, 141, posterior, 141
of bladder, false, 667, true, 666
calcaneo-astragaloid external, 180, poste-
rior, 180, interosseous, 180 ; calcaneo-
cuboid, internal, 181, long, 181, short,
181, superior, 181 ; calcaneo-scaphoid,
inferior, 182, superior, 181 ; capsular of
hip, 170, of jaw, 146, of knee, 174, of
shoulder, 160, of vertebrge, 141 ; carpo-
metacarpal, dorsal, 168, interosseous,
168, palmar, 168 ; of carpus, dorsal,
166, 167, interosseous, 167, palmar, 166,
167 ; central of spinal cord. 444 ; ciliary
of eye, 659 ; common vertebral ante-
rior, 138, posterior, 139; conoid, 158;
coraco-acromial, 152 ; coraco-clavicular,
158; coraco-humeral, 160; coracoid,
160; coronary of liver, 614 ; costo-cla-
vicular, 157 ; costo-sternal, anterior, 150,
posterior, 151 ; costo-transverse, ante-
rior, 148, middle, 149, posterior, 149 ;
costo- vertebral, or stellate, 147 ; costo-
xiphoid, 151 ; cotyloid, 171 ; crico-
arytenoid, 644 ; crico-thyroid, 644 ; cru-
cial of knee, 174, 175 ; cruciform, 143
deltoid, 178 ; dorsal of carpus, 166, meta-
carpus, 169, tarsus, 180, metatarsus,
183, tarso-metatarsal, 183
of elbow, 161 ; anterior, 161, external
lateral, 162, internal lateral, 162, poste-
rior, 162
falciform of liver, 614
Ligaments (co7itinued)
femoral (Hey's), 703
gastro-phrenic, 603 ; Gimbernat's, 230,
695, 704 ; glenoid, 160 ; glosso-epiglot-
tidean, 643
of hip, 170 ; hyo-epiglottic, 644
ilio-femoral, 171 ; ilio-lumbar, 152 ; of
incus, 675 ; interarticular of ribs, 1 48 ;
interclavicular, 157 ; intercostal, 151 ;
interosseous, calcaneo-astragaloid, 180,
calcaneo-cuboid internal, 181, carpal,
166, 167, carpo-metacarpal, 168, meta-
carpal, 169, metatarsal, 183, posterior,
sacro-iliac, 153, radio-ulnar, 163, of ribs,
149, tarsal, 110, tarso-metatarsal, 183,
tibio-fibular, inferior, 177 ; interspinous,
141 ; intertransverse, 141 ; interverte-
bral, 139
of jaw, 145, lateral external, 146, lateral
internal, 146
of knee, 172
of larynx, 643 ; lateral of bladder, 666 ;
of knee, 173, of liver, 614, of elbow, 161,
of carpus, 167, of ankle, 178, of jaw, 146,
longitudinal of liver, 614 ; long plantar,
181 ; lumbo-iliac, 152 ; lumbo-sacral, 152
metacarpo - phalangeal, 169; metacarpal,
169; metatarsal, 183; metatarso-pha-
langeal, 184; mucosum of knee, 176
nuchse, 220
oblique, 163; obturator, 156; occipito-
atloid, anterior, 143, lateral, 144, poste-
rior, r 144 ; occipito-axoid, 1 44 ; odon-
toid, 144; orbicular, 163; of ossicula,
574 ; of ovary, 690
palpebral or tarsal, 564 ; of patella. 173 ;
of pelvis, 153 ; of the phalanges, hand,
170, foot, 184 ; of the pinna, 568 ; plan-
tar, long, 181 ; i^osterior of knee, 173 ;
posticum Winslowii, 173 ; Poupart's,
230, 694, 703 ; pterygo-maxillary, 198 ;
pubic anterior, 155, posterior, 155, su-
perior, 155; pubo-prostatic, 666
radio-carpal, 1 64 ; radio-ulnar joint, in-
ferior, 164, middle, 163, superior, 163;
recto - uterine, 6S6 ; rhomboid, 157;
round of uterus, 690, of liver, 615, of
radius and ulna, 16 3, of hip, 171
sacro-coccygeal, anterior, 155, posterior,
155; sacro-iliac, anterior, 153, oblique,
154, posterior, 153 ; sacro-sciatic, greater,
154, lesser, 154; sacro-vertebral, 152;
of scapula, 159 ; of shoulder, 160; stel-
late, 147; steruo-clavicular, anterior and
posterior, 147 ; of sternum, 151 ; stylo-
maxillary, 146 ; sub-flavous, 140 ; sub-
pubic, 155 ; supra-spinous, 141 ; sus-
pensory of incus, 575, of lens, 563, of
liver, 614, of maUeus, 575, of mamma,
242, of penis, 672, of spleen, 623
tarsal of eyelids, 565
tarso-metatarsal, 183; of tarsus, 180;
teres of hip, 171 ; thyro-arytenoid, in-
ferior, 646, superior, 645; of thumb,
168; tibio-tarsal, 178; thyro-epiglottic,
644; thyro-hyoid, 644; tibio-hbular,
176; transverse of atlas, 142, of hip,
172, of knee, 175, of scapula, 160 ;
trapezoid, 158; triangular of urethra,
695 ; of tympanic bones, 574, of in-
INDEX.
735
Ligaments {continued).
cus, 57.5, of malleus, 575, of stapes, 575,
of urethra, 715
of uterus, 686
of vertebras, 138 ; vesico-uterine, 686
of wrist, anterior, 166, lateral external,
166, lateral internal, 166, posterior, 166
of ZiNN, 193
Ligamenta subflava, 140
Ligamentum, arcuatum externum, 239, in-
ternum, 239 ; denticulatum, 444 ; latum
l^ulmonis, 653 ; nuchas, 220; patellee, 173
Ligature of arteries. See each Artery.
Limbus luteus, 560
Linea alba, 236 ; aspera, 113; ilio-pectinea,
_78, 80, 82; quadrati, 113; splendens, 444
Linese semilunares, 236 ; transverste of abdo-
men, 236 ; transversse of fourth ventricle,
473
Lingual artery, 320 ; surgical anatomy of,
321 ; bone, 67 ; ganglion, 535 ; nerve, 492 ;
veins, 405
Lingualis muscle, 210
Lips, 582, structure of, 582; arteries of,
323
Liquor Cotunnii, 579 ; Morgagni, 562 ; Scar-
pee, 581 ; seminis, 680
Lithotomy, parts concerned in operation of,
717, avoided in operation, 718, divided,
718
Liver, changes of position in, 614 ; distribu-
tion of vessels to in foetus, 639 ; ducts of,
618 ; fibrous coat of, 617; fissures of, 615 ;
hepatic artery, 6 1 7, 6 1 9 ; hepatic cells, 618;
hepatic duct, 617 ; hepatic veins. 617, 618,
619; ligaments of, 614, lateral, 614, coro-
nary, 614, round, 615, longitudinal, 614;
lobes of, 616; lobules of, 617; lympha-
tics of, 436, 617 ; nerves of, 617; portal
vein, 617; situation, size, and weight, 613 ;
structure of, 617 ; its surfaces and borders,
614; vessels of, 617
Lobes of cerebrum, 457 ; of cerebellum, 472 ;
of liver, 616, left, 616, lobus caudatus, 617,
quadratus, 617, Spigelii, 617 ; of lung, 655 ;
of prostate, 671 ; of testis, 678 ; of thy-
roid, 657 ; of thymus, 658
Lobular bihary plexus, 618
Lobule of the ear, 568
Lobules of liver, 617 ; of lung, 656
Lobuli testis, 678
Lobulus caudatus, 617; centralis of cerebel-
lum, 471 ; quadratus, 617 ; Spigehi, 617
Locus cceruleus, 472 ; niger, 460 ; perforatus
anterior, 459, posterior, 460
Long bones, 2
Long saphenous nerve, 523
Longissimus dorsi muscle, 225
Longitudinal fissure, of brain, 457 ; of liver,
615, ligament of liver, 614
Longus colli muscle, 216
Lower extremity, arteries of, 384 ; bones of,
111 ; lymphatics of, 432 ; hgaments of,
170 ; muscles of, 273 ; nerves of, 520 ;
veins of, 417
Lower, tubercle of, 631
Lumbar arteries, 374 ; fascia, 233 ; ganglia,
540 ; glands, 435 ; nerves, 518, anterior
branches of, 518, posterior, 518, roots of,
518 ; plexus of nerves, 518, branches of,
Lumbar {continued).
519 ; region, 598 ; vein ascending, 420 ;
veins, 420 ; vertebra;, 10, development of,
12
Lumbo-iliac ligament, 152
Lumbo-sacral ligament, 152
Lumljricales muscles, hand, 267, foot, 301
Lungs, 654 ; air-cells of, 657 ; bronchial
arteries, 657, veins, 657 ; capillaries of,
657 ; iu foetus, ()39 ; lobes and fissures of,
655 ; lobr.les of, 656 ; lymphatics of, 438,
657 ; nerves of, 657 ; pulmonary artery,
657, veins, 657 : root of, 655 ; structure
of, 656 ; weight, colour, etc., 656
Lunulae of nails, 545
Lymphatic duct, right, 428
Lymphatic Glands, General Anatomy of,
426
Descriptive Anatomy :
anterior mediastinal, 437 ; auricular pos-
terior, 428 ; axillary, 430
brachial, 430 ; bronchial, 438 ; buccal, 428
in front of elbow, 430
gluteal, 4? 3
iliac, external, 434, internal, 434 ; inguinal,
deep, 433, superficial, 432 ; interccstal,
437 ; internal mammary, 437 ; ischiatic,
433
of large intestine, 437 ; of lower extremity,
432 ; lumbar, 435
of neck, 428
occipital, 428
parooid, 428 ; of pelvis, 434 ; popliteal, 433
radial, 430
sacral, 435 ; of small intestine, 437 ; of
spleen, 437 ; of stomach, 436 ; sub-
maxillary, 428
of thorax, 4.37 ; tibial anterior, 433
ulnar, 430 ; of upper extremity, 430
zygomatic, 428
Lymphatics, General Anatomy of, 425, coats
of, 425 ; origin of, 425 ; plexus of, 425 ; sub-
division into deep and superficial, 425 ;
valves of, 426 ; vessels and nerves of, 426 ;
where found, 425
Descriptive Anatomy:
abdomen, 435 ; arm, 431
bladder, 435 ; bone, 3 ; broad ligament.?, 437
cerebral, 428 ; cervical, superficial and
deep, 428 ; of clitorLs, 435 ; of cranium,
428
diaphragm, 431
face, superficial, 428, deep, 428 ; Fallopian
tubes, 436
gluteal region, 435
head, superficial, 428 ; heart, 438
intercostal, 437 ; internal mammary, 437 ;
intestines, 437
kidneys, 436
labia, 4.35 ; large intestine, 437 ; leg, 433 ;
liver, 436 ; lower extremity, 433 ; lung,
438 ; lymphatic duct,
meningeal, 428 ; mesentery, 437 ; mouth,
428
neck, 429 ; nose, 428 ; nymphse, 435
oesophagus, 438 ; ovaries, 436
pancreas, 437 ; pelvis, 435 ; penis, 435 ;
peringeum, 435 ; pharynx, 428 ; pia ma-
ter, 428 ; prostate, 435
rectum, 435
736
INDEX.
Lymphatics (continued).
scrotum, 435 ; small intestine, 437 ; spleen,
437 ; stomach, 436
testicle, 436 ; thoracic duct, 426 ; thorax,
437 ; thymic, 438 ; thyroid, 438
upper extremity, superficial, 431, deep,
432 ; uterus, 435
vagina, 436
Lyra of fornix, 466
Macula cribrosa, 577
Magnum of carpus, 107
Malar bone, 45, articulations of, 46, attach-
ment of muscles to, 46, development of,
46, frontal process of, 45, maxillary pro-
cess of, 46, orbital process of, 45 ; canals,
45 ; process, 43
Male urethra, 668
Malleolar arteries, external and internal, 393
Malleolus, external, 120, internal, 119
Malleus, 574 ; suspensory ligament of, 575
Malpighian bodies of kidney, 662 ; corpuscles
of spleen, 625, relation with arteries, 625
veins, 625
Mamma, areola of, 690 ; lobules of, 691 ;
nerves of, 691 ; nipple or mammilla of,
690 ; structure of, 691 ; vessels of, 691
Mammary artery, internal, 346; glands,
690 ; lymphatic glands, 437 ; veins, inter-
nal, 414
Mammilla of breast, 690 ; of kidney, 661
Manubrium of sternum, 68 ; of malleus, 574
Masseter muscle,, 198
Masseteric arteries, 328; nerve, 491; veins, 403
Masto-occipital suture, 54
Masto-parietal suture, 54
Mastoid cells, openings of, 572 ; foramen,
29 ; portion of temporal bone, 29 ; pro-
cess, 29 ; vein, 404
Matrix of nail, 545
Maxillary artery, internal, 326 ; bone, infe-
rior, 50, superior, 40 ; fissure, 41 ; nerve,
inferior, 491, superior, 487 ; process of
inferior turbinated, 49, of malar bone, 46 ;
sinus, 42 ; tuberosity, 40
Meatus auditorius externus, 29, 570, internus
30 ; of nose, inferior, 67, middle, 66, su-
perior, 66; urinarius, male, 669, female,
683
Meatuses of the nose, 66
Meckel's ganglion, 489
Median artery of fore-arm, 362; of spinal
cord, 344 ; nerve, 511 ;vein, 411
Mediastinal arteries, from internal mammary,
347, posterior, from aorta, 364 ; lymphatic
glands, 437
Mediastinum, anterior, 653 ; middle, 654 ;
posterior, 546 ; testis, 677
Medulla Oblongata, 451 ; anterior pyra-
mids of, 451, 452 ; back of, 452 ; fissures of,
451, grey matter of, 454; lateral tract, 452,
453 ; olivary body, 452, 453 ; posterior
pyramids, 452 ; restiform bodies, 452, 453 ;
septum of, 454 ; structure of, 452
Medulla spinalis, 435
Medullary canal of bone, 2, membrane, of
bone, 3 ; substance of brain, 439, of kid-
ney, 661, of supra-renal capsules, 664 ;
velum posterior of cerebellum, 472
Meibomian glands, 565
Membrana fusca, 555 ; granulosa, 689 ; limi-
tans, 561; nictitans, 566 ; pupillaris, 559 ;
sacciformis, 164 ; secundarii, 572, struc-
ture of, 573 ; tympani, 573
Membrane, of aqueous chamber, 562 ; arach-
noid, spinal, 443, cerebral, 449 ; choroid,
557 ; costo-coracoid, 244 ; crico-thyroid,
644 ; fenestrated, 308 ; hyaloid, 562 ; Ja-
cob's, 560 ; limiting, 561 ; pituitary, 552 ;
pupillary, 559 ; thyro-hyoid, 643 ; Schnei-
derian, 552
Membranes of Spinal Cord, 442 ; of brain,
447
Membranous labyrinth, 580, structure of,
580 ; portion of urethra, 669 ; semicir-
cular canals, 580
Meninges, cerebral, 447, spinal, 442
Meningeal artery, from ascending pharyn-
geal, 325, anterior, from internal carotid,
334 middle, from internal maxillary, 327,
from occipital, 324, posterior from ver-
tebral, 343, small, from internal maxillary,
328 ; lymphatics, 428 ; veins, 403
Menisci, 133
Mental foramen, 51 ; process, 51
Mesenteries, 600, 601
Mesenteric artery, inferior, 372, superior,
370 ; glands, 437 ; plexus of nerves, in-
ferior, 539, superior, 539 ; vein, inferior,
421, superior, 421
Mesentery, 601
Meso-ceeeum, 602, 609
Meso-colon, ascending, 602, descending, 602,
transverse, 600, 602
Meso-rectum, 602
Mesorchium, 681
Metacarpal artery, 359 ; articulations, 169
Metacarpo-phalangeal articulations, 168
Metacarpus, 107; common characters of,
108 ; development of, 110 ; peculiar bones
of, 108
Metatarsal articulations, 183; bones, 129
Metatarsea artery, 395
Metatarso-phalangeal articulations, 184
Metatarsus, 129, development of, 131
Middle clinoid processes, 32 ; ear, or tym-
panum, 571 ; fossa of skull, 57 ; meatus,
66
Milk teeth, 584
Mitral valve, 635
Mixed bones, 3
Modiolus of cochlea, 578
Molar glands, 583 ; teeth, 585 ; teeth, pecu-
liar, 585
Mons Veneris, 682
Monticulus cerebelli, 471
Morsus diaboli, 688
Motor oculi nerve, 477
Mouth, 582 ; mucous membrane of, 582 ;
muscles of, 197
Movement admitted in joints, 138
Mucilaginous glands, 134
Multicusj)idate teeth, 585
Multifidus spinse muscle, 227
Muscles, General Anatomy of, 185 ; arrange-
ment of fibres of, 185 ; bipenniform, 186 ;
derivation of names, 186; form of, 185;
fusiform, 186; involuntary, 185; mean-
ing of the terms origin, 186, insertion, ] 86 ;
INDEX.
737
Muscles {continued).
penniform, 186; radiated, 186; sheath
of, 185; size of, 186; structure of, 185;
voluntary, 185
Muscles or Muscle, Descriptive Anatomy :
of abdomen, 229 ; abductor minimi digiti
(hand) 266, (foot) 300, indicis, 268, pol-
iicis (hand), 264, (foot) 300 ; accelerator
urinee, 712 ; accessorii orbicularis oris,
197 ; accessorius pedis, 301 ; accessorius
ad sacro lumbalem, 225 ; of acromial re-
gion, 247 ; adductor brevis, 282, longus,
282, magnus, 282, pollicis (hand) 266,
(foot) 302 ; anconeus, 261 ; anomalus,
195; antitragicus, 569; of anus, 710,
715, of arm, 250 ; aryt^no-epiglottideus,
inferior, 647, superior, 647 ; arytge-
noideus, 646 ; attollens aurem, 190 ;
attrahens aurem, 190 ; azygos uvulas,
214
of back, 217; basio-glossus, 210; biceps
(arm) 251, (leg) 288 ; biventer cervicis,
226 ; brachial region, anterior, 254,
posterior, 260, 261 ; brachialis anticus,
252; buccinator, 198
caninus, 196; cerato-glossus,210; cervicalis
ascendens, 225 ; of chest, 242 ; chondro-
glossus, 210; ciliary of eye, 552; cir-
cumflexus palati, 214 ; coccygeus, 716 ;
cochlearis, 579; complexus, 226 ; com-
pressor narium minor, 195, nasi, 195,
sacculi laryugis, 647, urethree, 715 ;
constrictor, isthmi faucium, 210, pha-
ryngis inferior, 211, medius, 212, su-
perior, 212, urethrEe, 715; coraco-bra-
chialis, 251 ; corrugator supercilii, 191 ;
cremaster, 695 ; crico-arytsenoideus la-
teralis, 646^ posticus, 646 ; crico-thy-
roid, 646 ; crureeus, 280
deltoid, 247 ; depressor anguli oris, 197;
depressor ate nasi, 195, epiglottitis,
647, labii inferioris, 197; diaphragm,
238 ; digastric, 207 ; dilator naris, an-
terior, 195, posterior, 195 ; dorsum of
foot, 299
of external ear, 190; erector clitoridis,
713, penis, 713, spinse, 223; external
sphincter, 710; extensor brevis digi-
torum, 299, carpi radialis brevior, 259,
longior, 258, ulnaris, 260 ; coccygis,
228 ; digitorum communis, 260 ; in-
dicis, 262 ; longus digitorum, 291 ;
minimi digiti, 260 ; ossis metacarpi
pollicis, 261 ; primi internodii pollicis,
261; proprius pollicis, 291; secundi
internodii pollicis, 262 ; of eyelids,
191
of face, 189; femoral region, anterior,
276, internal, 281, posterior, 288 ; fibu-
lar region, 296 ; flexor accr ssorius, 301,
brevis minimi digiti (han^' ), 266, (foot),
302, digitorum, 300, polHc' s (hand), 265,
(foot), 302, carpi radialis, 255, ulnaris,
265, digitorum sublimis, 255, longus
digitorum, 295, pollicis (hand), 257,
(foot), 294, ossis metacarpi pollicis, 264,
profundus digitorum, 256 ; of foot, 297 ;
of fore-arm, 253
gastrocnemius, 292 ; gemellus superior,
287, inferior, 287 ; genio-hyo-glossus.
Muscles or Muscle {continued).
209; genio-hyoid, 208 ; of gluteal region,
. 283 ; gluteeus maximus, 283, medius,
284, minimus, 285 ; gracihs, 281
of liand, 263, 264 ; of head and face, 187 ;
helicis, major, 569, minor, 569; Hilton's,
647 ; of hip, 283 ; humeral region, an-
terior, 250, posterior, 252; of hyoid
boue and larynx, 205 ; hyo-glossus,
210
iliac region, 274 ; iliacus, 275, infra-costal,
237 ; infra-spinatus, 249 ; intercostal,
237 ; internal sphincter, 710 ; inter-
ossei of foot, 303, palmar, 268, dorsal,
267 ; interspinales, 228 ; iutertransver-
sales, 228
labial, 196 ; of larynx, 646 ; latissimus
dorsi, 230 ; laxator tympani, major,
575, minor, 575 ; of leg, 289 ; levator
anguli oris, 196, scapulae, 221, ani,
715, glandulse thyroidaj, 658 ; labii in-
ferioris, 196, superioris alaeque nasi,
195, proprius, 196, proprius alee nasi,
posterior, 195, anterior, 195, menti, 196,
palati, 213, palpebraj, 192, prostatsg,
716 ; levatores costarum, 238 ; lingualis,
210 ; of lips, 196 ; longissimus dorsi,
225 ; longus colli, 216 ; lumbricales
(hand), 267, (foot), 301
masseter, 198; of mouth, 197; multifidus
spinee, 227 ; musculus accessorius ad
sacro-lumbalem, 225 ; mylo-hyoid, 208 ;
myrtiformis, 195
naso-labialis, 197 ; of neck, 201 ; of nose,
195
obliquus auris, 570, abdominis externus,
23u, internus, 231 ; capitis, superior,
228, inferior, 228 ; oculi, inferior, 194,
superior, 193 ; obturator, externus, l-§8 ;
287, internus, 286 ; occipito-frontalis,
omo- hyoid, 207; opponens minimi
digiti, 267, pollicis, 264 ; orbicularis
oris, 197, palpebrarum, 191 ; of orbit,
192
palate, 213 ; palato-glossus, 210, 214; pa-
lato-pharyngeus, 214 ; palmaris brevis,
266, longus, 255 ; pectineus, 282 ; pecto-
ralis major, 242, minor, 244 ; of penis
712 ; of perinseum, male, 712, female,
714; peroneus brevis, 220, longus, 296,
tertius, 291 ; of pericranium, 188 ; of
pharynx, 211 ; of the pinna, 569 ; plan-
taris, 293 ; platysma myoides, 202 ;
popliteus, 294 ; pronator quadratus,
257, radii teres, 254 ; psoas magnus,
275, parvus, 275 ; pterygoid, internal,
^ : 2^", external, 201 ; pyramidalis abdo-
minis, 235, nasi, 195 ; pyriformis,
286
quadratus femoris, 287, lumborum, 235,
menti, 197 ; quadriceps extensor cruris,
279
radial region, 258 ; rectus abdominis,
234, capitis anticus major, 215, minor,
215 ; posticus major, 228, minor, 228,
femoris, 279, oculi, externus, superior,
inferior, and internal, 193, lateralis,
215; retrahens aurem, 190; rhom-
boideus major, 221, minor 221 ; riso-
rius, 198 ; rotatores spinae, 227
3^
738
INDEX.
Muscles or Muscle {continued).
sacro - lumbalis, 225 ; sartorius, 278 ; sca-
lenus anticus, 217, medius, 217, posticus,
217 ; scapular region, anterior, 247,
posterioi", 248 ; semi-membranosus, 289 ;
serratus posticus, superior, 222, inferior,
222 ; semi-spinalis dorsi, 227, colli, 227 ;
semitendinosus, 288 ; serratus magnus,
246 ; sole of foot, 299, first layer, 299,
second layer, 301, third layer, 302 ;
soleus, 223 ; sphincter, external, 710,
internal, 710, vaginse, 714 ; spinalis
dorsi, 226, cervicis, 226 ; splenius, 223,
caiHtis, 223, colli, 223 ; stapedius, 575 ;
sterno-cleido - mastoid, 204 ; sterno-
hyoid, 205 ; sterno-thyroid, 206 ; stylo-
glossus, 210; stylo- hyoid, 208; stylo-
pharyngeus, 212 ; subanconeus, 253 ;
subclavius, 245 ; subcrurgeus, 280 ; sub-
scapularis, 248 ; supinator brevis, 26 1
longus, 258 ; supra-spinales, 227, supra-
spinatus, 248
temporal, 200 ; tensor palati, 214 ; tarsi,
192; tympani, 575; vaginse femoris, 278;
teres major, 250, minor, 249; thoracic
region, anterior, 242, lateral 246; of tho-
rax, 236; of thigh, 276; thyro-aryt«-
noideus, 646 ; thyro-epiglottideus, 647 ;
thyro-hyoid, 206 ; tibialis anticus, 290,
posticus, 295 ; tibio-fibular region, an-
terior, 290 ; of tongue, 209 ; trachelo-
mastoid, 225; tragicus, 569 ; transversa-
lis abdominis, 233, colli, 225 ; trausversus
auriculae, 569, pedis, 302, periusei, 713,
(female) 714; trapezius, 218; triangu-
laris sterni, 227 ; triceps, extensor cu-
biti, 252, extensor cruris, 279 ; of trunk,
217 ; of tympanum, 575
upper extremity, surgical anatomy of,
268; of ureters, 667 ; of urethra, 712
vastus externus, 279, internus and
crurseus, 280; vertebral region, ante-
rior, 215, lateral, 217
zygomaticus major, 196, minor, 196
Musculi jiapillares, left ventricle, 635, right,
633 ; pectinati in left auricle, 635, in
right, 632
Musculo-cutaneous nerve of arm, 509, from
peroneal, 530
Musculo-spiral nerve, 514
Musculo-phrenic artery, 347
Musculus accessorius ad sacro-lumbalem,
215
Mylo-hyoid groove, 52 ; muscle, 208 ; nerve,
493 ; ridge, 51
Myrtiform fossa, 40
Myrtiformis muscle, 195
Nails, chemical composition of, 545 ; lunula
of, 545 ; matrix of, 545 ; root of, 545 ;
structure of, 545
Nares, anterior, 63, posterior, 60 ; septum
of, 66
Nasal angle, 40; artery, 329, 336 ; bones,
39, articulations o^ 40; cartilages, 551;
crest, 40 ; duct, 567 ; eminences, 27 ;
fossae, Q5^ 552, arteries of, 553, mucous
membrane of, 552, nerves of, 553, veins
of" 553; groove, 40; nerve, 486; nerves
Nasal {continued)
from Meckel's ganglion, 490; notch,
25 ; process, 43 ; spine, 26, anterior, 44,
posterior, 47 ; venous arch, 403
Naso-maxillary suture, 63
Naso-palatine canal, 50; nerve, 490
Nates of brain, 469
Neck, muscles of, 201 ; triangle of, anterior,
330, posterior, 331, surgical anatomy of,
330 ; veins of, 402. 404
Nerves, General Anatomy of, 440 ; afferent
or centripetal, 440; cerebro-spinal, 440,
composition of, 440, junction of funiculi,
441, neurilemma of, 440, origin of, 441,
apparent, 442, real, 442, plexus of, 441,
sheath of, 440, structure, 440, 441, sub-
divisions of, 441, termination of, 442,
vessels of, 441; compound, 475; efferent
or centrifugal, 440 ; of motion, 475, 477 ;
reflex or excito-motory, 440 ; spinal, roots
of, 501 ; of special sense, 475
Nerves or Nerve, Descriptive Anatomy of:
abducens, 479 ; accessory obturator, 522,
spinal, 496 ; acromiales, 504 ; anterior
crural, 522; of arachnoid, 449; arti-
cular of elbow, 513, hip, 522, 528,
knee, 522, 524, 528, 530, shoulder joint,
508, 509, wrist, 516 ; auditory, 477, 581 ;
auricular, posterior, 481, of vagus, 498 ;
of auricularis magnus, 504; of auriculo-
temporal, 492, of second cervical, 506 ;
of small occipital, 504 ; axillary, 506
of hope, 3 ; buccal, 491, of facial, 483
cardiac, 536, middle, 536, inferior, 536,
superior, 536, of pneumogastric, 499 ;
cavernous of penis, 541 ; cervical an-
teiior, 502, posterior, 505, superficial,
503; cervico-facial,483; chorda tympani,
481, 576 ; ciliary, long, 487, short, 487 ;
circumflex, 509 ; claviculares, 504 ;
coccygeal, 524, anterior branch, 525, pos-
terior, 524; cochlear, 518; communicans
noni, 505, peronei, 530 ; of Cotuunius,
490 ; cranial, 475 ; crural anterior, 522 ;
cutaneous, abdominal anterior, 617, late-
ral, 517, of arm, external, 509, small in-
ternal, 510, cervical, 506, of circumflex,
509, coccygeal, 525, dorsal, 516, of lesser
sciatic, 528, lumbar, 518, of musculo-
spiral, 515, of obturator, 522, palmar,
511, patellse, 523, peroneal, 530, plantar,
529, radial, 515, sacral, 524, of thigh,
external, 520, middle, 522, internal, 523,
thoracic anterior, 517, lateral, 517 ;
ulnar, 513
deep temporal, 491 ; dental anterior, 489,
inferior, 493, posterior, 489 ; descendens
noni, 484 ; digastric from facial, 481 ;
digital (foot), dorsal, 530, 531, plantar,
629, 530, (hand), dorsal, 513, 515, palmar,
median, 511, ulnar, 514, radial, 515 ;
dorsal of penis, 526 ; dorsi lumbar,
518, of dura mater, 448
eighth pair, 494 ; of eyeball, 564
facial, 480 ; of femoral artery, 522 ; fifth,
485 ; fourth, 478 ; frontal 486
ganglionic branch of nasal, 486 ; gastric
branches of vagus, 500; genito-crural,
620 ; glosso-pharyngeal, 494 ; gluteal,
inferior, 526, superior, 525 ; great petro-
INDEX.
739
Nerves or Nerve {continued).
sal, 491, great splanchnic, 537 ; gus-
tatory, 492
liEemorrlioida], inferior, 526 ; plexus su-
perior, 539, inferior, 540, of heart, 536,
637, hepatic, 539, 617 ; hypo-glossal,
ilio -hypogastric, 519; ilio-inguinal, 520;
incisor, 493 ; inferior cardiac, 536 ; in-
ferior maxillary, 491 ; infra-maxillar}',
483, of facial, 482 ; infra-trochlear, 487 ;
inter-costal, lower, 517, upper, 516 ; in-
tercosto - humeral, 517; interosseous,
anterior, 511, posterior, 515, of intes-
tines, 539 ; ischiadic, great, 528, small,
526
Jacobson's, 576
of labyrinth, 581, labial, 489 ; lachrymal,
486 ; of Lancisi, 462 ; large cavernous,
541 ; laryngeal, external, 498, internal,
499, recurrent, 499, superior, 498 ; lesser
splanchnic, 538 ; lingual, 483, of fifth,
492, of glosso-pharyngeal, 496 ; long
ciliary, 487; lumbar, 518; lumbo-sacral,
518
malar branch of orbital nerve, 489, of
facial, 482 ; masseteric, 491 ; maxiUary,
inferior, 491, superior, 487 ; median,%ll ;
mental, 493 ; middle cardiac, 536 ; mo-
tor of eye, common, 477, external, 479 ;
musculo-cutaneous of arm, 509; of leg,
530; musculo-spiral, 514; mylo-hyoid,
493
nasal, of ophthalmic, 486, from Meckel's
ganglion, 490, from Vidian, 491 ; naso-
palatine, 490 ; ninth, 483
obturator, 520; oesophageal, 499 ; occipital,
great, 506, small, 504, of third cervical,
506, of facial, 481 ; olfactory, 475; oph-
thalmic, 485 ; optic, 476 ; orbital nerves,
their relation, 479, in cavernous sinus,
479, in orbit, 479, in sphenoidal fissure,
479 ; orbital, 4b 8
palatine, anterior or large, 490, external
490, posterior or small, 490; palmar-
cutaneous, 511, of median, 511, ulnai-,
513 ; palpebral, 489 ; pathetic, 478 ;
perforans Gasserii, 509 ; perineal, 526,
superficial, 526 ; peroneal, 530 ; pe-
trosal, superficial external or large 481,
491, small, 493 ; pharyngeal of pneu-
mogastric, 498, of glosso-phavyngeal,
496, of sympathetic, 535, of Meckel's
ganglion, 491, from external laryngeal,
499 : phrenic, 505 ; plantar, cutaneous,
529, external, 529, internal, 529 ; pneu-
mogastric, 497 ; po]Dliteal, external, 530,
internal, 528 ; portio dura, 480, portio
inter duram et moUem, 480 ; portio
mollis, 477; posterior auricular, 481;
pterygoid, 492; pterygo-palatine, 491 ;
pudendal, inferior, 528 ; pudic, 526 ;
pulmonary from vagus, 499
radial, 515; recurrent laryngeal, 499;
renal splanchnic, 538 ; respiratory ex-
ternal, 508
sacral, 524 ; saphenous long or internal
523, short or external, 528; sciatic,
great, 528, small, 526 ; short ciliary,
487 ; sixth, 479 ; small cavernous, 541 ;
Nerves or Nerve {continued),
spermatic, 539 ; spheno-palatine, 489 ;
spinal, 501, accessory, 496 ; splanclmic,
great, 537, small, 538, smallest, 538 ;
splenic, 539; sternalcs, 504; stylo-hyoid
of facial, 481 ; subclavian, 507 ; subocci-
pital, 502, posterior branch of, 506 ;
subscapular, 508 ; superficialis colli,
503 ; superior cardiac, 536, maxillary,
487 ; supra-clavicular, 504 ; supra-orbi-
tal, 486 ; supra-scapular, 508 ; supra-
trochlear, 486 ; sympathetic, 440, 532
temporal deep, 491, of facial, 492, of auri-
culo-temporal, 492, of orbital nerve, 488 ;
temporo-facial, 482 ; temporo-malar or
orbital, 489 ; third, or motor oculi, 477 ;
thoracic posterior, 508 ; anterior, 508 ;
thyro-hyoid, 484 ; tibial, anterior, 530,
posterior, 529; of tongue, 550 ; tonsillar,
496, trifacial, 485 ; tympanic, of glosso-
pharyngeal, 496, 576 ; of facial, 481
ulnar, 513 ; uterine, 541
vaginal, 541 ; vagus, 497 ; vestibular, 581 ;
Vidian, 491
of Wrisberg, 510
Nervous substance, chemical analysis, 439
Nervous System, General Anatomy of, 439 ;
cerebro-spinal axis, 439 ; ganglia, 440 ;
grey or cortical substance, 439 ; nerves,
440 ; subdivision of, 439 ; sympathetic,
442, composition of, 442, gelatinous fibres
of, 442, structure of, 442, tubular fibres of,
442 ; white or medullary substance, 439
Nervi nervorum, 441
Nervus cardiacus magnus, 536, minor, 536 ;
superficialis cordis, 536
Neurilemma, 440, of cord, 444
Ninth nerve, 483
Nipple, 690
Nodule of cerebellum, 471
Noduli Arantii, 633
Nose, 550 ; arteries of, 552 ; bones of, 39 ;
cartilages of, 550 ; cartilage of septum of,
551 ; fossse of, 65 ; mucous membrane of,
552 ; muscles of, 195, 551 ; nerves of, 552 ;
veins of, 403, 552
Notch, cotyloid, 81 ; ethmoidal, 26 ; inter-
condyloid, 114; nasal, 25; pterygoid, 36 ;
sacro-sciatic, greater, 79, 83, lesser, 80, 83 ;
sigmoid, 53 ; spheno-palatine, 49 ; supra-
orbital, 25 ; supra-scapular, 89
Nuck, canal of, 681, 690
Nummular layer of retina, 561
Nymphee 683 ; lymphatics of, 435
Oblique inguinal hernia, 698, course of, 698,
coverings of, 698 : ligament, 163 ; line of
the clavicle, 85, lower jaw, 51, of radius,
101
Obliquus auris muscle, 570 ; externus abdo-
minis, 230, internus, 231 ; inferior cervi-
cis, 228, superior, 228 ; inferior oculi, 194,
superior, 193
Obturator artery, 378, peculiarities of, 379,
relation of to femoral ring, 706 ; externus
muscle, 287, internus, 286 ; fascia, 720 ;
foramen, 81 ; ligament or membrane, 156 ;
nerve, 520, accessory, 522 ; veins, 419
Occipital artery, 324 ; bone, 19, articulations
3 B 2
740
INDEX.
Occipital (continued).
of, 22, attachment of muscles to, 22, de-
velopment, 22, structure of, 22 ; crests,
20, protuberances, 20 ; fossse inferior, 58 ;
groove, 29; lymphatic glands, 428; sinus,
428 ; triangle, 331 ; vein, 404
Occipitalis, major nerve, 506, minor, 504
Occipito-atloid articulation, 143 ; occipito-
axoid articulation, 144 ; occipito-frontalis,
muscle, 188
Occiput, arteries of, 324
■Odontoid ligament, 144, tubercle for, 20 ;
process of axis, 7
CEsophageal arteries, 364 ; branches of vagus
nerve, 499 ; glands, 597
CEsophagus, 595, lymphatics of, 438, struc-
ture of, 596, surgical anatomy of, 596 ; re-
lations of, in neck, 596, m thorax, 596
Oesterlen, on supra-renal capsules, 664
Olecranon process, 97 ; fracture of, 271
Olfactory bulb, 476 ; foramina, 37 ; nerve,
475, peculiarities of, 476
Olivary bodies of medulla oblongata, 452, 453 ;
process, 32, 57
Omenta, 601
Omentum, gastro-colic, 601 ; gastro-hepatic,
601 ; gastro-splenic, 601, great, 600, 601,
lesser, 599, 601 ; sac of, 600
Omo-hyoid muscle, 207
Opening, of aorta in left ventricle, 635 ;
aortic in diaphragm, 240 ; caval in dia-
phragm, 240; ofcoronary sinus, 631 ; of in-
ferior cava, 631 ; left auriculo-ventricular,
634, 635 ; oesophageal in diaphragm, 240 ;
of pulmonary artery, 632, veins, 634 ; right
auriculo-ventricular, 63 1 ; saphenous, 278,
703 ; of superior cava, 631
Operation for club foot, 297 ; of laryn-
gotomy, 651; of laryngo - tracheotomy,
652; of lithotomy, 717 ; of oesophagoto-
my, 590 ; of staphyloraphy, 215 ; for stra-
bismus, 194 ; tracheotomy, 652
ligature of the anterior tibial, 393, over
instep, 393, in lower third of leg,
393, in upper part of leg, 393 ; axillary
artery, 351
brachial artery, 354, 355
common carotid artery, 318, above omo-
hyoid, 318, below omo-hyoid, 318 ; com-
naon iliac artery, 374
dorsalis pedis artery, 394
external carotid, 319, iliac artery, 381
femoral artery, 386
innominate artery, 314 ; internal iliac ar-
tery, 375
lingual artery,
popliteal artery, 390, in upper part of its
course, 390, in lower part, 390; pos-
terior tibial, 396, in middle of leg,
396, at lower third of leg, 396, at ankle,
396
radial artery, 358
subclavian artery, 341 ; superior thyroid
artery, 320
ulnar artery, 361
Opereula of dental grooves, 589
Ophthalmic artery, 334; ganglion, 487 ; nerve,
485 ; vein, 409
Opponens minimi digiti muscle, 267 ; pollicis
muscle, 264
Optic" commissure, 476 ; foramen, 32, 35 ;
groove, 32, 57 ; lobes, 462 ; nerve, 476,
477 ; thalami, or lobes, 467 ; tract, 476
Ora serrata, 560
Orbicular bone, 574 ; ligament, 163
Orbicularis oris muscle, 197 ; palpebrarum,
191
Orbit, 64 ; arteries of, 334 ; muscles of, 192 ;
relation of nerves in, 479
Orbital artery, 329 ; nerve, 488 ; process of
malar, 45, of palate, 48
Organs of circulation, 628 ; of deglutition,
594; of digestion, 582; of generation, fe-
male, 682, male, 671; of respiration, 641 ; of
sense, 542; urinary, 660; of voice, 641
Organic constituent of bone, 1
Orifice, oesophageal of stomach, 602 ; of pro-
static ducts, 669 ; pyloric of stomach, 602;
of uterus, 668 ; of vagina, 683
Os calcis, 122; hyoides, 67; innominatum,
76 ; orbiculare, 574 ; planum, 38
Os uteri, 686
Ossa triquetra, 39
Ossicula, 574.; ligaments of, 574
Ossification of bone, 4 ; of spine, progress
in, 12
Osteo-dentine, 588
OsteMogy, 1
Ostium abdominale of Fallopian tube, 685,
uterinum, 688 ; uteri internum, 686
Otic ganglion, 493
Otoliths, 581
Outlet 'Of pelvis, S3
Ovarian arteries, 373 : plexus of nerves, 532 ;
veins, 421
Ovary, 688 ; corpus luteum of, 689 ; Graafian
vesicles of, 689 ; ligament of, 690 ; lym-
phatics of, 436 ; nerves of, 690 ; ovisacs
of, 689; shape, position, and dimensions,
689 ; situation in foetus, 690 ; stroma of,
689 ; tunica albuginea of, 689 ; vessels of,
690
Ovicapsule of Graafian vesicle, 689
Oviducts, 688
Ovisacs of ovary, 689
Ovula of Naboth, 687
Ovum, 689
Pacchionian depressions, 55
Palatal glands, 591
Palate, arches of, 592, hard, 591, soft, 591;
bone, 46, articulation of, 49, attach-
ment of muscles to, 49, development of,
49, turbinated crests of, 47, vertical plate
of, 47 ; horizontal plate of, 46 ; muscles
of, 213; orbital process of, 48; process,
43 ; sphenoidal process of, 48
Palatine artery, ascending, 322, descending,
329, posterior, 329 ; canal, anterior, 43,
58, accessory, 47 ; fossa, anterior, 43, 58 ;
nerves, 489; process of superior maxillary,
41 ; veins, inferior, 403
Palato-glossus muscle, 210, 214 ; pharyngeus
214
Palmar arch, deep, 358, superficial, 361 ; cu-
taneous nerve, 511 ; fascia, 246 ; interossei
arteries, 360; nerve, deep of ulnar, 514,
superficial, 514
Palmaris brevis muscle, 266 ; longus muscle,
255
INDEX.
741
Palpebrae, 564
Palpebral arteries, 336 ; cartilages, 564 ; fis-
sure, 564 ; folds of conjunctiva, 566 ; liga-
ment, 564 ; muscles, 191 ; veins, inferior,
403, superior, 403
Pampiniform plexus of veins, 420
Pancreas, 621 ; structure of, 622 ; vessels
and nerves of, 622
Pancreatic arteries, 370 ; duct, 622; plexus
of nerves, 539 ; veins, 422
Pancreatica magna artery, 370
Pancreatico-duodenal artery, 369, inferior,
370; vein, 422 ; plexus of nerves, 539
Papilla lachrymalis, 567
Papillae of tooth, 588 ; conicse et filiformes,
550 ; conjunctival, 566 ; fungiformes
(mediae), 549 ; of kidney, 661 ; maximae
(circumvallate), 548 ; of skin, 543 ; of
tongue, 548
Papillary stage of development of teeth,
588
Par vagum, 497
Parietal bones, 22, articulations of, 24,
attachment of muscles to, 24, develop-
ment of, 24; eminence, 22; foramen,
23
Parotid duct, 593 ; gland, 592, accessory
portion of, 593, nerves of, 594, vessels of,
594 ; lymphatic glands, 428 ; veins, 403
Patella, 116, articulations of, 116, attach-
ment of muscles to, 116, devel&pment of
116; fracture of, 305
Pectineus muscle, 282
Pectiniform septum, 673
Pectoral region, dissection of, 242
Pectoralis major, 242, minor, 244
Peculiar dorsal vertebrae, 9
Peculiarities of clavicle, 86 ; of sacrum, 15 ;
of arteries. 8ee each Artery.
Pedicles of a vertebra, 5
Peduncles of cerebellum, 474 ; of cerebrum,
460 ; of corpus callosum, 458 ; of pineal
gland, 468
Pelvic fascia, 719, parietal or obturator
layer, 720 ; visceral layer, 720 ; plexus,
540
Pelvis, 76, 82 ; arteries of, 375 ; articulation
of, 152; axes of, 84; boundaries of, 664 ;
brim of, 83 ; cavity of, 83 ; diameters of,
83 ; false, 82 ; inlet of, 83 ; ligaments of,
152 ; lymphatics of, 435 ; male and female,
differences of, 84 ; outlet of, 83 ; position
of, 83 ; position of viscera at outlet of,
716 ; true, 83; of kidney, 662
Penis, 672 ; arteries of, 674 ; body of, 672 ;
corpora cavernosa, 673 ; corpus spongio-
sum, 673 ; dorsal artery of, 380, nerve of,
526 ; ligament suspensory, 672 ; lympha-
tics of, 435, 674 ; muscles of, 712 ; nerves
of, 674 ; prepuce of, 672 ; root of, 672
Penniform muscles, 186
Perforans Gasserii nerve, 509
Perforated space, anterior, 459, posterior,
460
perforating arteries, of hand, 360; from mam-
mary artery, 347 ; from plantar, 398; from
profunda, 388, inferior, 389, middle, 389,
suxjerior, 388
Pericardiac arteries, 347, 364
Pericardium, relations of, 628; structuref.
I Pericardium {continued).
629 ; fibrous layer of, 629 ; serous layer
of, 629; vessels of, 629
Perilymph, 579
Perinaeal artery, superficial, 380, transverse,
380; fascia, deep, 715, suj^erficial, 526;
nerve, 526
Perinaeum, abnormal course of arteries in,
719; deep boundaries of, 711 ; lymphatics
of, 435; muscles of, 712; surgical anatomy
of, 709, 711
Periosteum, 3
Peritoneum, lesser cavity of, 600 ; ligaments
of, 601; mesenteries of, 601; omenta of,
601 ; reflections traced, 599
Permanent teeth, 584
Peroneal artery, 396, anterior, 397, peculiari-
ties of, 397 ; nerve, 530 ; veins, 418
Peroneus brevis muscle, 296 ; longus, 296 ;
tertius, 291
Perpendicular plate of ethmoid, 37
Pes accessorius, 465 ; hippocampi, 465
Petit, canal of, 563
Petro-occipital suture, 54
Petro-sphenoidal suture, 54
Petrosal nerve, superficial large, from Vidian,
491, external, 481, small, 493; sinus-, in-
ferior, 409, superior, 409
Petrous ganglion, 496 ; portion of temporal
bone, 29
Peyer's glands, 608
Phalanges (hand), 108, articulations of, 170,
development of, 110 ; (foot), 130, articula-
tions of, 184, development of, 131
Pharyngeal aponeuroois, 595 ; artery ascend-
ing, 325 ; ganglion, 535 ; glands, 595 ;
nerve, from external laryngeal, 499, from
glosso-pharyngeal,496, from Meckel's gang-
lion, 491, from sympathetic, 535, from
vagus, 498 ; plexus of nerves, 498, 535 ;
spine, 20 ; veins, 405
Pharynx, 594 ; aponeurosis o:^ 595 ; arteries
of, 325 ; mucous membrane of, 595 ;
muscles of, 211 ; structure of, 595
Phlebolites, 419
Phrenic arteries, 374 ; nerve, 505 ; plexus
of nerves, 538 ; veins, 421
Pia- mater of brain, 450 ; vessels and nerves
of, 450 ; of cord, 444, structure of, 444 ;
testis, 677
Pigmentary layer of choroid, 557
Pillars of external abdominal ring, 694 ; of
diaphragm, 239 ; of fauces, 592 ; of fornix,
466
Pineal gland, 468 ; peduncles of, 468
Pinna of ear, 567 ; ligaments of, 568 ; mus-
cles of, 569 ; nerves of, 570 ; structure of
568 ; vessels of, 570
Pisiform bone, 105
Pituitary body, 459; fossa, 32, 57; mem-
brane, 552
Plantar artery, external, 397, internal, 397 ;
fascia, 298 ; cutaneous nerve, 529 ; nerve,
external, 529, internal, 529 ; veins, exter-
nal, 418, internal, 418
Plantaris muscle, 293
Platysma myoides, 202
Pleura, cavity of, 653 ; costalis, 653 ; pul-
monalis,.652 ; reflections of traced, 653 ;
vessels and nerves of, 653
742
INDEX.
Pleurse, 652
Plexus op Nerves, aortic, 539 ; brachial,
506 ; cardiac, deep, 536, superficial,
537; carotid, 534, external, 535, ca-
vernous, 534 ; cerebral, 535; cervical, 503,
posterior, 506; coeliac, 539; colic, left,
539, middle, 539, right, 539 ; coronary
ant rior, 537, posterior, 537 ; cystic, 539 ;
diaphragmatic, 538 ; epigastric or solar,
538; facial, 535; gastric, 539; gastro-duo-
denal, 539; gastro-epiploic, 539, left, 539 ;
great cardiac, 536 ; hsemorrhoidal, supe-
rior, 539, inferior, 540 ; hepatic, 539 ; hy-
pogastric, 540, inferior, 540 ; ileo-colic, 639 ;
infra-orbital, 489 ; lumbar, 518 ; magnus
profundus, 536 ; meningeal, 535 ; mesen-
teric, inferior, 539, superior, 539 ; oesopha-
geal, 500 ; ovarian, 539 ; ophthalmic, 535 ;
pancreatic, 539 ; pancreatico - duodenal,
539 ; patellar, 523 ; pharyngeal, 498, 535 ;
phrenic, 538 ; prostatic, 541 ; pulmonaiy
anterior, 499, posterior, 499 ; pyloric, 539 ;
renal, 538; sacral, 525; sigmoid, 539;
solar, 538 ; spermatic, 539 ; splenic, 539 ;
superficial cardiac, 536 ; supra-renal, 538 ;
tonsillar, 496 ; tympanic, 496, 576 ; vaginal,
541 ; vertebral, 536 ; vesical, 540
Plexus op Veins, choroid, 464 ; hsemor-
rhoidal, 419; pampiniform, 420; pros-
tatic, 419 ; pterygoid, 403 ; ovarian, 421 ;
spermatic, 420 ; uterine, 419; vaginal, 419;
vesico-prostatic, 419
Plica semilunaris, 566
Pneumogastric nerve, 497
Points of ossification, 4
Pomum Adami, 641
Pons hepatis, 615 ; Tarini, 460
Pons Varolii, 454 ; longitudinal fibres of,
455 ; septum of, 455 ; structure of, 454 ;
transvei'se fibres of, 454
Popliteal artery, 390, branches of, 391, pecu-
liarities of, 390 ; surgical anatomy of, 390 ;
lymphatic glands, 433 ; nerve, external,
530, internal, 529 ; space, 389 ; vein,
318
Popliteus muscle, 294
Pores of the skin, 547
Portal canals, 618 ; fissure, 615: vein, 400,
423, 617, 618
Portio dura of seventh nerve, 480 ; mollis,
477 ; inter duram et mollem, 480
Porus opticus of sclerotic, 555
Position of pelvis, 83
Posterior annular ligament, 263 ; aperture
of nares, 60 ; dental canals, 40 ; ethmoidal
cells, 38 ; fontanelle, 21 ; fossa of skull,
57 ; nasal spine, 47 ; palatine canal, 41 ;
triangle of neck, 331
Pott's fracture, 306
Pouches laryngeal, 646
Poupart's ligament, 230, 694, 703
Prepuce, 672
Preputium clitoridis, 683
Princeps cervicis artery, 324 ; poUicis artery,
360
Processes or Process, acromian, 89 ; alveo-
lar, 43 ; angular, external, 25, internal,
25, auditory, 30
basilar, 20
clinoid, anterior, 32, 57, middle, 32, j)os-
Processes or Process {continued).
terior, 33, 57 ; cochleariform, 573 ; con-
dyloid of lower jaw, 53; coracoid, 90;
coronoid of lower jaw, 53 ; of ulna, 97
ethmoidal of inferior turbinated, 49
frontal of malar, 45
hamular, 35; of helix, 568
of Ingrassias, 35
jugular, 20
lachrymal of inferior turbinated bone,
49
malar, 43 ; mastoid, 29 ; maxillary, 47, of
inferior turbinated, 49, of malar bone,
46 ; mental, 51
nasal, 43
odontoid of axis, 7 ; olecranon, 97 ; olivary,
32, 57 ; orbital of frontal, 26 ; of malar,
45, of palate, 48, of superior maxillary,
41
palate, 43 ; palatine of superior maxillary,
41 ; pterygoid of palate bone, 47, of
sphenoid, 35
sphenoidal of palate, 48 ; spinous of tibia,
117, of ilium, 79, of sphenoid, 34; sty-
loid of temporal, 30 ; of ulna, 100 ; of
radius, 101 ; superior vermiform of
cerebellum, 470
unciform, 107, of ethmoid, 38
vaginal, 30
zygomatic, 27
Processes ciliary, 558
Processus ad meduUam, 474 ; ad pontem,
474;^brevis of malleus, 574; cochleari-
foi-mis, 31, 573 ; e cerebello ad testes,
474 ; gracilis of malleus, 674
Profunda cervicis artery, 347 ; femoris
artery, 387, vein, 418; inferior artery,
356, superior, 355
Progress of ossification in the spine, 12
Promontory of tympanum, 572 ; of sacrum,
12
Pronator quadratus muscle, 257 ; radii teres
muscle, 254
Prostate gland, lobes of, 671 ; levator muscle
of, 716 ; position of, 671 ; size and shape,
671 ; structure of, 671 ; surgical anatomy
of, 716 ; vessels and nerves of, 672
Prostatic plexus of nerves, 541 ; of veins ;
419 ; portion of urethra, 668 ; fluid, 672,
sinus, 669
Protuberance, occipital, external, 20, inter-
nal, 20
Psoas magnus muscle, 275, parvus, 275
Pterygo -maxillary fissure, 62, ligament,
198
Pterygo-palatine artery, 329, canal, 34, nerve,
491
Pterygoid arteries, 328 ; muscles, external,
201, internal, 200 ; fossa of sphenoid, 35,
of lower jaw, 53 ; nerves, 492 ; notch, 36 ;
plexus of veins, 403 ; process of palate
Ijone, 47 ; processes of sphenoid, 35 ; ridge,
34
Pubes, 80 ; angle of, 80; ci'est of, 83 ; spine
of, 80 ; symphysis of, 80
Pubic arch, 83 ; articulations of, 155
Pubo-prostatic ligaments, 666
Pudendum, 682
Pudic artery, in male, 379, peculiarities of,
379, in female, 380, deep external, 387,
INDEX.
743
Pudic {continued).
superficial, 692, superficial external, 387 ;
nerve, 526; vein, external, 417, internal,
419
Pulmonary artery, 399, 657, opening of in
right ventricle, 632; capillaries, 657;
nerves from vagus, 499 ; veins, 400, 424,
657, openings of in left auricle, 634
Puncta vasculosa, 461 ; lachrymalia, 564,
567
Pulp cavity of tooth, 587 ; of teeth, develop-
ment of, 589
Pupil of eye, 558 ; membrane of, 559
Pyloric artery, 368, inferior, 369 ; plexus,
539
Pylorus, 604
Pyramid in vestibule, 577 ; of cerebellum,
471 ; of thyroid gland, 658
Pyramidalis muscle, 235 ; nasi, 195
Pyramids, anterior, 573, decussation of,
451, posterior, 452; of Ferrein, 662; of
Malpighi, 661 ; of the spine, 17
Pyriformis muscle, 286
Quadriceps extensor cruris muscle, 279
Quadratus femoris muscle, 287 ; lumborum,
235
Quadrigeminal bodies, 469
Radial artery, 357 ; branches of, 358 ; pecu-
liarities of, 358 ; relations of in fore-arm,
357, in the hand, 358, at the wrist, 357 ;
surgical anatomy of, 358 ; lymphatic
glands, 430 ; nerve, 515 ; recurrent artery,
358; region, muscles of, 258; vein, 411
Eadialis indicis artery, 360
Radiating fibres of retina, 561
Eadio-ulcar articulations, inferior, 164, mid-
dle, 163, superior, 163
Radius, 100, articulations of, 102, develop-
ment of, 102, fracture of, 271, of lower
end, 272, of neck, 271, of shaft, 272;
grooves in lower end of, 102; muscles
attached to, 102 ; oblique line of, 101 ;
sigmoid cavity of, 101 ; tuberosity of, 101 ;
and ulna, fracture of, 272
Rami of the lower jaw, 50 ; of pubes, 80
Ramus of ischiimi, 80
Ranine artery, 321 ; vein, 403
Raphe of corpus callosum, 462 ; of palate,
591 ; of perinaeum, 711 ; of tongue, 547
Receptaculum chyli, 427
Recto-uterine ligaments, 686
Recto-vesical fascia, 720 ; fold, peritoneal,
600
Rectum, relations of, male, 611, female, 685 ;
columns of, 613 ; lymphatics of, 435 ;
sugical anatomy of, 716
Rectus abdominis, 234 ; capitis anticus
major, 215, minor, 215; posticus major,
228, minor, 228 ; lateralis, 215; femoris
muscle, 279 ; oculi, internus, superior,
inferior, and external, 193
Recurrent artery, radial, 358, tibial, 393 ;
ulnar, anterior, 361, posterior, 361 ; nerves
to tentorium, 478
Region, of abdomen, 229, 597; acromial,
muscles of, 247, auricular, 190
Region {continued).
back, muscles of, 218, brachial, anterior,
254, posterior^ 260
cervical, superficial muscles of, 202
diaphragmatic, 238
epicranial, muscles of, 188 ; epigastric, 598
femoral, muscles of, anterior, 276, internal,
281, posterior, 288, fibular, 296 ; foot,
dorsum of, 299, sole of, 299
gluteal, muscles of, 283 ; groin, 700
of hand, muscles of, 264^ humeral, ante-
rior, 250, posterior, 252 ; hypochondriac,
598 ; hypogastric, 598
iliac, muscles of, 274, infra-hyoid, 205;
inguinal, 598, 692; inter-maxillary,
muscles of, 197 ; ischio-rectal, 709
laryngo-tracheal, surgical anatomy of, 650 ;
lingual, muscles of, 209 ; lumbar, 598
maxillary, muscles of, inferior, 196, supe-
rior, 196
nasal, muscles of, 192
orbital, muscles of, 192
palatal, muscles of, 213, palpebral, 191 ;
perinasum, 709, 711 ; pharyngeal mus-
cles of, 211 ; popliteal, 389; pterygo-
maxillary, muscles of, 200
radial, muscles of, 258
scapular, muscles of, anterior, 247, poste-
rior, 248 ; Scarpa's triangle, 384 ; supra-
hyoid, muscles of, 207
temporo-maxillary, muscles of, 198, tho-
racic, 236, anterior, 242, lateral, 246,
tibio-fibular, anterior, 290, posterior,
292
umbilical, 598
vertebral, muscles of, anterior, 215, lateral,
217
Renal artery, 373, 662 ; plexus, 538 ; veins,
421
Reservoir of thymus, 659
Respiration, organs of, 641
Respiratory nerve of Bell, external, 508, in-
ternal, 505
Restiform bodies of medulla oblongata,
452, 453
Rete mucosum of skin, 543 ; testis, 678
Retina 559, arteria centralis of, 336, 561 ;
fovea centralis of, 560 ; limbus luteus of,
560 ; membrana limitans of, 561 ; nervous
layer of, 561; nummular layer of, 561;
radiating fibres of, 561 ; sti'ucture of,
560
Retinacula of ileo-csecal valve, 610
Retrahens aurem muscle, 190
Rhomboid impression, 85 ; ligament, 157
Rhomboideus, 195, major, 221, minor, 221
Ribs, 7 1 ; angle of, 73 ; attachment of mus-
cles to, 75 ; development of 75 ; false, 72 ;
floating, 72 ; head of, 72 ; ligaments of, 147 ;
neck of, 72 ; peculiar 73 ; tuberosity of,
73 ; vertebral, 72 ; vertebro-costal, 72 ;
vertebro- sternal, 72
Rickets, 2
Ridge, internal occipital, 20 ; mylo-hyoidean,
51 ; pterygoid, 34 ; superciliary, 25 ; tem-
poral, 23, 61
Rima glottidis, 645
Ring, abdominal, external, 230, 694, internal,
697 ; femoral or crural, 705 ; fibrous of
heart, 636
744
INDEX.
Eisorius muscle, 198
Root of lung, 655
Roots of spinal nerves, 501 ; of teeth, 584 ; of
the zygomatic process, 27
Rostrum of sphenoid bone, 34 ; of corpus
callosum, 462
Rotation, 138
Rotatores spinse muscles, 227
Round ligaments of uterus, 690 ; relation
of, to femoral ring, 705 ; of liver,
615
Rugae of stomach, 605 ; of vagina, 685
Rupture of urethra, course taken by urine
in, 712
Sac, lachrymal, 567 ; of omentum, 600
Saccule of vestibule, 580
Sacculus laryngis, 646
Sacra-media artery, 375
Sacral arteries, lateral, 382 ; canal, 15; cor-
nua, 13; foramina, 12; ganglia, 540;
lymphatic glands, 435 ; nerves, 524, an-
terior branches of, 524, posterior branches
of, 524, roots of, 524 ; plexus, 525 ; vein
lateral, 419, middle, 420
Sacro-coccygeal ligaments, 154
Sacro-ihac articulation, 153
Sacro-lumbalis muscle, 225
Sacro-sciatic foramen, greater, 1 54, lesser, 1 54 ;
ligaments, 154 ; notch, greater, 79, 83,
lesser, 80, 83
Sacro-vertebral angle, 12
Sacrum, 12, articulations of, 16, attachment
of muscles to, 16, development of, 15, pe-
culiarities of, 15, structure of, 15
Sacs, dental, 589
Sagittal suture, 54
Salivary glands, 592, structure of, 594
Santorini, cartilages of, 643
Saphenous nerve, long or internal, 523, short,
528 ; opening, 278, 703 ; vein, external or
short, 418, internal or long, 417, 700
Sartorius muscle, 278
Scala tympani of cochlea, 579 ; vestibuli of
cochlea, 579
Scalae of cochlea, 579
Scalenus anticus, 217; medius, 217; pos-
ticus, 217
Scaphoid bone, hand, 103, foot, 127 ; fossa
of sphenoid, 35
Scapula, 86; articulations of, 91 ; attachment
of muscles to, 91 ; development of, 91 ;
dorsum of, 86 ; glenoid cavity of, 89 ;
head of, 89 ; ligaments of, 159 ; muscles
of, 247 ; spine of, 87 ; venter of, 86
Scapular artery, posterior, 346, supra, 345;
region, muscles of, anterior, 247, posterior,
248 ; veins, 404
Scapulo-clavicular articulation, 158
Scarfskin, 543
Scarpa's triangle, 384
Schindylesis, 135
Schneiderian membrane, 552
Schreger's analysis of bone, 2
Sclerotic, 554, structure of, 555, vessels and
nerves of, 555
Sciatic artery, 381 ; nerve, greater, 528,
lesser, 526 ; veins, 419
Scrotal hernia, 699
Scrotum, 675 ; dartos of, 675 ; lymphatics
of, 435; nerves of, 675; septum of, 675;
vessels of, 675
Sebaceous glands, 546
Sella turcica, 32, 57
Semen, 680 ; liquor seminis of, 680 ; semi-
nal granules of, 680 ; spermatoza of, 680
Semicircular canals, 577, external, 578, pos-
terior, 577, superior, 577; membranous,
580
Semilunar bone, 103, cartilages of knee, 175 ;
ganghon of fifth nerve, 485, of abdomen,
538 ; valves aortic, 635, pulmonic, 633
Semimembranosus muscle, 289
Seminal granules, 680 ; ducts, 679 ; vesicles,
679
Seminiferous tubes, 678
Semispinalis dorsi, 227, colli, 227
Semitendinosus muscle, 288
Senac, on structure of heart's valves, 633
Senses, organs of the, 542
Separation of epiphyses, 4
Septum auricularum, 630, 635 ; crurale, 706 ;
lucidum, 465 ; of medulla oblongata, 454 ;
of nose, 66, cartilage of, 551 ; pectiniforme,
673; of pons Varolii, 455; scroti, 675;
subarachnoid, 444 ; of tongue, 547 ; ven-
triculorum, 632
Serratus magnus, 246; posticus, inferior,
222, superior, 222
Sesamoid bones, 131
Shaft of a bone, its structure, 2
Sheath of arteries, 308 ; of muscles, 185 ; of
nerves, 440 ; femoral or crural, 704 ; of
rectus muscle, 235
Short bones, 2
Shoulder joint, 160 ; muscles of, 247 ; vessels
and nerves of, 160
Sigmoid artery, 373 ; cavity, greater and
lesser of ulna, 97, of radius, 101 ; flexure
of colon, 611 ; meso-colon, 602 ; notch of
lower jaw, 53
Simon, on supra-renal capsules, 664
Sinus, aortici, 635 ; cavernous, 408 ; circu-
lar, 409 ; circularis iridis, 559 ; coronary,
423, opening of in heart, 631 ; of jugular
vein, 405; of kidney, 660, 662; lateral,
408 ; longitudinal inferior, 408, superior,
407 ; maxillary, 42 ; occipital, 408 ; petrosal
inferior, 409, superior, 409; pocularis,
669 ; prostatic, 669 ; of right auricle, 630 ;
of left, 634, straight, 408 ; transverse,
409
Sinuses, 400 ; confluence of the, 408 ; eth-
moidal, 38 ; frontal, 26 ; maxillary, 42 ;
sphenoidal, 34 ; of Valsalva, aortic, 635,
pulmonary, 633
Sixth nerve, 479
Skeleton, 1. its number of pieces, 4
Skin, General Anatomy of, 542 ; appendages
of, 545 ; areolae of the, 543 ; colour of, its
origin, 544 ; corium of, 543 ; cuticle of,
543 ; derma, or true skin, 542 ; epidermis
of, 543 ; furrows of, 543, 544 ; hairs, 545 ;
muscular fibres of, 543; nails, 545 ; nerves
of, 544 ; papillary layer of, 543 ; rete
mucosum of, 543 ; sebaceous glands of,
546 ; sudoriferous, or sweat-glands of,
546 ; vessels of, 544
Skull, 19, 55 ; anterior region, 62 ; base of
INDEX.
745
Skull (continued).
external surface, 55, internal surface, 55 ;
fossa of, anterior, 55 middle, 57, posterior,
57 ; lateral region of, 61 ; tables of, 3 ;
vertex of, 55 ; vitreous table of, 3
Small intestine, cellular coat of, 607 ; mu-
cous coat of, 607 ; muscular coat of, 607 ;
serous coat of, 607 ; simple follicles, 608 ;
structui'e of, 607 ; valvul<e couniveutes,
607 ; villi of, 608
Small intestines, 606 ; duodenum, 606 ;
ileum, 607 ; jejunum, 607
Socia parotidis, 593
Soft palate, 591 ; aponeurosis of, 592 ; arches
or pillars of, 592 ; muscles of, 592 ; struc-
ture of, 591
Solar plexus, 538
Sole of foot, muscles of, first layer, 299,
second layer, 301, third layer, 302
Soleus muscle, 293
Solitary glands, 608
Space, anterior perforated, 459 ; axiUary,
348 ; intercostal, 72 ; popliteal, 389 ; pos-
terior perforated, 460
Spermatic artery, 373, 676 ; canal, 696 ; cord
arteries of, 676, course of, 676, lym-,
phatics of, 676, nerves of, 676, I'elation to
femoral ring, 705, relations of in inguinal
canal, 676, veins of, 676 ; fascia, external,
694 ; plexus of nerves, 539, of veins, 420 ;
veins, 420, 676
Spermatozoa. 680
Spheno-maxillary fissure, 62, fossa, 62
Spheno-palatine artery, 329 ; foramen, 49 ;
ganglion, 489 ; nerves, 489 ; notch, 49
Spheno-parietal suture, 54
Sphenoid bone, 32, articulations of, 36, at-
tachment of muscles to, 36, development
of, 36, greater wings of, 34, lesser wings
of, 35, pterygoid processes of, 35, spinous
process of, 34, vaginal processes of, 34
Sphenoidal fissure, 35, 57 ; process of palate,
48 ; sinuses, 34 ; spongy bones, 36
Sphincter muscle of bladder, 667 ; of rectum,
external, 710, internal, 710 ; of vagina,
714
Spinal Arteries, anterior, 344, lateral, 343,
posterior, 344, median, 344
Spinal Cord, 445, arachnoid of, 443, ar-
rangement of grey and white matter in,
446, central ligament of, 444, columns of,
446, dura mater of, 443, fissures of, 445,
foetal peculiarity of, 447, grey commissure
of, 446, grey matter of, 446, internal struc-
ture of, 446, ligamentum denticulatum of,
444, membranes of, 442, neurilemma
of, 444, pia mater of, 444, sections of,
447, substantia cinerea gelatinosa, 446,
white commissure of, 445, white matter
of, 447
Spinal nerves, 501, arrangement into
groups, 501, branches of, anterior, 502,
posterior, 502, ganglia of, 501, origin of
roots, anterior, 501, posterior, 501
Spinal veins, 415, longitudinal anterior,
416, posterior, 416
Spinal accessory nerve, 496
Spinalis cervicis muscle, 226 ; dorsi, 226
Spinal column, 5
Spines of bones, ethmoidal, 32 ; of ischium.
Spines of bones (continued).
79 ; nasal, 26, anterior, 44, posterior, 47 ;
pharyngeal, 20 ; of pubes, 80 ; of scapula,
87
Spinous process of sphenoid, 34, of tibia,
117, of vertebrae, 5
Spiral canal of cochlea, 578
Splanchnic nerve, greater, 537, lesser, 538,
smallest or renal, 538
Spleen, 23 ; capillaries of, 627 ; fibrous elas-
tic coat of, 623 ; lymphatics of, 437, 627 ;
Malpighian corpuscles of, 625 ; nerves of,
627 ; proper substance of, 624 ; relations
of, 623 ; serous coat of, 623 , size and
weight, 623 ; artery, of 625 ; structure
of, 623 ; trabeculfe of, 624 ; veins of, 627
Splenic artery, 369, distribution of, 625 ;
plexus, 539 ; vein, 422
Spongy portion of urethra, 669 ; tissue of
bon e, 2
Squamo-sphenoidal suture, 54 ; parietal su-
ture, 54
Squamous portion of temporal bone, 27
Stapedius muscle, 575
Stapes, 574 ; annular hgament of, 575
Stellate ligament, 147
Steno's duct, 593
Sternal end of clavicle, fracture of, 269 ;
foramen, 70 ; ligaments, 151 ; nerves, 504
Sterno-clavicular articulation, 156
Sterno-cleido mastoid muscle, 204
Sterno-hyoid muscle, 205
Sterno-thyroid muscle, 206
Sternum, 68, articulations of, 71, attachment
of muscles to, 71, development of, 70,
ligaments of, 151
Stomach, 602 ; alteration in position of,
603 ; alveoli of, 605 ; cellular coat of,
605 ; curvatures of, 602 ; fundus of,
602 ; gastric follicles of, 605 ; liga-
ments of, 603, lymphatics of, 436 ; mu-
cous glands of, 605, mucous mem-
brane of, 605 ; muscular coat of, 604, 605 ;
orifices of, 602 ; pyloric end of, 602 ;
pylorus, 604 ; serous coat of, 604 ; simple
follicles of, 605 ; splenic end of, 602 ;
structure of, 604 ; surfaces of, 603 ; ves-
sels and nerves of, 606
Stratiform fibro-cartilage, 134
Strise longitudinales, 462, laterales, 462
Stricture, seat of in direct inguinal hernia,
699, in femoral, 708, in obhque, 698
Stroma of ovary, 689
Stylo-glossus muscle, 210
Stylo-hyoid muscle. 208 ; nerve from facial,
481
Stylo-mastoid artery, 325 ; foramen, 30 ;
vein, 404
Stylo-maxillary ligament, 146
Stylo-pharyngeus muscle, 212
Styloid process of temporal bone, 30, of
radius, 101, of ulna, 100
Subanconeus muscle, 253
Subarachnoid space of brain, 449 ; of cord
443 ; fluid, 449 ; septum, 444
Subclavian arteries, 338, branches of, 342,
first part of, left, 339, right, 339, peculi-
arities of, 341, second portion of, 340, third,
340, surgical anatomy of, 341 ; groove, 85 ;
i.erve, 507 ; triangle, 332 ; vein, 412
74-6
INDEX.
Subclavius muscle, 245
Subcrureeus muscle, 280
Sublingual artery, 321 ; fossa, 51 ; gland,
594, vessels and nerves of, 594
Sublobular veins, 619
Submaxillary artery, 323 ; fossa, 52 ; gang-
lion, 494 ; gland, 594, nerves of, 594, ves-
sels of, 594 ; lymphatic glands, 428 ; tri-
angle, 331 ; vein, 403
Submental artery, 323 ; vein, 403
Sub-occipital nerve, 502, posterior branch
of, 506
Sub- peduncular lobe of cerebellum, 472
Subscapular aponeurosis, 247 ; artery, 352 ;
fossa, 86 ; nerves, 508
Subscapularis muscle, 248
Substantia cinerea gelatinosa, 446
Sudoriferous glands, 546
Sulci of cerebrum, 455, 456 ; transversales,
21
Supercilia, 564
Superciliary ridge, 25
Superficial palmar arcb, 361
Superficialis colli nerve, 503 ; volse artery,
359
Superior maxillary bone, 40, articulations of,
44, attachment of muscles to, 44, develoj)-
ment of, 44 ; nerve, 487
Superior meatus, 66 ; profunda artery, 365 ;
turbinated crest, 43, of palate, 47 ; vena
cava, orifice of, 631
Supinator brevis muscle, 261 ; longus, 258
Supra-clavicular nerves, 504
Supra-orbital arch, 25 ; artery, 335 ; fora-
men, 25 ; nerve, 486 ; notch, 25
Supra-renal arteries, 373 ; capsules, 663,
nerves of, 664, relations of, 664, structure
of, 664, vessels of, 664 ; plexus, 538 ; veins,
421
Supra-scapular artery, 345 ; nerve, 508
Supra-spinales muscles, 227
Supra-spinatus muscle, 248
Supra-spinous aponeurosis, 248
Supra-trochlear nerve, 481
Sural arteries, 391 ; veins, 418
Surgical Anatomy, 1 ; of abdominal aorta,
367 ; of arch of aorta, 312 ; of axilla
348 ; of axillary artery, 351
of base of bladder, 717; of brachial artery,
355
of common carotid artery, 318 ; of com-
mon iliac artery, 376
of external carotid, 319
of facial artery, 324 ; of femoral artery,
386, of femoral hernia, 700
of hamstring tendons, 289
of inguinal hernia, 692 ; of internal carotid,
334, of iliac arteries, 377 ; of ischio-rectal
region, 709
of laryngo-tracheal region, 650 ; of lingual
artery, 321
of muscles of eye, 194, of lower extremity,
303, of soft palate, 215, of u^jper ex-
tremity, 268
of CESophagus, 596
of perinseum, 709, 711 ; of popliteal arte-
ry, 390 ; of prostate gland, 716
of radial artery, 358
of subclavian artery, 341 ; of superior thv-
roid, 320
SuROiCAL Anatomy (continued).
of talipes, 297 ; of temporal artery, 326 ;
of thoracic aorta, 364 ; of triangles of
neck, 330
of ulnar artery, 361
Suspensory ligament of incus, 575 ; of lens,
563 ; of malleus, 575
Sustentaculum tali, 124
Sutura, 135; dentata, 135 ; harmonia, 135 ;
limbosa, 135 ; notha, 135 ; serrata, 135 ;
squamosa, 135 ; vera, 135
Suture basilar, 54 ; coronal, 54 ; cranial, 53 ;
ethmo-sphenoidal, 55 ; ethmoido-frontal,
55 ; frontal, 27, 55 ; fronto-malar, 65, fron-
to-sphenoidal, 55 ; intermaxillary, 58; in-
ter nasal, 63 ; lambdoid, 54 ; malo-max-
illary, 65 ; masto-occipital, 54 ; masto-
parietal, 54 ; naso-maxillary, 63 ; petro-
occipital, 54 ; petro-sphenoidal, 54 ; sagittal,
54 ; spheno-parietal, 54 ; squamo-parietal,
54 ; squamo-sphenoidal, 54 ; temporal, 30 ;
transverse, 55
Swallow's nest of cerebellum, 472
Sweat-glands, 546
Sympathetic Nerve, 532 ; cervical portion,
534 ; cranial portion, 487 ; lumbar por-
tion, 540 ; pelvic portion, 540 ; thoracic
portion, 537
Symphysis of jaw, 51 ; pubis, 80
Synarthrosis, 135
Synchondrosis sacro-iliac, 153
Synovia, 135
Synovial Membrane, 134, articular, 134,
bursal, 134, vaginal, 135 ; ankle, 139
astragalo-scaphoid, 182 ; atlo-axoid, 143
calcaueo-astragaloid, 180 ; carpal, 168
chondro - sternal, 150; costo - transverse
149; costo-vertebral, 148; elbow, 162
hip, 172 ; intercostal, 151 ; interpubic,
156; knee, 176 ; metacarpal, 168; occi-
pito-atloid, 144 ; phalanges, 170 ; radio-
ulnar, inferior, 164, superior, 163; sacro-
iliac, 153 ; scapulo-clavicular, 159; shoulder,
160 ; steruo-clavicular, 158 ; tarsal, 182 ;
tarso-metatarsal, 183 ; temporo-maxillary,
147 ; thumb, 168 ; tibio-fibular, inferior,
177, superior, 177 ; wrist, 166
Systemic arteries, 307 ; veins, 400
Tables of the skull, 3
Tsenia hippocampi, 464, 465 ; semi-circu-
laris, 463 ; violacea, 472
Tarsal bones, 122, ligaments, 180 ; cartilages
of eyelid, 564 ; hgament of eyelid, 564
Tarsea artery, 394
Tarso-metatarsal articulations, 183
Tarsus, 122 ; development of, 130
Teeth, 584 ; bicuspid, 585 ; body of, 584 ;
canine, 585 ; cement, of, 588 ; crown of
584 ; crusta petrosa of, 588 ; cortical sub-
stance of, 588 ; cuspidate, 585 ; deciduous,
584 ; dental tubuli of, 587 ; dentine of,
587 ; development of, 588 ; enamel of,
588 ; eruption of, 590 ; eye, 585 ; false
molars, 585 ; fang of, 584 ; general charac-
ters of, 584 ; growth of, 590 ; incisors,
585 ; intertubular substance of, 587 ; ivory
of, 587 ; milk, 584 ; molar, 585 ; multicus-
pidate, 585 ; permanent, 584 ; pulp cavity
INDEX.
747
Teeth continued.
of, 587 ; root of, 584 ; structure of, 587 ;
temporary, 584, 586 ; true or large molars,
585 ; wisdom, 586
Temporal artery, 325 ; anterior, 325 ; deep,
328 ; middle, 326 ; posterior, 326 ; sur-
gical anatomy of, 326 »
Temporal bone, 27 ; articulations of, 32 ;
attachment of muscles to, 32 ; develop-
ment of, 31 ; mastoid portion, 29 ; petrous
portion, 29 ; squamous portion, 27 ; struc-
ture of, 31
Temporal fascia, 199 ; fossae, 61 ; ganglion,
535 ; muscle, 200 ; nerves, deep, 491 ;
ridge, 23, 61 ; suture, 30 ; vein, 403,
middle, 403
Temporary cartilage, 3 ; teeth, 584, 586
Temporo-facial nerve, 482 ; maxillary arti-
culation, 145, vein, 403
Tendo Achillis, 293 ; palpebrarum or oculi,
191
Tendon, central, or cordiform of diaphragm,
240 ; conjoined of internal oblique and
transversalis, 695 ; structure of tendon
185
Tensor palati muscle, 214 ; tarsi muscle,
192 ; tympani muscle, 575 ; vaginae femoris
muscle, 278
Tentorium cerebelli, 448
Teres major muscle, 250 ; minor, 249
Testes, 676 ; coni vasculosi of, 678 ; cover-
ings of, 674, 677 ; tunica albuginea, 677,
vaginalis, 677, vasculosa, 677 ; gubernacu-
lum testis, 681 ; lobules of, 678 ; lympha-
tics of, 436 ; mode of descent, 680 ; rete
testis, 678 ; size and weight of, 677 ; struc-
ture of, 678 ; tubuli seminiferi of, 678 ;
vas deferens of, 679 ; vasa efferentia of,
678 ; vasa recta, 678 ; vasculum aberrans
of, 678
Theca vertebraUs, 443
Thalami optici, 467
Thigh, back of muscles of, 288 ; deep fascia,
or fascia lata, 277 ; fascia of, 276 ; muscles
of front, 276
Third nerve, 477 ; ventricle of the brain,
468
Thoracic acromial artery, 351 ; aorta, 363,
surgical anatomy of, 364 ; artery, alar,
352 ; artery, long, 352 ; duct, 426 ;
ganglia of sympathetic, 537 ; nerves, an-
terior, 508, posterior, or long, 508 ; region,
muscles of anterior, 242, lateral, 246
Thorax, General Description of, 628 ; base
of, 628 ; bones of, 68 ; boundaries of, 628 ;
cutaneous nerves of, lateral, 517 ; fasciae
of, 242 ; muscles of, 236 ; parts passing
through upper opening of, 628
Thumb, muscles of, 264
Thymus gland, 658 ; chemical composition,
659 ; lobes of, 659 ; lymphatics of, 438 ;
structure of, 659 ; vessels and nerves of,
659
Thyro-arytenoid ligament, inferior, 645 ; su-
perior, 645
Thyro-arytsenoideus muscle, 640
Thyro-epiglottic ligament, 644
Thyro-epiglottideus muscle, 647
Thyro-hyoid ligaments, 644 ; membrane,
643 ; muscle, 206 ; nerve, 484
Thyroid artery, inferior, 345, superior, 320,
surgical anatomy of, 320 ; axis, 345 ;
branches of sympathetic, 535 ; cartilage,
641 ; foramen, 81 ; ganglion, 535 ; gland,
657, chemical composition, 658, isthmus of,
658, lymphatics of, 438, situation of, 057,
structure of, 658, vessels and nerves of,
658 ; veins, inferior, 414, middle, 405, su-
perior, 405
Tibia, 116; articulations of, 120; attach-
ment of muscles to, 120 ; crest of, 118 ;
development of, 120 ; fracture of shaft of,
305; spinous process of, 117; tubercle
of, 117 ; tuberosities of, 117
Tibial artery, anterior, 392, branches of,
303, peculiarities of, 392, surgical anatomy
of, 393 ; posterior, 395, branches of, 396,
peculiarities of, 396, surgical anatomy of,
396 ; lymphatic glands, 433 ; nerve, an-
terior, 530, posterior, 529 ; recurrent ar-
tery, 393 ; veins, anterior, 418, posterior,
418
Tibialis anticus muscle, 290 ; posticus
muscle, 293
Tibio-fibular articulations, superior, 176,
middle, 177, inferior, 177 ; region, an-
terioi', muscles of, 290
Tongue, 547 ; arteries of, 550 ; fibrous sep-
tum of, 550 ; follicles of, 550 ; mucous
glands of, 550 ; mucous membrane of,
547 ; muscular fibres of, 550 ; muscles of,
209 ; nerves of, 550, papillse of, 548
Tonsillitic artery, 323
Tonsils, 592 ; nerves of, 592 ; vessels of, 692
Torcular Herophili, 21, 408
Trabeculse of corpus cavernosum, 673 ; of
spleen, 624 ; of testis, 677
Trachea, cartilages of, 650 ; glands of, 650 ;
relations of, 648 ; structure of, 650 ; sur-
gical anatomy of, 650 ; vessels and nerves
of, 650
Trachelo-mastoid muscle, 225
Tracheotomy, 651, 652
Tractus opticus, 476
Tragicus muscle, 569
Tragus, 568
Transversalis fascia, 696 ; muscle, 233, 696
Transversalis colli artery, 346 ; muscle, 225
Transverse arteries of basilar, 344 ; colon,
611 ; facial artery, 326, vein, 403 ; fissure
of brain, 465, of liver, 615 ; ligament of
hip, 172, of knee, 175, of scapula, 160 ;
meso-colon, 600, 602 ; process of a verte-
bra, 5 ; sinus, 409 ; suture, 55
Transversus auriculae, 569 ; perinsei muscle,
713, perinsei (in female), 714
Trapezium bone, 105
Trapezius muscle, 218
Trapezoid bone, 105 ; ligament, 158
Triangle, inferior carotid, 330; of Hesselbach,
699 ; of neck, anterior, 330, posterior, 331,
surgical anatomy of, 330 ; occipital, 331 ;
Scarpa's, 384 ; subclavian, 332 ; submax-
illary, 331 ; superior carotid, 330
Triangular ligament of urethra, 695, 715
Triangularis sterni muscle, 237
Triceps extensor cruris, 279; extensor cubiti,
252
Tricuspid valves, 633
Trifacial nerve, 485
748
INDEX.
Trigone of bladder, 6 67
Trochanteric fossa, 112
Trochanters, greater and lesser, 112
Trochlea of humerus, 94
Trochlear nerve, 478
True pelvis, S3 ; ligaments of bladder, 666 ;
ribs, 72 ; vertebrse, 5
Trunk, muscles of, 217
Tube, Eustachian, 673 ; Fallopian, 688
Tuber cinereum, 459 ; ischii, SO
Tubercle of the clavicle, 85 ; of the femur,
112; lachrymal, 43; laminated of cere-
bellum, 472 ; of Lower, 631 ; for odontoid
ligaments, 20 ; of scaphoid, 103 ; of the
tibia, 117; of ulna, 97; of zygoma, 28
Tubercles, genial, 51 ; of ribs, 73
Tubercula quadrigemina, 469
Tuberculo ciuereo, 454
Tuberosities of humerus, greater and lesser,
91 ; of tibia, 117
Tuberosity of ischium, 80 ; maxillary, 40 ;
of palate bone, 47 ; of radius, 101
Tubes, bronchial, 649, structure of in lung,
656
Tubuh of Ferrein, 662 ; lactiferi, 691 ; recti,
678 ; seminiferi, 678 ; uriniferi, 661
Tubulus centralis modioli, 578
Tuft, vascular, in Malpighian bodies of
kidney, 662
Tunica albuginea, 677 ; of ovary, 689 ;
Ruyschiana, 557 ; vaginalis, 675, 677 ;
vaginalis propria, 677, retiexa, 677 ; vas-
culosa testis, 677
Turbinated bone, superior, 38, inferior, 49,
middle, 38
Tutamina oculi, 564
Tympanic artery, from internal carotid, 334,
from internal maxillary, 327 ; bone, 31 ;
nerve, 481, 496, 576
Tympanum, 571 ; arteries of, 576 ; cavity
of, 571 ; membrane of, 573 ; mucous
membrane of, 575 ; muscles of, 575 ;
nerves of, 576; ossicula of, 574; veins
of, 576
Ulna, 97, articulations of, 100, development
of, lUO ; fracture of corouoid process
of, 271, of olecranon, 271, of shaft, 271 ;
muscles attached to, 100 ; sigmoid ca-
vities of, 97 ; styloid process of, 100 ;
tubercle of, 97
Ulnar artery, 360, branches of, 361, pecu-
liarities of, 361 ; relations in fore-arm,
360, in hand, 360, at wrist, 360, surgical
anatomy of, 361 ; lymphatic glands, 430 ;
nerve, 573 ; artery, recurrent, anterior,
361, posterior, 361 ; vein, anterior, 410,
posterior, 410
Umbilical arteries in foetus, 639, 640, how
obliterated, 640 ; fissure of liver, 615 ;
region, contents of, 598 ; vein, 639, 640,
how obhterated, 640
Umbilicus, 236
Unciform bone, 107
Ungual phalanges, 108
Upper extremity, arteries of, 338 ; bones
of, 84 ; ligaments of, 156 ; lymphatics of,
430 ; muscles of, 241 ; nerves of, 509 ;
veins of, 410
Urachus, 666
Ureters, nerves of, 663 ; relations of, 663 ;
structure of, 622, 663 ; vessels of, 663
Ukethra, male, 668 ; bulbous portion of,
669 ; caput gallinaginis, 668 ; membranous
portion, 669 ; prostatic portion, 668, sinus
of, 669 ; rupture of, course taken by urine,
712 ; sinus pocularis of, 669 ;' spongy
portion of, 669 ; structure of, 669 ; veru-
montanum, 668 ; female, relations of, 684,
structure of, 684
Urinary organs, 660
Uterine arteries, 378 ; nerves, 541 ; plexus
of veins, 419
Uterus, appendages of, 688 ; arbor vitse of,
6S7 ; broad ligaments of, 686 ; cavity of,
6S6 ; in foetus, 688 ; fundus, body, and
cervix of. 686 ; ligaments of, 686 ; lym-
phatics of, 435 ; during menstruation,
688 ; in old age 688, after parturition, 688 ;
during pregnancy, 688 ; at puberty, 688 ;
round ligaments of, 690 ; shape, position,
dimensions, 686 ; structure of, 687 ; ves-
sels and nerves of, 687
Uterus masculinus, 669
Utricle of vestibule, 580
Uvea, 559
Uvula, 591 ; of cerebellum, 471 ; vesicae,
668
Vagina, columns of, 685 ; lymphatics of,
436 ; orifice of, 683 ; relations of, 685 ;
situation, direction, shape, dimensions,
685 ; structure of, 685
Vaginal arteries, 378 ; plexus of nerves, 541 ;
plexus of veins, 419 ; portal plexus,
619 ; process of temporal, 30 ; processes
of sphenoid, 34 ; synovial membranes,
134
Vagus nerve, 497, ganglion of root of, 498, of
trunk of, 498
Valve of Eauhin, 610 ; coronary, 632 ; of
cystic duct, 620 ; Eustachian, 631 ; of
gall-bladder, 620 ; iho-ccecal, 610 ; of
Kerkring, 607 ; mitral, 635 ; of Vieussens,
469
Valves in right auricle, 631 ; semilunar
aortic, 635 ; pulmonic, 633 ; tricuspid,
633
Valvulfe conniventes, 607
Vas deferens, 679, structure of, 679 ; aberrans,
678
Vasa aberrantia of brachial artery, 354 ;
afferentia of tymphatic glands, 426 ; brevia
arteries, 370, veins, 422 ; efferentia of
testis, 678, of lymphatic glands, 426;
vasorum of arteries, 308, of veins, 401,
intestini tenuis arteries, 370, recta, 678
Vascular system, changes in, at birth, 640,
peculiarities in foetus, 637
Vasculum aberrans, 678
Vastus externus muscle, 279 ; intei'nus and
cruraeus, 280
Veins, General Anatomy of, 400 ; anas-
tomoses of, 400 ; coats of, 401 ; mus-
cular tissue of, 401 ; plexuses ol, 400 ;
size, form, etc., 400 ; structure of, 401 ;
valves of, 401 ; vessels and nerves of
401
INDEX.
749
Veixs or Vein'. Descriptive Anatomy of, 402
of alse nasi, 403 ; angular, 403 ; articular
of knee, 418 ; auricular anterior, 403,
posterior, 404 ; axillary, 412 ; azygos,
left lower, 415, left upper, 415, rigiit,
414
basilic, 411 : basi-vertebral, 416 ; of bone,
3 ; brachial, 411 ; brachio-cephalic or
innominate, 412 ; bronchial, 415 ; buccal,
403
cardiac, 423, anterior, 423, great, 423,
posterior, 423 ; cava superior, 414,
inferior, 420 ; cephalic, 411 ; cere-
bellar, 407 ; cerebral, 406 ; choroid
of brain, 407 ; circumflex, iliac, 419,
superficial, 417; comites brachial, 411,
interosseous, 411, radial, 411, ulnar,
411; condyloid posterior, 408; of
coipora cavernosa, 674; of corpus
spongiosum, 674 ; of corporis striati,
407 ; cystic, 423
deep, or venae comites, 400: dental in-
inferior, 403 ; diaphragmatic or phrenic,
421 ; ofdiploe, 405; dorsal spinal, 4 15, of
penis, 419 ; dorsalis nasi, 403, pedis,
418
epigastric, 419, superficial, 417; of eye-
ball, 564
facial, 402; femoral, 418; frontal, 403
of Galen, 407 ; gastric, 422 : gastro-epi-
ploic left, 422 ; gluteal, 419
haemorrhoidal inferior, 419, middle, 419,
superior, 419 ; of head, 402 : hepatic,
421
iliac, common, 419, external, 419, internal,
419 ; ilio-lumbar, 419 ; inferior cava,
420; innominate, 412; intercostal su-
perior, 414 ; interlobular, 619 ; inte-
rosseous of forearm, 411 ; intralobular,
619
jugular anterior, 404 ; external, 404 ; ex-
ternal posterior, 404 ; internal, 405
of kidney, 662
labial inferior, 403, superior, 403 ; laryn-
geal, 405; lateral sacral, 419; lingual,
405 ; of liver, 617 ; longitudinal inferior,
408 ; lumbar, 420, ascending, 420
mammary internal, 414 ; masseteric, 403 ;
mastoid, 404 ; maxillary internal, 403 ;
median cutaneous. 411, basilic, 411, ce-
phahc, 411; medulli-spinal, 416; me-
ningeal 403 ; meningo-rachidian, 416 ;
mesenteric inferior, 421, superior, 421
nasal, 403 ; of neck, 402
oblique, 423 ; obturator, 419 ; occipital,
404 ; ophthalmic, 409 ; ovarian, 421
palatine inferior, 403 ; palmar deep, 411 ;
palpebral inferior, 403, superior, 403 ;
pancreatic, 422 ; pancreatico-duodenal,
422; parotid, 403 ; peroneal, 418 ; pha-
ryngeal, 405 ; jihrenic, 421 ; plantar
external, 418, internal, 418 ; popliteal,
418 ; portal, 400, 423; profunda femoris,
418 ; pterygoid plexus, 403 ; pudic ex-
ternal, 417, internal, 419; pulmonary,
400, 424
radial, 411 ; ranine, 403 ; renal, 421
sacral, middle, 420 ; salvatella, 410 ; sa-
phenous external, or short, 418, in-
ternal or long, 417 ; sciatic, 419 ; sper-
Vein3 or Vein {continued).
matic, 420 ; spinal, 415 ; splenic, 422 ;
stylomastoid, 404; subclavian, 412; sub-
lobular, 619 ; submaxillary, 403 ; sub-
mental, 403 ; superficial, 400 ; supra-
orbital, 403 ; supra-renal, 421 ; supra-
scapular, 404 ; sural, 418 ; systemic,
400
temporal, 403, middle, 403 ; temporo-
maxillary, 403 ; thyroid inferior, 414,
middle, 405, superior, 405 ; tibial an-
terior, 418, posterior, 418 ; transverse
cervical, 404, facial, 403
ulnar anterior, 410, posterior, 410 ; um-
bihcal, 639, 640
vaginal of liver, 619 ; vasa brevia, 422 ;
ventricular, 407 ; vertebral, 412
Veins, plexuses of, ovarian, 421, 690 ; pam-
piniform, 420, 676 ; pterygoid, 403 ; sper-
matic, 420, 676 ; uterine, 419, 687 ; vaginal,
419 ; vesico-prostatic, 419
Velum pendulum palati, 591 ; interpositum,
466, arteries and veins of 467
Vena cava, superior, 414, inferior, 420
Venee comites, 400 ; Thebesii, 423 ; minimse
cordis, 423 ; vorticosee, 557
Venter of ilium, 78 ; of scapula, 86
Ventricular veins, 407
Ventricles of brain, third, 468, grey matter
of, 468 ; fourth, 472, lining membrane of,
473; fifth, 465; lateral, 463; of corpus
callosum, 461 ; of heart, left, 635, right,
openings in, 632 : of larynx, 646
Vermiform process, of cerebellum, superior,
470, inferior, 471
Vertebra dentata, 7 ; prominens, 8
Vertebrae, cervical, 5 ; development of, 11 ;
dorsal, 8 ; false, 5, 12 ; general characters,
5 ; ligaments of, 138 ; lumbar, 10 ; pedi-
cles of, 5 ; sacral, 12 ; structure of, 10 ;
true, 5
Vertebral aponeurosis, 222 ; artery, 343 ;
column, 17 ; ossification of, 12 ; foramen,
5 ; ligaments, 138 ; region, muscles of,
anterior, 215, lateral, 217; ribs, 72 ; vein,
412
Vertebro-costal ribs, 72
Vertebro-stemal ribs, 72
Vertex of skull, 55
Verumontanum, 668
Vesical artery, inferior, 378, middle, 378,
superior, 378 ; plexus of nerves, 540
Vesico-prostatic plexus of veins, 419
Vesico-uterine ligaments, 686
Vesicles Graafian, 689
Vesicula prostatica, 669
Vesiculse seminales, form and size, 679, re-
lations of, 680, structure of, 680, vessels
and nerves of, 680
Vestibular artery, 581 ; nerve, 581
Vestibule, of ear, 576 ; aqueduct of, 30 ;
of vulva, 683
Vidian artery, 329 ; canal, 35 ; nerve, 491
Vieussens, valve of, 569
ViUi, 608
Viscera abdominal, position of in regions,
598 ; pelvic, position of at outlet of pelvis,
716
Vitreous humour of the eye, 562 ; table of
the skull, 3
750
INDEX.
Vocal cords, inferior or true, 645, superior
or false, 645
Voice, organs of, 641
Voluntary muscles, 185
Vomer, 50 ; alse of, 50 ; articiilations of, 50 ;
development of, 50
Vortex of heart, 637
Vulva, 682
Wharton's duct, 504
White substance of brain, chemical analysis
of, 439
Winslow, foramen of, 600
Wisdom tooth, 586
Womb. See Uterus.
Wormian bones, 39
Wrisberg, cartilages of, 643 ; nerve of, 510
Wrist joint, 164
Xiphoid appendix, 68, 70
Y-shaped centre of acetabulum, 82
Yellow spot of retina, 561
Zygoma, 27
Zygomatic arch, 61 ; fossae, 62 ; lymphatic
glands, 428 ; process, 27
Zygomaticus major muscle, 196, minor, 196
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